Title of Invention

PLY-GBS MUTANT LYSINS

Abstract Methods, compositions and articles of manufacture useful for the treatment of various Group B streptococci (GBS) bacteria are provided. Various bacterial lysins, including certain PlyGBS mutant lysins, are provided. In particular, PlyGBS mutant lysins having lytic killing activity against Group B streptococci (GBS) bacteria are provided, including PlyGBS mutant lysins with greater killing activity against Group B streptococci (GBS) bacteria than the non- mutated PlyGBS bacteria] lysin.
Full Text PLY-GBS MUTANT LYSINS
[0001] This invention relates to the identification and use of phage associated
lytic enzymes to rapidly and specifically detect or kill certain bacteria, such as Group
B streptococci (GBS) bacteria.
BACKGROUND
[0002] Group B streptococci (GBS), or Streptococcus agalactiae, are a major
cause of neonatal bacterial infection in the United States (Baker, C. J., and M.S.
Edwards, "Group B streptococcal infections," p.1091-1156 in J. Remmington and J.
O. Klein (ed.), Infectious diseases of the fetus and newborn infants, 5th ed. The W.
B. Saunders Co. Philadelphia, PA (2001)). GBS are normally colonized in human
genital and lower gastrointestinal tracts and can be vertically transmitted from mother
to baby during a normal vaginal delivery. Common manifestations of GBS disease in
neonates include sepsis, meningitis, pneumonia and joint infections. About 21% of
pregnant women are vaginally colonized with GBS and a significant high percentage
of babies develop symptoms associated with GBS infection. For example, sepsis
occurs in 16 of 1,000 live births to women with GBS colonization, while only in 0.4 of
1,000 live births to women without GBS colonization (Regan, J. A., M. A. Klebanoff,
R. P. Nugent & 7 other authors. 1996. Colonization with group B streptococci in
pregnancy and adverse outcome. Am. J. Obstet. Gynecol. 174:1354-1360).
[0003] Intrapartum antibiotic prophylaxis (IAP) is the primary prevention
suggested by the Centers for Disease Control and Prevention (CDC) because it can
effectively reduce neonatal GBS colonization and early-onset infection (Centers for
Disease Control and Prevention, "Prevention of perinatal group B streptococcal
disease: a public health perspective," Morbid. Mortal. Weekly Rep. 45: 1-24 (1996);
and Centers for Disease Control and Prevention, "Prevention of perinatal group B
streptococcal disease: revised guidelines from CDC," Morbid. Mortal. Weekly Rep.
51: 1-22 (2002)). IAP is usually given to pregnant women colonized with GBS 4 hrs
before delivery to prevent vertical transmission. However, there are many places in
the world that GBS culture screening is not routine for pregnant women and
universal administration of antibiotics may present a potential threat to neonates.
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Antibiotic resistance is another major concern because some GBS clinical isolates
are already found to be resistant to erythromycin and clindamycin (Fernandez, M.,
M. Hickman, and C. J. Baker, "Antimicrobial susceptibilities of group B streptococci
isolated between 1992 and 1996 from patients with bacteremia or meningitis,"
Antimicrob. Agents Chemother. 42: 1517-1519 (1998); Centers for Disease Control
and Prevention, "Prevention of perinatal group B streptococcal disease: revised
guidelines from CDC", Morbid. Mortal. Weekly Rep. 51:1-22 (2002)). Thus, there is
a need for a direct and effective alternative to IAP.
[0004] One promising approach to the detection and treatment of pathogenic
bacteria is the use of bacteriophage lytic enzymes as bacteriolytic agents.
Bacteriophage lytic enzymes responsible for bacterial host lysis are also known as
lysins. Many lysins can rapidly break down the bacterial cell wall in order to release
progeny phage (Young, R. 1992. Bacteriophage lysis: mechanism and regulation.
Microbiol. Rev. 56:430-481). Structurally, lysins are commonly found as modular
proteins with an amino terminal domain that confers the enzymatic activity for a
peptidoglycan bond and a carboxy terminal domain that confers binding specificity to
a carbohydrate epitope in the bacterial cell wall (Loessner, M., K. Kramer, F. Ebel,
and S. Scherer, "C-terminal domains of Listeria monocytogenes bacteriophage
murein hydrolases determine specific recognition and high-affinity binding to
bacterial cell wall carbohydrates," (Mol. Microbiol. 44:335-349 (2002); Lopez, R., E.
Garcia, P. Garcia, and J. L. Garcia, "The pneumococcal cell wall degrading
enzymes: a modular design to create new lysins?," MicroB. Drug Resist. 3:199-211
(1997); Lopez, R., M. P. Gonzalez, E. Garcia, J. L. Garcia, and P. Garcia, "Biological
roles of two new murein hydrolases of Streptococcus pneumoniae representing
examples of module shuffling," Res. Microbiol. 151:437-443 (2002); Sheehan, M. M.,
J. L. Garcia, R. Lopez, and P. Garcia, "The lytic enzyme of the pnemococcal phage
Dp-1: a chimeric enzyme of intergeneric origin," Mol. Microbiol. 25:717-725 (1997)).
Lysins are believed to provide at least one of the following enzymatic activities
against a peptidoglycan substrate: muramidases, glucosaminidases, N-
acetylmuramyl-L-alanine amidase and endopeptidases (Young, R., "Bacteriophage
lysis: mechanism and regulation," Microbiol. Rev. 56:430-481 (1992)). Purified lysin
from a bacteriophage can be applied exogenously to affect bacterial lysis (Loeffler, J.
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M., D. Nelson, and V. A. Fischetti, "Rapid killing of Streptococcus pneumoniae with a
bacteriophage cell wall hydrolase," Science. 294:2170-2172 (2001); Loessner, M., G.
Wendlinger, and S. Scherer, "Heterogeneous endolysins in Listeria monocytogenes
bacteriophages: a new class of enzymes and evidence for conserved holin genes
within the siphoviral lysis cassettes," Mol. Microbiol. 16:1231-1241 (1995); Loessner,
M., S. K. Maier, H. Daubek-Puza, G. Wendlinger, and S. Scherer, "Three Bacillus
cereus bacteriophage endolysins are unrelated but reveal high homology to cell wall
hydrolases from different bacilli," J. Bacterid. 179:2845-2851 (1997); Nelson, D., L.
Loomis, and V. A. Fischetti, "Prevention and elimination of upper respiratory
colonization of mice by group A streptococci by using a bacteriophage lytic enzyme,"
Prot. Natl. Acad. Sci. USA. 98:4107-4112 (2001)).
[0005] Lysins are normally very specific to the bacterial species from which the
lysin derived phage was isolated (Fischetti, V. A. 2003. Novel method to control
pathogenic bacteria on human mucous membranes. Ann. N. Y. Acad. Sci. 987:207-
214; Fischetti, V. A. 2001. Phage antibacterials make a comeback. Nature
Biotechnol. 19:734-735). Although the range of bacteria targeted by lysins is less
restrictive than the corresponding bacteriophage, lysins still maintain a degree of
specificity, having minimal effects on other bacteria including commensal organisms.
While bacteriophage host ranges are largely restrictive, recognizing only one specific
antigen on its bacterial host, phage lysins are less restrictive, recognizing a specific
carbohydrate molecule common to the particular species of host bacteria.
[0006] Bacterial resistance to phage lysins is believed to be less likely to arise as
compared with bacteriophage adsorption for at least two reasons: first, bacterial lysis
upon exposure to lysin is almost immediate, not giving bacteria much possibility for
mutation and second, lysins bind to highly conserved molecules in the bacterial cell
wall that are under selective pressure not to mutate. In contrast, bacterial resistance
to many antibiotics is often easily identified. Furthermore, the problem with lysogenic
conversion is reduced or eliminated with phage lysins, and animal testing and
treatment can be performed effectively using lysins.
[0007] There is an ongoing need for therapies and agents effective in the
diagnosis and control of bacterial contamination, colonization and infection. In
addition, compounds with bacteriocidal effects may be useful in the decontamination
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of bacteria on inanimate surfaces and objects. The bactiophage lytic enzymes
provided are useful in providing agents useful in the detection or killing of Group B
streptococci (GBS) bacteria.
SUMMARY
[0008] The present invention relates to bacterial lysins comprising a PlyGBS
peptide variant having bacterial killing activity. For example, the PlyGBS peptide
variant may be a PlyGBS mutant lysine having a lytic killing activity against a Group
B streptococci bacteria that is greater than the killing activity of the PlyGBS peptide
against the same bacteria.
[0009] Lysins with improved lytic activity against GBS cells compared to the lytic
activity of PlyGBS enzyme (SEQ ID NO:1) are disclosed. Hyperactive PlyGBS
mutant lysins may provide greater killing activity against GBS cells compared with
the PlyGBS protein alone, as evidenced by both in vitro and in vivo testing. The
lysins may be mutant lytic enzymes derived from PlyGBS protein lytic mutant
enzymes using DNA mutagenesis methods applied to the plyGBS gene.
PolypeoPlyGBS mutant enzymes that display increased lytic activity against GBS
protein are also identified and characterized.
[0010] The killing activity of PlyGBS lysins, such as PlyGBS mutant lysins, can be
quantified by performing an in vitro bacterial killing assay described in Example 3
below, or by performing an in vivo bacterial killing assay described in Example 4
below. A hyperactive PlyGBS mutant may provide at least 1.5-fold to about 40-fold
greater lytic activity than PlyGBS (SEQ ID NO:1) against GBS cells., at least about
14-fold to about 40-fold greater lytic activity, or at least about 25-fold to about 40-fold
greater lytic activity. Hyperactive PlyGBS mutant lysins include those selected from
the group: PlyGBS 86-6 (SEQ ID NO:2), PlyGBS 80 (SEQ ID NO:3), PlyGBS 90-8
(SEQ ID NO:4), PlyGBS 90-1 (SEQ ID NO:5), PlyGBS 94 (SEQ ID NO:8) and
PlyGBS 95 (SEQ ID NO:9). PlyGBS (SEQ ID NO:1) contains an N-terminal [amino
acid (aa) 1-107] endopeptidase domain, a central (aa 150-394) muramidase domain
and a C-terminal region (aa 395-443). Mutant PlyGBS86-6 (SEQ ID NO:2) (SEQ ID
NO:2) has one amino acid change from aspartic acid to glutamic acid (D374E).
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Mutant PlyGBS80 (SEQ ID N0:3) (aa 1-164) (SEQ ID N0:3) and PlyGBS90-8 (SEQ
ID N0:4) (aa 1-138) (SEQ ID N0:4) are truncated mutants due to stop codons
brought by nonsense mutations. PlyGBS90-1 (SEQ ID NO:5) (SEQ ID NO:5) was
derived from an out-of-frame deletion which deleted bp 424-1255 in plyGBS gene
and as a result, it encodes first 141 amino acids of PlyGBS plus extra 13 amino
acids (DGHALTIQSRRNG) due to the frame shift of the C-terminal region (bp 1256-
1332) of plyGBS gene. Hyperactive PlyGBS mutant PlyGBS94 (SEQ ID NO:8)
(SEQ ID NO:8) contains the N-terminal endopeptidase domain (first 146 amino
acids) and is similar to mutant PlyGBS90-8 (SEQ ID NO:4) (first 138 amino acids)
(SEQ ID NO:4). A similar level of lytic activity was observed in these two mutants.
PlyGBS95 (SEQ ID NO:9) (SEQ ID NO:9) has an in-frame deletion of central
muramidase domain (deletion between aa 147-348).
[0011] The structures of certain PlyGBS mutant lysins are also disclosed.
Several hyperactive PlyGBS mutants include truncation mutants that contain only the
endopeptidase domain from the N-terminal region of PlyGBS and represent about
one-third of the wild type PlyGBS (SEQ ID NO:1) in length. These mutants may
have 25-40 fold increase in specific activities compared to PlyGBS, and also may
have a similar activity spectrum against several streptococcal species. PlyGBS has
two putative catalytic domains and a C-terminal undesignated domain. Comparison
of the PlyGBS mutants PlyGBS95 (SEQ ID NO:9) (SEQ ID NO:9) and PlyGBS94
(SEQ ID NO:8) (SEQ ID NO:8) indicates that the deletion of the C-terminus has no
significant effect on its specificity or on lytic activity. The hyperactive PlyGBS
mutants PlyGBS94 (SEQ ID NO:8) (SEQ ID NO:8), PlyGBS90-1 (SEQ ID NO:5)
(SEQ ID NO:5) and PlyGBS90-8 (SEQ ID NO:4) (SEQ ID NO:4) may have
truncations in the central and C-terminal regions, and appear to be similar to
lysozyme in that they only have a catalytic domain without a cell-wall binding
domain. The endopeptidase domain present in these mutants is nearly identical to
the CHAP domain recently identified in another lytic enzyme from GBS
bacteriophage B30, PlyGBS (SEQ ID NO:1) (Pritchard, D. G., S. Dong, J. R. Baker,
and J. A. Engler, "The bifunctional peptidoglycan lysin of Streptococcus agalactiae
bacteriophage B30," Microbiology 150: 2079-2087 (2004)). However, the CHAP
domain by itself in these truncated mutants is not only active against GBS, but is
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significantly increased in activity (from 25 to 40 fold) over the wild type PlyGBS (SEQ
ID NO:1). Although CHAP domains are widely present in many phage lysins, none
of these CHAP domains has been reported to have lytic activity without the
association of a cell-wall binding domain.
[0012] Biochemical characteristics of the hyperactive PlyGBS mutants, such as
storage stability and optimum pH, have been compared with PlyGBS (SEQ ID NO:1).
The mutant PlyGBS90-1 (SEQ ID NO:5) (SEQ ID NO:5) has its optimum activity
when salt concentration is 50-100 mM, while the optimum NaCI concentration for
wild-type PlyGBS (SEQ ID NO:1) is around 200 mM. Notably, the mutant
PlyGBS90-1 (SEQ ID NO:5) (SEQ ID NO:5) maintains lytic activity against all the
streptococcus species that are sensitive to PlyGBS (SEQ ID NO:1), even though the
PlyGBS90-1 (SEQ ID NO:5) (SEQ ID NO:5) mutant contains only one-third of the
wild-type PlyGBS (SEQ ID NO:1).
[0013] The hyperactive PlyGBS mutants are more lytically active than PlyGBS
and can kill GBS at a faster rate than wild-type PlyGBS, providing an advantage for
future intrapartum therapy that would require time-effectiveness. Hyperactive
PlyGBS mutants may be administered in vivo, resulting in reduction of GBS
colonization. For example, the hyperactive PlyGBS mutant PlyGBS90-1 (SEQ ID
NO:5) (SEQ ID NO:5) was used in mouse vaginal model to test the efficacy of
reducing GBS colonization in vivo. A single dose of PlyGBS90-1 (SEQ ID NO:5)
(SEQ ID NO:5) reduced the GBS colonization from 5.54 logs (about 3.5x105 cfu per
mouse on average) before treatment to 1.68 logs (less than 50 cfu per mouse) 4 hrs
post-treatment. Administration of hyperactive PlyGBS mutants in vivo may be used,
for instance, to reduce the neonatal GBS infection during delivery, providing an
alternative approach to replace intrapartum antibiotic prophylaxis.
[0014] Other systems, methods, features and advantages of the invention will be,
or will become, apparent to one with skill in the art upon examination of the following
figures and detailed description. It is intended that all such additional systems,
methods, features and advantages be included within this description.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention can be better understood with reference to the following
drawings and description. The componenets in the figures are not necessarily to
scale, and provide an illustration of certain aspects of the invention.
[0016] Fig. 1 is a table listing the PlyGBS sequence (SEQ ID NO:1) and
sequences for various PlyGBS mutants described (SEQ ID NOS: 2-9).
[0017] Fig. 2 is a schematic diagram of PlyGBS (SEQ ID NO:1) and several
PlyGBS mutants having increased lytic activity against GBS cells.
[0018] Fig. 3 is a commassie blue-stained SDS-PAGE gel (4-20% gradient) for
purified PlyGBS90-8 (SEQ ID NO:4) (lane 1), PlyGBS90-1 (SEQ ID NO:5) (lane 2),
and wild type PlyGBS (lane 3), with the molecular mass of the protein ladder is
presented in kilodaltons (KDa).
[0019] Fig. 4 is a schematic diagram of PlyGBS and several truncated mutants.
[0020] Fig. 5A is a graph showing the relative activity of PlyGBS, PlyGBS90-1
(SEQ ID NO:5) and PlyGBS90-8 (SEQ ID NO:4) at 4oC; Fig. 5B is a graph showing
the stability of PlyGBS, PlyGBS90-1 (SEQ ID NO:5) and PlyGBS90-8 (SEQ ID NO:4)
at 4oC Store in 25% glycerol at -80oC.
[0021] Fig. 6A is a graph comparing the killing effect for PlyGBS and PlyGBS90-1
(SEQ ID NO:5) at different amounts (2, 10, 50, and 100 ug) of PlyGBS and
PlyGBS90-1 (SEQ ID NO:5); Fig. 6B is a graph comparing the killing effect for
PlyGBS and PK/GBS90-1 (SEQ ID NO:5) using the same amount of PlyGBS and
PlyGBS90-1 (SEQ ID NO:5) (about3,000 ug) in the in vitro viability.
[0022] Fig. 7 is a graph showing the effect of salt concentration on enzymes' lytic
activity.
[0023] Fig. 8 is a graph showing lysin specificity of PlyGBS (SEQ ID NO:1) and
PlyGBS90-1 (SEQ ID NO:5) in an in vitro assay.
[0024] Fig. 9 is a graph showing the control of GBS colonization in mice vagina
with PlyGBS (SEQ ID NO:1) or PlyGBS90-1 (SEQ ID NO:5).
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DETAILED DESCRIPTION
[0025] Definitions of certain terms used and their applicability to the disclosure
are provided below.
[0026] The term "hyperactive PlyGBS mutants" refers to PlyGBS mutant lysins
with enhanced activity against GBS compared to PlyGBS enzyme under
substantially identical testing conditions.
[0027] The term "isolated" means at least partially purified from a starting
material.
[0028] The term "purified" means that the biological material has been
measurably increased in concentration by any purification process, including by not
limited to, column chromatography, HPLC, precipitation, electrophoresis, etc.,
thereby partially, substantially or completely removing impurities such as precursors
or other chemicals involved in preparing the material. Hence, material that is
homogenous or substantially homogenous (e.g., yields a single protein signal in a
separation procedure such as electrophoresis or chromatography) is included within
the meanings of isolated and purified. Skilled artisans will appreciated that the
amount of purification necessary will depend upon the use of the material. For
example, compositions intended for administration to humans ordinarily must be
highly purified in accordance with regulatory standards.
[0029] The term "lytic enzyme genetically coded for by a bacteriophage" refers to
a polypeptide having at least some lytic activity against the host bacteria.
[0030] "Polypeptide" refers to a molecule comprised of amino acids which
correspond to polypeptides encoded by a polynucleotide sequence which is naturally
occurring. The polypeptide may include conservative substitutions where the
naturally occurring amino acid is replaced by one having similar properties, where
such conservative substitutions do not alter the function of the polypeptide (see, for
example, Lewin "Genes V" Oxford University Press Chapter 1, pp. 9-13 1994).
[0031] "A native sequence phage associated lytic enzyme" refers to a polypeptide
having the same amino acid sequence as an enzyme derived from nature. Such
native sequence enzyme can be isolated from nature or can be produced by
recombinant or synthetic means. The term "native sequence enzyme" specifically
encompasses naturally occurring forms (e.g., alternatively spliced or modified forms)
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and naturally-occurring variants of the enzyme. In one example, the native
sequence enzyme is a mature or full-length polypeptide that is genetically coded for
by a gene from a bacteriophage specific for Group B streptococci (GBS).
[0032] The term "about" used with reference to a quantity includes variations in
the recited quantity that are equivalent to the quantity recited, for instance an amount
that is insubstantially different from a recited quantity for an intended purpose or
function.
[0033] The term "effective amount" refers to an amount of an active ingredient
sufficient to achieve a desired effect without causing an undesirable side effect. In
some cases, it may be necessary to achieve a balance between obtaining a desired
effect and limiting the severity of an undesired effect. The amount of active
ingredient used will vary depending upon the type of active ingredient and the
intended use of the composition of the present invention.
[0034] A "variant polypeptide sequence phage associated lytic enzyme" means a
functionally active lytic enzyme genetically coded for by a bacteriophage specific for
Group B streptococci (GBS), or Streptococcus agalactiae, having at least 50%, 55%,
60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99%, or even at least
99.5% amino acid sequence identity with a sequence described.
[0035] "Percent (%) polypeptide sequence identity" with respect to the lytic
enzyme polypeptide sequences identified here is defined as the percentage of amino
acid residues in a candidate sequence that are identical with the amino acid residues
in the specific lytic enzyme polypeptide sequence, after aligning the sequences and
introducing gaps, if necessary, to achieve the maximum percent sequence identity,
and not considering any conservative substitutions as part of the sequence identity.
Methods for alignment for purposes of determining percent amino acid sequence
identity are described below.
PlyGBS Lysins
[0036] Bacteriophage lysins with killing activity against Group B streptococci
(GBS) bacteria are provided. Preferred bacteriophage lysins are hyperactive
PlyGBS mutant enzymes of PlyGBS lysin with enhanced killing activity against GBS
compared to PlyGBS activity and its variants. Several hyperactive PlyGBS mutant
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enzymes with killing activity against GBS are identified and characterized in the
examples described below. Other examples provide lysins with specific activity
against other gram positive bacteria, which include variants and fragments of the
lysins described.
[0037] The phage muralytic enzyme, PlyGBS, maybe used to lyse GBS cells in
vitro and in vivo, for example as described in Cheng, Q. et al., "Removal of group B
streptococci colonizing the vagina and oropharynx of mice with a bacteriophage lytic
enzyme," Antimicrob. Agents Chemother. 49: 111-117 (2005). PlyGBS belongs to a
group of bacteriophage lysins that can kill bacteria by digesting the bacteria cell wall,
making cells susceptible to osmotic lysis. For example, in a mouse model, a single
dose of PlyGBS can significantly reduce GBS colonization in both the vagina and
oropharynx. Administration of a phage muralytic enzyme such as PlyGBS is a
promising alternative to intrapartum antibiotic prophylaxis in order to reduce vaginal
GBS colonization in pregnant women before delivery, or to decontaminate newborns
at various body sites, thus reducing the incidence of GBS-associated neonatal
infections.
[0038] Lysins generally occur in a modular structure. The N-terminal module
consists of a catalytic domain believed to possess the ability to break down the
bacterial cell wall of certain bacteria. Ezymatic activities often associated with the
catalytic domain are amidases, endopeptidases, glucosamidases and muramidases.
The C-terminal module consists of a binding domain that is believed to have an
affinity for a carbohydrate epitope on the target bacteria cell wall. The binding
domain is believed to determine the specificity of the lysin.
[0039] Bacteriophage lytic agents effective against GBS bacteria are provided,
along with corresponding polypeptide and polynucleotide sequences relating to the
same. Compositions comprising the lytic enzymes provided may be useful in the
diagnosis, treatment, and decontamination applications relating to several types of
gram positive bacteria, as described, including GBS bacteria. Methods of treatment
and decontamination using compositions comprising the lytic enzymes, polypeptides
or polynucleotide sequences also are disclosed.
[0040] Hyperactive PlyGBS mutant enzymes exhibiting a lytic effect on BGS
bacterial strains, and particularly, the lysins have killing activity against one or more
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GBS bacterial species are described. The lysins include hyperactive PlyGBS mutant
lysins comprise a polypeptide sequence having at least 70%, 75%, 80%, 85%, 90%,
95%, 96%, 97%, 98%, 99% or greater homology to SEQ ID NO:2, SEQ ID NO:3,
SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:8, or SEQ ID NO:9.
[0041] The following references relating to the therapeutic application of lytic
enzymes as an antibacterial agent are incorporated herein by reference in their
entirety: Cheng, Q., D. Nelson, S. W. Zhu, and V. A. Fischetti, "Removal of group B
streptococci colonizing the vagina and oropharynx of mice with a bacteriophage lytic
enzyme," Antimicrob. Agents Chemother. 49: 111-117 (2005); Loeffler, J. M., D.
Nelson, and V. A. Fischetti. 2001. Rapid killing of Streptococcus pneumoniae with a
bacteriophage cell wall hydrolase. Science 294: 2170-2172; Nelson, D., L. Loomis,
and V. A. Fischetti. 2001. Prevention and elimination of upper respiratory
colonization of mice by group A streptococci by using a bacteriophage lytic enzyme.
Proc. Natl. Acad. Sci. USA 98: 4107-4112; and Schuch, R., D. Nelson, and V. A.
Fischetti. 2002. A bacteriolytic agent that detects and kills Bacillus anthracis. Nature
418:884-889.
[0042] The killing activity of PlyGBS lysins, such as PlyGBS mutant lysins, can be
quantified by performing an in vitro bacterial killing assay described in Example 3
below, or by performing an in vivo bacterial killing assay described in Example 4
below.
Mutagenic PlyGBS Mutants
[0043] Referring to the table in Fig. 1, hyperactive PlyGBS mutant lysins include
lysins selected from the group consisting of PlyGBS 86-6 (SEQ ID NO:2), PlyGBS 80
(SEQ ID NO:3), PlyGBS 90-8 (SEQ ID NO:4), PlyGBS 90-1 (SEQ ID NO:5), PlyGBS
94 (SEQ ID NO:8) and PlyGBS 95 (SEQ ID NO:9). Fig. 2 is a schematic diagram of
PlyGBS and several mutants produced by random mutagenesis. PlyGBS (SEQ ID
NO:1) contains an N-terminal [amino acid (aa) 1-107] endopeptidase domain, a
central (aa 150-394) muramidase domain and a C-terminal region (aa 395-443).
Mutant PlyGBS86-6 (SEQ ID NO:2) has one amino acid change from aspartic acid to
glutamic acid (D374E). Mutant PlyGBS80 (SEQ ID NO:3) (aa 1-164) and
PlyGBS90-8 (SEQ iD NO:4) (aa 1-138) are truncated mutants due to stop codons
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brought by nonsense mutations. PlyGBS90-1 (SEQ ID NO:5) came from an out-of-
frame deletion which deleted bp 424-1255 in plyGBS gene and as a result, it
encodes first 141 amino acids of PlyGBS plus extra 13 amino acids
(DGHALTIQSRRNG) due to the frame shift of the C-terminal region (bp 1256-1332)
of plyGBS gene.
[0044] Two hyperactive PlyGBS mutant lysins were obtained from mutator strain
E. coli XL-1 Red. The first, PlyGBS86-6 (SEQ ID NO:2), has a single point mutation
resulting in the amino acid change from aspartic acid to glutamic acid (D374E). The
PlyGBS86-6 (SEQ ID NO:2) mutant has a specific activity 14 fold higher than wild
type PlyGBS (SEQ ID NO:1). The second mutant, PlyGBS80 (SEQ ID NO:3), has a
stop codon in the center of plyGBS gene (Q164Stop) resulting in a truncated
molecule. The PlyGBS80 (SEQ ID NO:3) mutant contains only the first 163 amino
acids of wild type PlyGBS (SEQ ID NO:1), but has a specific activity 1.5-fold higher
than PlyGBS (SEQ ID NO:1).
[0045] Two hyperactive mutants were identified from PCR random mutagenesis.
The mutant PlyGBS90-8 (SEQ ID NO:4) is similar to PlyGBS80 (SEQ ID NO:3) in
that both are truncated mutants as a result of the incorporation of a stop codon. The
PlyGBS90-8 (SEQ ID NO:4) mutant has the first 138 amino acids of PlyGBS (SEQ
ID NO:1). Significantly, the PlyGBS90-8 (SEQ ID NO:4) mutant has a specific
activity that is about 25-fold higher than the wild-type PlyGBS. Another mutant,
PlyGBS90-1 (SEQ ID NO:5), does not include the region bp 424-1255 in the plyGBS
gene. As a result, it encodes only the first 141 amino acids of PlyGBS (SEQ ID
NO:1) plus an extra 13 amino acids due to the frame shift of the C-terminal region
(bp 1256-1332) of plyGBS gene. This mutant has a specific activity that is about 40-
fold higher than wild type.
[0046] The two hyperactive mutants, PlyGBS90-1 (SEQ ID NO:5) and PlyGBS90-
8 (SEQ ID NO:4), were purified using Q-Sepharose anion exchange chromatography
and the active fractions were pooled and analyzed on a gradient SDS-PAGE gel. As
shown in Fig. 3, the PlyGBS90-1 (SEQ ID NO:5) and PlyGBS90-8 (SEQ ID NO:4)
mutants migrated close to regions for calculated molecular weight (17.0, 15.3 KDa)
listed in Table 1. Fig. 3 shows a commassie blue-stained SDS-PAGE gel (4-20%
gradient) for purified PlyGBS90-8 (SEQ ID NO:4) (lane 1), PlyGBS90-1 (SEQ ID
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N0:5) (lane 2), and wild type PlyGBS (lane 3), with the molecular mass of the protein
ladder presented in kilodaltons (KDa).
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Table 1 Characteristics ofwtPlyGBS and two hyperactive PlyGBS mutant lysins

Protein Total Amino acids Calculated Molecular
Weight (KDa) Isoelectric Point
(Pi)
PLYGBS (SEQ
IDN0:1) 443 49.6 4.88
4.99
PLYGBS90-1
(SEQ ID N0:5) 154 17.0 4.50
PLYGBS90-8
(SEQ ID N0:4) 138 15.3
PlyGBS Deletion Mutants
[0047] PlyGBS (SEQ ID NO:1) has two catalytic domains, an endopeptidase and
a muramidase, and a C-terminal undesignated domain. (Cheng, Q., D. Nelson, S.
W. Zhu, and V. A. Fischetti, "Removal of group B streptococci colonizing the vagina
and oropharynx of mice with a bacteriophage lytic enzyme," Antimicrob. Agents
Chemother. 49: 111-117 (2005)). Several of the PlyGBS mutants identified as
hyperactive PlyGBS mutants are truncated mutants containing only one catalytic
domain but still having higher activity than wild- type PlyGBS. Deletion mutants were
designed based on the domain organization of PlyGBS. The deletion of C-terminus
provides PlyGBS mutants that retain the specificity and lytic activity of the PlyGBS
(SEQ ID NO:1) lytic enzyme. The deletion of C-terminus had no subtantial effect on
its specificity or on lytic activity as illustrated by comparing the hyperactive deletion
mutants PlyGBS95 (SEQ ID NO:9) and PlyGBS94 (SEQ ID NO:8). The hyperactive
mutants (PlyGBS94 (SEQ ID NO:8), PlyGBS90-1 (SEQ ID NO:5), and PlyGBS90-8
(SEQ ID NO:4)) have truncations in the central and C-terminal regions, and appear
to be similar to lysozyme in that they only have a catalytic domain without a cell-wall
binding domain. However, no significant lytic activity was observed for egg white
lysozyme (Sigma, St. Louis, MO) against GBS as well as many other bacterial
species targeted by these truncated PlyGBS mutants. The endopeptidase domain
present in these mutants is similar to the CHAP domain recently identified in the
-14-

PlyGBS lytic enzyme (SEQ ID N0:1) from GBS bacteriophage B30. Pritchard et a/.,
"The bifunctional peptidoglycan lysin of Streptococcus agalactiae bacteriophage
B30," Microbiology. 150: 2079-2087 (2004). However, the CHAP domain by itself in
the hyperactive PlyGBS truncated mutants is not only active against GBS, but is
significantly increased in activity (from about 1.5 to about 40 fold) over the wild type
PlyGBS (SEQ ID NO:1). Although CHAP domains are widely present in many phage
lysins, CHAP domains do not typically have lytic activity without the association of a
cell-wall binding domain.
[0048] Fig. 4 is a schematic diagram of PlyGBS and several truncated mutants.
Mutant PlyGBS92 (SEQ ID NO:6) only contains central muramidase domain (aa
150-394), while PlyGBS93 (SEQ ID NO:7) has muramidase plus C-terminal domains
(aa 150-443). Mutant PlyGBS94 (SEQ ID NO:8) contains the N-terminal
endopeptidase domain (aa 1-146). For comparison, PlyGBS95 (SEQ ID NO:9) was
constructed which has an in-frame deletion of central muramidase domain (deletion
between aa 147-348). As shown in Fig. 4, hyperactive PlyGBS mutant PlyGBS94
(SEQ ID NO:8) contains the N-terminal endopeptidase domain (first 146 amino
acids) and is similar to mutant PlyGBS90-8 (SEQ ID NO:4) (first 138 amino acids)
obtained above. A similar level of lytic activity was observed in these two mutants.
Mutant PlyGBS92 (SEQ ID NO:6) contains the putative muramidase domain located
in the center of PlyGBS, while the PlyGBS93 (SEQ ID NO:7) mutant contains the
muramidase domain plus the C-terminal region. Compared with the active
endopeptidase domain present in mutant PlyGBS94 (SEQ ID NO:8), neither of these
deletion mutants had any lytic activity against GBS. The lytic activity of a mutant
(PlyGBS95 (SEQ ID NO:9)) containing an in-frame deletion of the central
muramidase domain (Fig. 4) also was analyzed. The mutant has a lytic activity
similar to mutant PlyGBS94 (SEQ ID NO:8).
Protein Stability of PlyGBS Hyperactive Mutants
[0049] Fig. 5A is a graph showing the relative activity of PlyGBS, PlyGBS90-1
(SEQ ID NO:5) and PlyGBS90-8 (SEQ ID NO:4) at 4°C. Fig. 5B is a graph showing
the stability of PlyGBS (SEQ ID NO:1), PlyGBS90-1 (SEQ ID NO:5) and PlyGBS90-8
(SEQ ID NO:4) in 25% glycerol at 80°C. To obtain the data for the graphs in Fig. 5A
-15-,

and Fig. 5B, PlyGBS (SEQ ID N0:1) and hyperactive mutants PlyGBS90-1 (SEQ ID
N0:5) and PlyGBS90-8 (SEQ ID N0:4) were stored in aliquots at 4°C (Fig. 5A) in
buffer and -80°C (Fig. 5B) in 25% glycerol. At different time points, the lytic activity
of these samples was measured by in vitro lytic activity against GBS and the Vmax
values were determined to calculate relative activity. As shown in Fig. 5A, at 4°C,
wild type PlyGBS is stable for more than 40 days, while only 25% and 31.2% activity
was retained for the same period for mutant PlyGBS90-1 (SEQ ID NO:5) and
PlyGBS90-8 (SEQ ID NO:4), respectively, and nearly lost at 60 days. However,
when we stored these proteins in 25% glycerol at -80°C (Fig. 5B), all 3 proteins had
a better stability profile up to 40 days with less of a loss at 60 days.
Comparison of Lytic Activity of PlyGBS with Hyperactive PlyGBS Mutant
Lysins
[0050] Fig. 6A and Fig. 6B are graphs showing a comparison of killing effect for
PlyGBS and PlyGBS90-1 (SEQ ID NO:5) using different amounts of PlyGBS (SEQ
ID NO:1) and mutant PlyGBS90-1 (SEQ ID NO:5) (2, 10, 50, and 100 ug) in an in
vitro assay to measure the lytic activity by the determination of Vmax. To obtain the
assay results illustrated in Fig. 6A, different amounts (2, 10, 50, and 100 ug) of
PlyGBS (SEQ ID NO:1) and PlyGBS90-1 (SEQ ID NO:5) were used in the in vitro
assay and the decrease of OD600 was monitored by a spectrophotometer. The lytic
activity was expressed as the initial velocity of the decrease in absorbance over time
(-mOD600/min). As shown in Fig. 6A, the Vmax is only -22.8 mOD6oo / rnin when
100 ug of wild type PlyGBS (SEQ ID NO:1) was used, while the Vmax values are -
60.5 and -266.5 mOD6oo / min for 10 ug and 100 ug of mutant PlyGBS90-1 (SEQ ID
NO:5), respectively. Vmax measures the initial velocity of ODeoo drop, the rate of cell
lysis, and is likely to be underestimated when 100 ug of hyperactive mutant
PlyGBS90-1 (SEQ ID NO:5) is used because cell lysis occurred too rapidly to be
measured accurately under this condition.
[0051] The efficacy of mutant PlyGBS90-1 (SEQ ID NO:5) in an in vitro cell
viability assay was tested. To obtain the assay results illustrated in Fig. 6B, the
same amount of PlyGBS (SEQ ID NO:1) and PlyGBS90-1 (SEQ ID NO:5) (about
3,000 ug) was used in the /// vitro viability assay. As shown in Fig. 6B, cell viability
-16-

decreased about 6 logs after 60 min incubation with mutant PlyGBS90-1 (SEQ ID
NO:5), and only 2-logs for wild type PlyGBS over the same period. At 10 min
incubation, the cell viability decreased 3 logs for the mutant and less than 1 log for
the wild-type. These results indicate that the mutant enzyme has a significantly
increased lytic activity against GBS.
[0052] Lysin activity of the PlyGBS lysins can be affected by the salt
concentration. To obtain the results illustrated in the graph of Fig. 7, the lytic activity
of PlyGBS (SEQ ID NO:1) and mutant PlyGBS90-1 (SEQ ID NO:5) were measured
at various NaCI salt concentrations raging from 0 to 500 mM. Fig. 7 is a graph
showing the effect of salt concentration on the lytic activity of PlyGBS (SEQ ID NO:1)
and PLYGBS90-1 (SEQ ID NO:5) mutant. To obtain the data illustrated in Fig. 7,
purified PlyGBS (SEQ ID NO:1) and PlyGBS90-1 (SEQ ID NO:5) were dialyzed
against 2 mM Tris-HCI (pH7.4) overnight and various amounts of 5M NaCI were
added to provide the desired salt concentration for the in vitro activity assay. The
highest lytic activity under optimum salt concentration for PlyGBS (SEQ ID NO:1) or
PlyGBS90-1 (SEQ ID NO:5) is considered as 100% for the standard to calculate
relative activity. As shown in Fig. 7, the optimum NaCI concentration for wild type
PlyGBS (SEQ ID NO:1) is about 200 mM, while the optimum for mutant PlyGBS90-1
(SEQ ID NO:5) shifted to about 50-100 mM. The results illustrated in Fig. 7 suggest
that although the wild-type PlyGBS (SEQ ID NO:1) enzyme retained activity over a
wider range of salt than the PlyGBS90-1 (SEQ ID NO:5) mutant, the mutant was
more sensitive to these changes. When the pH activity profile of mutant PlyGBS90-1
(SEQ ID NO:5) was compared with wild-type PlyGBS (SEQ ID NO:1), both had a
peak at pH 5.0.
[0053] The activity spectrum of mutant PlyGBS90-1 (SEQ ID NO:5) lysine was
compared with wild-type PlyGBS (SEQ ID NO:1) lysine using the same amount of
lysin. PlyGBS (SEQ ID NO:1) has a relatively broad spectrum against a number of
streptococcal groups and species, such as S. pyogenes (GAS), S. equi (GCS) and
S. salivarius (Cheng, Q., D. Nelson, S. W. Zhu, and V. A. Fischetti, "Removal of
group B streptococci colonizing the vagina and oropharynx of mice with a
bacteriophage lytic enzyme," Antimicrob. Agents Chemother. 49: 111-117 (2005),
incorporated by reference herein in its entirety). Fig. 8 is a graph comparing the lysin
-17-

specificity of PlyGBS (SEQ ID NO:1) and PlyGBS90-1 (SEQ ID NO:5). To obtain the
data illustrated in Fig. 8, the same dose of PlyGBS or PlyGBS90-1 (SEQ ID NO:5)
(40 U) was used in the in vitro assay and lytic activity was expressed as -
mOD600/min. Surprisingly, both enzymes had a similar level of lytic activity (Vmax)
against GBS and S. salivarius (Fig. 8) as well as some other streptococcal species.
Other bacterial species were tested in which the wild type PlyGBS (SEQ ID NO:1)
enzyme had little to no activity (i.e., Staphylococcus aureus, and Bacillus cereus),
and the PlyGBS90-8 (SEQ ID NO:4) mutant enzyme demonstrated a similar pattern
of specificity, except a small activity was found with B. cereus (Fig. 8). A similar
result was observed with some of our other truncated mutants, such as PlyGBS80
(SEQ ID NO:3) and PlyGBS90-8 (SEQ ID NO:4), which show some killing effect
against B. cereus.
[0054] The purified mutant PlyGBS90-1 (SEQ ID NO:5) preparation was tested
for its lytic activity against GBS in a mouse vaginal model as described in the
Examples below, and in Cheng, Q., D. Nelson, S. W. Zhu, and V. A. Fischetti,
"Removal of group B streptococci colonizing the vagina and oropharynx of mice with
a bacteriophage lytic enzyme," Antimicrob. Agents Chemother. 49: 111-117 (2005).
Fig. 9 illustrates in vivo test results demonstrating the control of GBS colonization in
mice vagina with PlyGBS (SEQ ID NO:1) or PlyGBS90-1 (SEQ ID NO:5). To obtain
the data illustrated in Fig. 9, mice were colonized with GBS vaginally after
synchronization with ft-estradiol valerate. One day after GBS inoculation, three
groups of mice were treated with either buffer (n=10), or 1,500 ug of PlyGBS (SEQ
ID NO:1) (n=10), or 1,500 ug of PlyGBS90-1 (SEQ ID NO:5) (n=10). Each mouse
was swabbed vaginally before treatment (0-hour samples) and after treatment at 2-
to 4-hour intervals (2- and 4-hour samples). The colony counts of vaginal swabs
were averaged for each time interval in the same group and plotted. Error bar
represent the standard error of the mean. As shown in Fig. 9, mice treated with
mutant PlyGBS90-1 (SEQ ID NO:5) showed a statistically significant drop (from 5.54
logs pre-treatment to an average of 1.68 logs after 4hrs post-treatment) compared to
buffer control (p logs to an average of 2.28 logs after 4 hrs post-treatment. Statistical analysis
indicated that the mutant PlyGBS90-1 exhibited a more efficient decrease in GBS
-18-

colonization thatn PlyGBS treatment 4 hours post-treatment (p= 0.0037). Thus, the
mutant PlyGBS90-1 (SEQ ID NO:5) exhibited a more efficient decrease in GBS
colonization.
Variant Polypeptides
[0055] In addition to the lysins encoded by polypeptide sequences of SEQ ID NO:
1, the present disclosure also provides certain variant polypeptides, including
fragments thereof and polypeptides with certain substitutions. The variant
polypeptides may be hyperactive PlyGBS mutant lysins. For example, the variant
polypeptide is a hyperactive PlyGBS mutant lysin selected from the group: PlyGBS
86-6 (SEQ ID NO:2), PlyGBS 80 (SEQ ID NO:3), PlyGBS 90-8 (SEQ ID NO:4),
PlyGBS 90-1 (SEQ ID NO:5), PlyGBS 94 (SEQ ID NO:8) and PlyGBS 95 (SEQ ID
NO:9). The modified or altered form of the protein or peptides and peptide
fragments, as disclosed, include protein or peptides and peptide fragments that are
chemically synthesized or prepared by recombinant DNA techniques, or both. These
techniques include, for example, chimerization and shuffling. When the protein or
peptide is produced by chemical synthesis, it is preferably substantially free of
chemical precursors or other chemicals, i.e., it is separated from chemical precursors
or other chemicals that are involved in the synthesis of the protein. Accordingly such
preparations of the protein have less than about 30%, 20%, 10%, 5% (by dry weight)
of chemical precursors or compounds other than the polypeptide of interest.
[0056] A "variant polypeptide sequence phage associated lytic enzyme" may be
an active lytic enzyme polypeptide having at least about 80% amino acid sequence
identity with a full-length native sequence lytic enzyme polypeptide sequence as
disclosed. Such lytic enzyme polypeptide variants include, for example, lytic enzyme
polypeptides where one or more amino acid residues are added, or deleted, at the
N- or C-terminus of the full-length native amino acid sequence. A lytic enzyme
polypeptide variant will have at least about 80% amino acid sequence identity, and
may have at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%,
91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.5% amino acid sequence
identity with a full-length native sequence lytic enzyme polypeptide sequence, a lytic
enzyme polypeptide sequence iacking the signal peptide,an extracellular domain of a
-19-

lytic enzyme polypeptide, with or without the signal peptide, or any other specifically
defined fragment of a full-length lytic enzyme polypeptide sequence as disclosed.
Lytic enzyme variant polypeptides may be at least about 10 amino acids in length,
often at least about 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200 or 300 amino acids
in length, or more.
[0057J Such phage associated lytic enzyme variants include, for instance, lytic
enzyme polypeptides where one or more amino acid residues are added, or deleted
at the N or C terminus of the sequence of SEQ ID Nos. 1-9. In an example, one or
more amino acids are substituted, deleted, and/or added to any position(s) in the
sequence, or sequence portion.
[0058] "Percent amino acid sequence identity" with respect to the phage
associated lytic enzyme sequences identified is defined as the percentage of amino
acid residues in a candidate sequence that are identical with the amino acid residues
in the phage associated lytic enzyme sequence, after aligning the sequences in the
same reading frame and introducing gaps, if necessary, to achieve the maximum
percent sequence identity, and not considering any conservative substitutions as
part of the sequence identity. Alignment for purposes of determining percent amino
acid sequence identity can be achieved in various ways that are within the skill in the
art, for example, using publicly available computer software such as blast software.
[0059] Polypeptide alignment for purposes of determining percent amino acid
sequence identity can be achieved in various ways that are within the skill in the art,
for example using publicly available computer software such as BLAST, BLAST-2,
ALIGN or Megalign (DNASTAR) software. Those skilled in the art can determine
appropriate parameters for measuring alignment, including any algorithms needed to
achieve maximal alignment over the full length of the sequences being compared.
[0060] The percent amino acid sequence identity values also may be obtained as
described below by using the WU-BLAST-2 computer program (Altschul et ai,
Methods in Enzymology 266:460-480 (1996)). Most of the WU-BLAST-2 search
parameters are set to the default values. Those not set to default values are set with
the following values: overlap span=1, overlap fraction=0.125, word threshold (T)=11,
and scoring matrix=BLOSUM62. When WU-BLAST-2 is employed, a percent amino
acid sequence identity value is determined by dividing (a) the number of matching
-20-

identical amino acid residues between the amino acid sequence of the lytic enzyme
polypeptide of interest having a sequence derived from the native lytic enzyme
polypeptide and the comparison amino acid sequence of interest (i.e., the sequence
against which the lytic enzyme polypeptide of interest is being compared which may
be a lytic enzyme variant polypeptide) as determined by WU-BLAST-2 by (b) the
total number of amino acid residues of the lytic enzyme polypeptide of interest. For
example, in the statement "a polypeptide comprising an the amino acid sequence A
which has or having at least 80% amino acid sequence identity to the amino acid
sequence B", the amino acid sequence A is the comparison amino acid sequence of
interest and the amino acid sequence B is the amino acid sequence of the lytic
enzyme polypeptide of interest.
[0061] Percent amino acid sequence identity also may be determined using the
sequence comparison program NCBI-BLAST2 (Altschul et al., Nucleic Acids Res.
25:3389-3402 (1997)). The NCBI-BLAST2 sequence comparison program may be
downloaded from http://www.ncbi.nlm.nih.gov. NCBI-BLAST2 uses several search
parameters, where all of those search parameters are set to default values including,
for example, unmask=yes, strand=all, expected occurrences=10, minimum low
complexity length=15/5, multi-pass e-value=0.01, constant for multi-pass=25, dropoff
for final gapped alignment=25 and scoring matrix=BLOSUM62.
[0062] In situations where NCBI-BLAST2 is employed for amino acid sequence
comparisons, the percent amino acid sequence identity of a given amino acid
sequence A to, with, or against a given amino acid sequence B (which can
alternatively be phrased as a given amino acid sequence A that has or comprises a
certain percent amino acid sequence identity to, with, or against a given amino acid
sequence B) is calculated as follows:
100 times the fraction X/Y
where X is the number of amino acid residues scored as identical matches by the
sequence alignment program NCBI-BLAST2 in that program's alignment of A and B,
and where Y is the total number of amino acid residues in B. It will be appreciated-
that where the length of amino acid sequence A is not equal to the length of amino
acid sequence B, the percent amino acid sequence identity of A to B will not equal
the percent amino acid sequence identity of B to A.
-21-

Lysin Fragments
[0063] In some examples, biologically active fragments of the lysins, including the
polypeptide sequences such as SEQ ID NO: 1 or variants therof described, are
provided. The variant polypeptides include hyperactive PlyGBS mutant lysins. The
variant polypeptide may a hyperactive PlyGBS mutant lysin selected from the group
consisting of: PlyGBS 86-6 (SEQ ID NO:2), PlyGBS 80 (SEQ ID NO:3), PlyGBS 90-
8 (SEQ ID NO:4), PlyGBS 90-1 (SEQ ID NO:5), PlyGBS 94 (SEQ ID NO:8) and
PlyGBS 95 (SEQ ID NO:9). A "fragment" may include a variant polypeptide having
an amino acid sequence that entirely is the same as part but not all of the amino acid
sequence of the aforementioned polypeptides. A fragment may be "free-standing,"
or comprised within a larger polypeptide of which they form a part or region, most
preferably as a single continuous region, a single larger polypeptide.
[0064] Biologically active portions of a protein or peptide fragment of the
examples, as described, include polypeptides comprising amino acid sequences
sufficiently identical to or derived from the amino acid sequence of the phage protein
of the disclosure, which include fewer amino acids than the full length protein of the
phage protein and exhibit at least one activity of the corresponding full length protein.
Typically, biologically active portions comprise a domain or motif with at least one
activity of the corresponding protein. A biologically active portion of a protein or
protein fragment of the disclosure can be a polypeptide which is, for example, 10,25,
50, 100 less or more amino acids in length. Moreover, other biologically active
portions, in which other regions of the protein are deleted, or added can be prepared
by recombinant techniques and evaluated for one or more of the functional activities
of the native.form of a polypeptide.
[0065] Fragments may include, for example, truncation polypeptides having a
portion of an amino acid sequence corresponding to (e.g., 50% sequence identity, at
least 60%, at least 70% sequence identity, at least 80% sequence identity, at least
95% sequence identity, at least 97% sequence identity or at least or even 98%
sequence identity of at least 50 amino acid long region of the Natural Binding
Region, or of variants, such as a continuous series of residues that includes the
amino terminus, or a continuous series of residues that includes the carboxyl
-22-

terminus. Degradation forms of the polypeptides in a host cell also also are
provided. Further provided are fragments characterized by structural or functional
attributes such as fragments that comprise alpha-helix and alpha-helix forming
regions, beta-sheet and beta-sheet-forming regions, turn and turn-forming regions,
coil and coil-forming regions, hydrophilic regions, hydrophobic regions, alpha
amphipathic regions, beta amphipathic regions, flexible regions, surface-forming
regions, substrate binding region, and high antigenic index regions.
[0066] Also provided are fragments that have binding activities of at least 106,
107, 108 or 109 against GBS bacteria, including those with a similar activity or an
improved activity, or with a decreased undesirable activity. Also advantageous are
conjugates of binding site and a detectable tag or bacteriocidal tag that confers such
desirable clinical function whereby the binding region specifically binds to a bacterial
wall.
[0067] Variants that are fragments of the polypeptides of the disclosure may be
employed for producing the corresponding full-length polypeptide by peptide
synthesis; therefore, these variants may be employed as intermediates for producing
the full-length polypeptides of examples of the disclosure.
[0068] Lytic enzyme peptide fragments may be prepared by any of a number of
conventional techniques. Desired peptide fragments may be chemically synthesized
An alternative approach involves generating lytic enzyme fragments by enzymatic
digestion, e.g., by treating the protein with an enzyme known to cleave proteins at
sites defined by particular amino acid residues, or by digesting the DNA with suitable
restriction enzymes and isolating the desired fragment. Yet another suitable
technique involves isolating and amplifying a DNA fragment encoding a desired
polypeptide fragment, by polymerase chain reaction (PCR). Oligonucleotides that
define the desired termini of the DNA fragment are employed at the 5' and 3' primers
in the PCR. Preferably, lytic enzyme polypeptide fragments share at least one
biological and/or immunological activity with the native lytic enzyme polypeptide
disclosed.
[0069] For example, libraries of fragments of the coding sequence of a
polypeptide of the disclosure can be used to generate a variegated population of
polypeptides for screening and subsequent selection of variants. For example, a
-23-

library of coding sequence fragments can be generated by treating a double
stranded PCR fragment of the coding sequence of interest with a nuclease under
conditions where nicking occurs only about once per molecule, denaturing the
double stranded DNA, renaturing the DNA to form double stranded DNA which can
include sense/antisense pairs from different nicked products, removing single
stranded portions from reformed duplexes by treatment with S1 nuclease, and
ligating the resulting fragment library into an expression vector. By this method, an
expression library can be derived which encodes N terminal and internal fragments
of various sizes of the protein of interest. Several techniques are known in the art for
screening gene products of combinatorial libraries made by point mutations or
truncation, and for screening cDNA libraries for gene products having a selected
property. The most widely used techniques, which are amenable to high through put
analysis, for screening large gene libraries typically include cloning the gene library
into replicable expression vectors, transforming appropriate cells with the resulting
library of vectors, and expressing the combinatorial genes under conditions in which
detection of a desired activity facilitates isolation of the vector encoding the gene
whose product was detected. Recursive ensemble mutagenesis (REM), a technique
which enhances the frequency of functional mutants in the libraries, can be used in
combination with the screening assays to identify variants of a protein of the
disclosure (Arkin and Yourvan (1992) Proc. Natl. Acad. Sci. USA 89:7811 7815;
Delgrave era/. (1993) Protein Engineering 6(3):327 331).
[0070] Immunologically active portions of a protein or peptide fragment can
include regions that bind to antibodies that recognize the phage enzyme. In this
context, the smallest portion of a protein (or nucleic acid that encodes the protein)
may be an epitope that is recognizable as specific for the phage that makes the lysin
protein. Accordingly, the smallest polypeptide (and associated nucleic acid that
encodes the polypeptide) that can be expected to bind antibody and is useful may be
8, 9, 10, 11, 12, 13, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 75, 85, or 100 amino
acids long. Although small sequences as short as 8, 9, 10, 11,12 or 15 amino acids
long reliably comprise enough structure to act as epitopes, shorter sequences of 5,
6, or 7 amino acids long can exhibit epitopic structure in some conditions and have
-24-

value. Thus, the smallest portion of the protein described by SEQ ID No. 1 may
include polypeptides as small as 5, 6, 7, 8, 9, or 10 amino acids long.
[0071] Homologous proteins and nucleic acids can be prepared that share
functionality with such small proteins and/or nucleic acids (or protein and/or nucleic
acid regions of larger molecules) as will be appreciated by a skilled artisan. Such
small molecules and short regions of larger molecules, that may be homologous
specifically are intended as examples, and are not limiting. The homology of such
valuable regions may be at least 50%, 65%, 75%, 85%, at least 90%, 95%, 97%,
98%, or at least 99% compared to SEQ ID No. 1. These percent homology values
do not include alterations due to conservative amino acid substitutions.
[0072] An epitope as described may be used to generate an antibody and also
can be used to detect binding to molecules that recognize the lysin protein. Another
example is a molecule such as an antibody or other specific binder that may be
created through use of an epitope such as by regular immunization or by a phase
display approach where an epitope can be used to screen a library if potential
binders. Such molecules recognize one or more epitopes of lysin protein or a
nucleic acid that encodes lysin protein. An antibody that recognizes an epitope may
be a monoclonal antibody, a humanized antibody, or a portion of an antibody protein.
Desirably the molecule that recognizes an epitope has a specific binding for that
epitope which is at least 10 times as strong as the molecule has for serum albumin.
Specific binding can be measured as affinity (Km). The specific binding may be at
least 102, 103, 104, 105, 106, 107, 108, or even higher than that for serum albumin
under the same conditions.
[0073] In one example, the antibody or antibody fragment is in a form useful for
detecting the presence of the lysin protein. A variety of forms and methods for their
synthesis are known as will be appreciated by a skilled artisan. The antibody may
be conjugated (covalently complexed) with a reporter molecule or atom such as a
fluor, an enzyme that creates an optical signal, a chemilumiphore, a microparticle, or
a radioactive atom. The antibody or antibody fragment may be synthesized in vivo,
after immunization of an animal, for example. The antibody or antibody fragment
may be synthesized via cell culture after genetic recombination. The antibody or
-25-

antibody fragment may be prepared by a combination of cell synthesis and chemical
modification.
Variant polypeptides
[0074] Substitutional variants are those in which at least one residue in the amino
acid sequence has been removed and a different residue inserted in its place. Such
substitutions may be made in accordance with the following Table 2 when it is
desired to finely modulate the characteristics of the protein. Table 2 shows amino
acids which may be substituted for an original amino acid in a protein and which are
regarded as conservative substitutions.
Table 2

Original Residue
Conservative Substitutions
Ala ser
Arg lys
Asn gin, his
Asp glu
Cys ser
Gin asn
Glu asp
Gly pro
His asn; gin
lie leu, val
Leu ile; val
Lys arg; gin; glu
Met leu; ile
Phe met; leu; tyr
Ser thr
Thr ser
Trp tyr
Tyr trp; phe
Val ile; leu
[0075] Substantial changes in function or immunological identity are made by
selecting substitutions that are less conservative than in Table 2, i.e., selecting
residues that differ more significantly in their effect on maintaining: (a) the structure
of the polypeptide backbone in the area of the substitution, for example, as a sheet
-26-

or helical conformation; (b) the charge or hydrophobicity of the molecule at the target
site; or (c) the bulk of the side chain. The substitutions which in general are
expected to produce the greatest changes in protein properties will be those in
which: (a) a hydrophilic residue, e.g., seryl or threonyl, is substituted for (or by) a
hydrophobic residue, e.g., leucyl, isoleucyl, phenylalanyl, valyl or alanyl; (b) a
cysteine or proline is substituted for (or by) any other residue; (c) a residue having an
electropositive side chain, e.g., lysyl, arginyl, or histadyl, is substituted for (or by) an
electronegative residue, e.g., glutamyl or aspartyl; or (d) a residue having a bulky
side chain, e.g., phenylalanine, is substituted for (or by) one not having a side chain,
e.g., glycine.
[0076] The effects of these amino acid substitutions or deletions or additions may
be assessed for derivatives of the lytic protein by analyzing the ability of the
derivative proteins to complement the sensitivity to DNA cross-linking agents
exhibited by phages in infected bacteria hosts. These assays may be performed by
transfecting DNA molecules encoding the derivative proteins into the bacteria as
described above.
[0077] Substantial modifications in function or immunological identity of the lytic
enzyme polypeptide are accomplished by selecting substitutions that differ
significantly in their effect on maintaining (a) the structure of the polypeptide
backbone in the area of the substitution, for example, as a sheet or helical
conformation, (b) the charge or hydrophobicity of the molecule at the target site, or
(c) the bulk of the side chain. Naturally occurring residues are divided into groups
based on common side-chain properties:
(1) hydrophobic: norleucine, met, ala, val, leu, ile;
(2) neutral hydrophilic: cys, ser, thr;
(3) acidic: asp, glu;
(4) basic: asn, gin, his, lys, arg;
(5) residues that influence chain orientation: gly, pro; and
(6) aromatic: trp, tyr, phe.
[0078] Non-conservative substitutions may entail exchanging a member of one of
these classes for another class. Such substituted residues also may be introduced
into the conservative substitution sites or, into the remaining (non-conserved) sites.
-27-

[0079] Polypeptide variations can be made using methods known in the art such
as oligonucleotide-mediated (site-directed) mutagenesis, alanine scanning, and PCR
mutagenesis. Site-directed mutagenesis [Carter et a/., Nucl. Acids Res., 13:4331
(1986); Zoller et a/., Nucl. Acids Res., 10:6487 (1987)], cassette mutagenesis [Wells
et al., Gene, 34:315 (1985)], restriction selection mutagenesis [Wells et a/., Philos.
Trans. R. Soc. London SerA, 317:415 (1986)] or other known techniques can be
performed on the cloned DNA to produce the lytic enzyme variant DNA.
[0080] Scanning amino acid analysis may also be employed to identify one or
more amino acids along a contiguous sequence. For example, scanning amino
acids may be relatively small, neutral amino acids. Such amino acids include
alanine, glycine, serine, and cysteine. Alanine is typically a preferred scanning
amino acid among this group because it eliminates the side-chain beyond the beta-
carbon and is less likely to alter the main-chain conformation of the variant
[Cunningham and Wells, Science. 244: 1081-1085 (1989)]. Alanine is also typically
preferred because it is the most common amino acid. Further, it is frequently found
in both buried and exposed positions [Creighton, The Proteins, (W. H. Freeman &
Co., N.Y.); Chothia, J. Mol. Biol. 150:1 (1976)]. If alanine substitution does not yield
adequate amounts of variant, an isoteric amino acid can be used.
Chimeric Fusion Proteins
[0081] In some examples, a lysin also may be modified to form a chimeric
molecule comprising a lytic enzyme fused to another, heterologous polypeptide or
amino acid sequence. A "chimeric protein" or "fusion protein" comprises all or (for
example, a biologically active) part of a polypeptide of the disclosure operably linked
to a heterologous polypeptide. Chimeric proteins or peptides are produced, for
example, by combining two or more proteins having two or more active sites.
Chimeric protein and peptides can act independently on the same or different
molecules, and hence have a potential to treat two or more different bacterial
infections at the same time. Chimeric proteins and peptides also are used to treat a
bacterial infection by cleaving the cell wall in more than one location.
[0082] In one example, such a chimeric molecule comprises a fusion of the lytic
enzyme with a tag polypeptide which provides an epitope to which an anti-tag
-28-

antibody can selectively bind. The epitope tag is generally placed at the amino- or
carboxyl-terminus of the lytic enzyme. The presence of such epitope-tagged forms
of the lytic enzyme may be detected using an antibody against the tag polypeptide.
Also, provision of the epitope tag enables the lytic enzyme to be readily purified by
affinity purification using an anti-tag antibody or another type of affinity matrix that
binds to the epitope tag. Various tag polypeptides and their respective antibodies
are well known in the art. Examples include poly-histidine (poly-his) or poly-histidine-
glycine (poly-his-gly) tags; the flu HA tag polypeptide and its antibody 12CA5 [Field
et al., Mol. Cell. Biol., 8:2159-2165 (1988)]; the c-myc tag and the 8F9, 3C7, 6E10,
G4, B7 and 9E10 antibodies thereto [Evan et al., Molecular and Cellular Biology,
5:3610-3616 (1985)1; and the Herpes Simplex virus glycoprotein D (gD) tag and its
antibody [Paborsky et al., Protein Engineering: (6):547-553 (1990)].Other tag
polypeptides include the Flag-peptide [Hopp et al., BioTechnology, 6:1204-1210
(1988)]; the KT3 epitope peptide [Martin et al., Science 255:192-194 (1992)]; an cc-
tubulin epitope peptide (Skinner et al., J. Biol. Chem., 266:15163-15166 (1991)1;
and the T7 gene 10 protein peptide tag (Lutz-Freyermuth et al., Proc. Natl. Acad.
Sci. USA, 87:6393-6397 (1990)].
[0083] In an alternative example, the chimeric molecule may comprise a fusion of
the lytic enzyme with an immunoglobulin or a particular region of an immunoglobulin.
For a bivalent form of the chimeric molecule (also referred to as an
"immunoadhesin"), such a fusion could be to the Fc region of an IgG molecule. The
Ig fusions may include the substitution of a soluble (transmembrane domain deleted
or inactivated) form of a lytic enzyme polypeptide in place of at least one variable
region within an Ig molecule. The immunoglobulin fusion may include the hinge,
CH2 and CH3, or the hinge, CH1, CH2 and CH3 regions of an lgG1 molecule. For
the production of immunoglobulin fusions see also U.S. Pat. No. 5,428,130 issued
Jun. 27, 1995.
[0084] In another example, the chimeric protein or peptide contains a
heterologous signal sequence at its N terminus. For example, the native signal
sequence of a polypeptide of the disclosure can be removed and replaced with a
signal sequence from another protein. For example, the gp67 secretory sequence of
the baculovirus envelope protein can be used as a heterologous signal sequence
-29-

(Current Protocols in Molecular Biology, Ausubel et al., eds., John Wiley & Sons,
1992, incorporated herein by reference). Other examples of eukaryotic heterologous
signal sequences include the secretory sequences of melittin and human placental
alkaline phosphatase (Stratagene; La Jolla, California). In yet another example,
useful prokaryotic heterologous signal sequences include the phoA secretory signal
(Sambrook et al., supra) and the protein A secretory signal (Pharmacia Biotech;
Piscataway, New Jersey).
[0085] Another example of a useful fusion protein is a GST fusion protein in which
the polypeptide of the disclosure is fused to the C terminus of a GST sequence.
Such a chimeric protein can facilitate the purification of a recombinant polypeptide of
the disclosure.
[0086] Another example shows an immunoglobulin fusion protein in which all or
part of a polypeptide of the disclosure is fused to sequences derived from a member
of the immunoglobulin protein family. An immunoglobulin fusion protein can be
incorporated into a pharmaceutical composition and administered to a subject to
inhibit an interaction between a ligand (soluble or membrane bound) and a protein
on the surface of a cell (receptor), to thereby suppress signal transduction in vivo.
The immunoglobulin fusion protein can alter bioavailability of a cognate ligand of a
polypeptide of the disclosure. Inhibition of ligand/receptor interaction may be useful
therapeutically, both for treating bacterial associated diseases and disorders for
modulating (i.e., promoting or inhibiting) cell survival. Moreover, an immunoglobulin
fusion protein of the disclosure can be used as an immunogen to produce antibodies
directed against a polypeptide of the disclosure in a subject, to purify ligands and in
screening assays to identify molecules which inhibit the interaction of receptors with
ligands. Chimeric and fusion proteins and peptides of the disclosure can be
produced by standard recombinant DNA techniques.
[0087] In another example, the fusion gene can be synthesized by conventional
techniques, including automated DNA synthesizers. Alternatively, PCR amplification
of gene fragments can be carried out using anchor primers which give rise to
complementary overhangs between two consecutive gene fragments which
subsequently can be annealed and reamplified to generate a chimeric gene
sequence (see, i.e., Ausubel et al., supra). Moreover, many expression vectors are
-30-

commercially available that already encode a fusion moiety (i.e., a GST polypeptide).
A nucleic acid encoding a polypeptide of the disclosure can be cloned into such an
expression vector such that the fusion moiety is linked in frame to the polypeptide of
the disclosure.
Combination with Signal sequences
[0088] A signal sequence of a polypeptide of can facilitate transmembrane
movement of the protein and peptides and peptide fragments of the disclosure to
and from mucous membranes, as well as by facilitating secretion and isolation of the
secreted protein or other proteins of interest. Signal sequences are typically
characterized by a core of hydrophobic amino acids which are generally cleaved
from the mature protein during secretion in one or more cleavage events. Such
signal peptides contain processing sites that allow cleavage of the signal sequence
from the mature proteins as they pass through the secretory pathway. The
described polypeptides can further comprise a signal sequence, as well as to the
signal sequence itself and to the polypeptide in the absence of the signal sequence
(i.e., the cleavage products). In one example, a nucleic acid sequence encoding a
signal sequence of the disclosure can be operably linked in an expression vector to a
protein of interest, such as a protein which is ordinarily not secreted or is otherwise
difficult to isolate. The signal sequence directs secretion of the protein, such as from
an eukaryotic host into which the expression vector is transformed, and the signal
sequence is subsequently or concurrently cleaved. The protein can then be readily
purified from the extracellular medium by art recognized methods. Alternatively, the
signal sequence can be linked to a protein of interest using a sequence, which
facilitates purification, such as with a GST domain.
[0089] In another example, a signal sequence can be used to identify regulatory
sequences, i.e., promoters, enhancers, repressors. Since signal sequences are the
most amino terminal sequences of a peptide, it is expected that the nucleic acids
which flank the signal sequence on its amino terminal side will be regulatory
sequences that affect transcription. Thus, a nucleotide sequence which encodes all
or a portion of a signal sequence can be used as a probe to identify and isolate the
signal sequence and its flanking region, and this flanking region can be studied to
-31-

identify regulatory elements therein. Variants of the polypeptides of the disclosure
can have an altered amino acid sequence and can function as either agonists
(mimetics) or as antagonists. Variants can be generated by mutagenesis, i.e.,
discrete point mutation or truncation. An agonist can retain substantially the same,
or a subset, of the biological activities of the naturally occurring form of the protein.
An antagonist of a protein can inhibit one or more of the activities of the naturally
occurring form of the protein by, for example, competitively binding to a downstream
or upstream member of a cellular signaling cascade which includes the protein of
interest. Thus, specific biological effects can be elicited by treatment with a variant
of limited function. Treatment of a subject with a variant having a subset of the
biological activities of the naturally occurring form of the protein can have fewer side
effects in a subject relative to treatment with the naturally occurring form of the
protein. Variants of a protein of the disclosure which function as either agonists
(mimetics) or as antagonists can be identified by screening combinatorial libraries of
mutants, i.e., truncation mutants, of the protein of the disclosure for agonist or
antagonist activity. In one example, a variegated library of variants is generated by
combinatorial mutagenesis at the nucleic acid level and is encoded by a variegated
gene library. A variegated library of variants can be produced by, for example,
enzymatically ligating a mixture of synthetic oligonucleotides into gene sequences
such that a degenerate set of potential protein sequences is expressible as individual
polypeptides, or alternatively, as a set of larger fusion proteins (i.e., for phage
display). There are a variety of methods which can be used to produce libraries of
potential variants of the polypeptides of the disclosure from a degenerate
oligonucleotide sequence. Methods for synthesizing degenerate oligonucleotides
are known in the art (see, i.e., Narang (1983) Tetrahedron 39:3; Itakura et al. (1984)
Annu. Rev. Biochem. 53:323; Itakura et al. (1984) Science 198:1056; Ike et al.
(1983) Nucleic Acid Res. 11:477, all herein incorporated by reference).
Shuffled enzymes
[0090] Certain examples provide shuffled proteins or peptides comprising one or
more lytic enzyme peptides or variants disclosed, gene products, or peptides for
more than one related phage protein or protein peptide fragments that are randomly
-32-

cleaved and reassembled into a more active or specific protein. Shuffled
oligonucleotides, peptides or peptide fragment molecules are selected or screened
to identify a molecule having a desired functional property. This method is
described, for example, in Stemmer, US Patent No. 6,132,970.(Method of shuffling
polynucleotides); Kauffman, U.S. Patent No 5, 976,862 (Evolution via Condon based
Synthesis) and Huse, U.S. Patent No. 5,808,022 (Direct Codon Synthesis). The
contents of these patents are incorporated herein by reference. Shuffling is used to
create a protein that is 10 to 100 fold more active than the template protein. The
template protein is selected among different varieties of lysin or holin proteins. The
shuffled protein or peptides constitute, for example, one or more binding domains
and one or more catalytic domains. Each binding or catalytic domain is derived from
the same or a different phage or phage protein. The shuffled domains are either
oligonucleotide based molecules, as gene or gene products, that either alone or in
combination with other genes or gene products are translatable into a peptide
fragment, or they are peptide based molecules. Gene fragments include any
molecules of DNA, RNA, DNA RNA hybrid, antisense RNA, Ribozymes, ESTs,
SNIPs and other oligonucleotide based molecules that either alone or in combination
with other molecules produce an oligonucleotide molecule capable or incapable of
translation into a peptide, a
Covalent Modification of Polypeptides
[0091] Other examples provide for covalent modifications of a lytic enzyme, or
fragment or variant thereof. One type of covalent modification includes reacting
targeted amino acid residues of a lytic enzyme polypeptide with an organic
derivatizing agent that is capable of reacting with selected side chains or the N- or C-
terminal residues of the lytic enzyme -Derivatization with bifunctional agents is
useful, for instance, for crosslinking lytic enzyme to a water-insoluble support matrix
or surface for use in the method for purifying anti-lytic enzyme antibodies, and vice-
versa. Commonly used crosslinking agents include, e.g., 1,1-bis(diazoacetyl)-2-
phenylethane, glutaraldehyde, N-hydroxysuccinimide esters, for example, esters with
4-azidosalicylic acid, homobifunctional imidoesters, including disuccinimidyl esters
such as 3,3'-dithiobis(succinimidylpropionate), bifunctional maleimides such as bis-
-33-

N-maleimido-1,8-octane and agents such as methyl-3-[(p-azidophenyl-
)dithiolpropioimidate.
[0092] Other modifications include deamidation of glutaminyl and asparaginyl
residues to the corresponding glutamyl and aspartyl residues, respectively,
hydroxylation of proline and lysine, phosphorylation of hydroxyl groups of seryl or
threonyl residues, methylation of the a -amino groups of lysine, arginine, and
histidine side chains [T. E. Creighton, Proteins: Structure and Molecular Properties,
W. H. Freeman & Co., San Francisco, pp 79-86 (1983)], acetylation of the N-terminal
amine, and amidation of any C-terminal carboxyl group.
[0093] Another type of covalent modification of the lytic enzyme polypeptide
provided comprises altering the native glycosylation pattern of the polypeptide.
Altering the native glycosylation pattern is intended for purposes herein to mean
deleting one or more carbohydrate moieties found in native sequence lytic enzyme
(either by removing the underlying glycosylation site or by deleting the glycosylation
by chemical and/or enzymatic means), and/or adding one or more glycosylation sites
that are not present in the native sequence lytic enzyme. In addition, the phrase
includes qualitative changes in the glycosylation of the native proteins, involving a
change in the nature and proportions of the various carbohydrate moieties present.
[0094] Addition of glycosylation sites to the lytic enzyme polypeptide may be
accomplished by altering the amino acid sequence. The alteration may be made, for
example, by the addition of, or substitution by, one or more serine or threonine
residues to the native sequence lytic enzyme (for O-linked glycosylation sites). The
lytic enzyme amino acid sequence may optionally be altered through changes at the
DNA level, particularly by mutating the DNA encoding the lytic enzyme polypeptide
at preselected bases such that codons are generated that will translate into the
desired amino acids.
[0095] Another means of increasing the number of carbohydrate moieties on the
lytic enzyme polypeptide is by chemical or enzymatic coupling of glycosides to the
polypeptide. Such methods are described in the art, e.g., in WO 87/05330 published
Sep. 11, 1987, and in Aplin and Wriston, CRC Crit. Rev. Biochem., pp. 259-306
(1981).
-34-

[0096] Removal of carbohydrate moieties present on the lytic enzyme polypeptide
may be accomplished chemically or enzymatically or by mutational substitution of
codons encoding for amino acid residues that serve as targets for glycosylation.
Chemical deglycosylation techniques are known in the art and described, for
instance, by Hakimuddin, et a/., Arch. Biochem. Biophys., 259:52 (1987) and by
Edge et a/., Anal. Biochem., 118:131 (1981). Enzymatic cleavage of carbohydrate
moieties on polypeptides can be achieved by the use of a variety of endo- and exo-
glycosidases as described byThotakura etal., Meth. Enzymol., 138:350 (1987).
[0097] Another type of covalent modification of lytic enzyme comprises linking the
lytic enzyme polypeptide to one of a variety of nonproteinaceous polymers, e.g.,
polyethylene glycol (PEG), polypropylene glycol, or polyoxyalkylenes, in the manner
set forth in U.S. Pat. Nos. 4,640,835; 4,496,689; 4,301,144; 4,670,417; 4,791,192 or
4,179,337.
Holin proteins
[0098] Bacterial lysins my optionally comprise or be administered in combination
with holing proteins. Holin proteins may be administered, for example, in
combination with one or more lytic enzyme peptides, or variants or fragments
thereof. Holin proteins produce holes in the cell membrane, also may be used. Holin
proteins, or "holins," can form lethal membrane lesions. Like the lytic proteins, holin
proteins are coded for and carried by a phage. Most holin protein sequences are
short, and overall, hydrophobic in nature, with a highly hydrophilic carboxy terminal
domain. In many cases, the putative holin protein is encoded on a different reading
frame within the enzymatically active domain of the phage. In other cases, holin
protein is encoded on the DNA next or close to the DNA coding for the cell wall lytic
protein. Holin proteins are frequently synthesized during the late stage of phage
infection and found in the cytoplasmic membrane where they cause membrane
lesions.
[0099] Holins can be grouped into two general classes based on primary
structure analysis. Class I holins are usually 95 residues or longer and may have
three potential transmembrane domains. Class II holins are usually smaller, at
approximately 65-95 residues, with the distribution of charged and hydrophobic
-35-

residues indicating two TM domains (Young, et at. Trends in Microbiology v. 8, No. 4,
March 2000). At least for the phages of gram positive hosts, however, the dual
component lysis system may not be universal. Although the presence of holins has
been shown or suggested for several phages, no genes have yet been found
encoding putative holins for all phages. Holins have been shown to be present in
several bacteria, including, for example, lactococcal bacteriophage Tuc2009,
lactococcal NLC3, pneumococcal bacteriophage EJ 1, LactoBacillus gasseri
bacteriophage Nadh, Staphylococcus aureus bacteriophage Twort, Listeria
monocytogenes bacteriophages, pneumococcal phage Cp 1, Bacillus subtillis phage
M29, LactoBac///us delbrueckki bacteriophage LL H lysin, and bacteriophage N11 of
Staphyloccous aureus. (Loessner, etal., Journal of Bacteriology, Aug. 1999, p. 4452
4460).
Polynucleotides
[00100] A lysin may be produced by any number of different methods. The lytic
enzyme is produced by infecting said GBS bacteriawilh the genetic code delivered
by a bacteriophage specific for said GBS bacteria. In another example, the lytic
enzyme is produced by recombinant production from a nucleic acid that comprises a
DNA having the sequence of bases of a polynucleotide sequence coding for one or
more polypeptides of SEQ ID NO: 1 or a sequence that hybridizes with the
complement of bases of a polynucleotide sequence coding for the polypeptide
sequences of SEQ ID NO: 1 under suitable hybridization conditions. The lytic
enzyme may be produced by removing a gene for the lytic enzyme from the phage
genome, introducing said gene into a transfer vector, and cloning said transfer vector
into an expression system, where the transfer vector is a plasmid. The expression
system may be a bacteria, selected from any of the above listed groups, or, from E.
coli. In another expression system production of the enzyme is by cell free
expression system.
[00101] In addition to the full-length native polynucleotide sequences encoding lytic
enzyme polypeptides described, it is contemplated that lytic enzyme variants can be
prepared. The degeneracy of the genetic code further widens the scope of the
examples as it enables major variations in the nucleotide sequence of a DNA
-36-

molecule while maintaining the amino acid sequence of the encoded protein. For
example, a representative amino acid residue is alanine. This may be encoded in
the cDNA by the nucleotide codon triplet GCT. Because of the degeneracy of the
genetic code, three other nucleotide codon triplets-GCT, GCC and GCA--also code
for alanine. Thus, the nucleotide sequence of the gene could be changed at this
position to any of these three codons without affecting the amino acid composition of
the encoded protein or the characteristics of the protein. The genetic code and
variations in nucleotide codons for particular amino acids are well known to the
skilled artisan. Based upon the degeneracy of the genetic code, variant DNA
molecules may be derived from the cDNA molecules disclosed using standard DNA
mutagenesis techniques as described above, or by synthesis of DNA sequences.
DNA sequences which do not hybridize under stringent conditions to the cDNA
sequences disclosed by virtue of sequence variation based on the degeneracy of the
genetic code are herein comprehended by this disclosure.
[0100] Lytic enzyme variants can be prepared, for example, by introducing
appropriate nucleotide changes into the lytic enzyme DNA, and/or by synthesis of
the desired lytic enzyme polypeptide. Those skilled in the art will appreciate that
amino acid changes may alter post-translational processes of the lytic enzyme, such
as changing the number or position of glycosylation sites or altering the membrane
anchoring characteristics.
[0101] One skilled in the art will recognize that the DNA mutagenesis
techniques described here can produce a wide variety of DNA molecules that code
for a bacteriophage lysin specific for GBS bacteriayei that maintain the essential
characteristics of the lytic protein. Newly derived proteins also may be selected in
order to obtain variations on the characteristic of the lytic protein, as will be more
fully described below. Such derivatives include those with variations in amino acid
sequence including minor deletions, additions and substitutions. While the site for
introducing an amino acid sequence variation is predetermined, the mutation per se
does not need to be predetermined. For example, in order to optimize the
performance of a mutation at a given site, random mutagenesis may be conducted at
the target codon or region and the expressed protein variants screened for the
optimal combination of desired activity. Techniques for making substitution
-37-

mutations at predetermined sites in DNA having a known sequence as described
above are well known. Amino acid substitutions are typically of single residues;
insertions usually will be on the order of about from 1 to 10 amino acid residues; and
deletions will range about from 1 to 30 residues. Deletions or insertions may be in
single form, but preferably are made in adjacent pairs, i.e., a deletion of 2 residues or
insertion of 2 residues. Substitutions, deletions, insertions or any combination
thereof may be combined to arrive at a final construct.
[0102] "Percent nucleic acid sequence identity" with respect to the phage
associated lytic enzyme sequences means as the percentage of nucleotides in a
candidate sequence that are identical with the nucleotides in the phage associated
lytic enzyme sequence, after aligning the sequences and introducing gaps, if
necessary, to achieve the maximum percent sequence identity. Alignment for
purposes of determining percent nucleic acid sequence identity can be achieved in
various ways that are within the scope of those skilled in the art, including but not
limited to the use of publicly available computer software.
[0103] In addition to nucleotide sequences that code for lytic enzyme
genetically coded for by a bacteriophage specific for GBS and fragments of those
enzymes, correspondingly provided are the complementary DNA strands of the
cDNA molecule and DNA molecules which hybridize under stringent conditions to
the lytic enzyme cDNA molecule or its complementary strand. Such hybridizing
molecules include DNA molecules differing only by minor sequence changes,
including nucleotide substitutions, deletions and additions. Also contemplated by this
disclosure are isolated oligonucleotides comprising at least a segment of the cDNA
molecule or its complementary strand, such as oligonucleotides which may be
employed as effective DNA hybridization probes or primers useful in the polymerase
chain reaction. Hybridizing DNA molecules and variants on the lytic enzyme cDNA
may readily be created by standard molecular biology techniques.
[0104] A large variety of isolated cDNA sequences that encode phage
associated lysing enzymes and partial sequences that hybridize with such gene
sequences are useful for recombinant production of the lysing enzyme.
Representative nucleic acid sequences in this context are polynucleotide sequences
coding for the polypeptides of SEQ ID NOS:1-9, sequence and sequences that
-38-

hybridize, under stringent conditions, with complementary sequences of the DNA
encoding the these polypeptide sequences. Still further variants of these sequences
and sequences of nucleic acids that hybridize with those shown in the Figures also
are contemplated for use in production of lysing enzymes according to the
disclosure, including natural variants that may be obtained.
[0105] The detection of specific DNA mutations may be achieved by methods
such as hybridization using specific oligonucleotides (Wallace et al. (1986). Cold
Spring Harbor Symp. Quant. Biol. 51:257-261), direct DNA sequencing (Church and
Gilbert (1988). Proc. Natl. Acad. Sci. USA 81:1991-1995), the use of restriction
enzymes (Flavell et al. (1978). Cell 15:25), discrimination on the basis of
electrophoretic mobility in gels with denaturing reagent (Myers and Maniatis (1986).
Cold Spring Harbor Symp. Quant. Biol. 51:275-284), RNase protection (Myers et al.
(1985). Science 230:1242), chemical cleavage (Cotton et al. (1985). Proc. Natl.
Acad. Sci. USA 85:4397-4401) (incorporated herein by reference), and the ligase-
mediated detection procedure (Landegren etai, 1988).
[0106] Many of the contemplated variant DNA molecules include those
created by standard DNA mutagenesis techniques, such as M13 primer
mutagenesis. Details of these techniques are provided in Sambrook et al. (1989) In
Molecular Cloning: A Laboratory Manual, Cold Spring Harbor, N.Y. (incorporated
herein by reference). By the use of such techniques, variants may be created which
differ in minor ways from those disclosed. DNA molecules and nucleotide
sequences which are derivatives of those specifically disclosed and which differ from
those disclosed by the deletion, addition or substitution of nucleotides while still
encoding a protein which possesses the functional characteristic of the BSMR
protein are contemplated by the disclosure. Also included are small DNA molecules
which are derived from DNA molecules encoding all or part of the disclosed peptide
sequences, or variants thereof. Such small DNA molecules include oligonucleotides
suitable for use as hybridization probes or polymerase chain reaction (PCR) primers.
As such, these small DNA molecules will comprise at least a segment of a lytic
enzyme genetically coded for by a bacteriophage specific for GBS bacteria and, for
the purposes of PCR, will comprise at least a 10-15 nucleotide sequence and, more
preferably, a 15-30 nucleotide sequence of the gene. DNA molecules and
-39-

nucleotide sequences which are derived from the disclosed DNA molecules as
described above also may be defined as DNA sequences which hybridize under
stringent conditions to the DNA sequences disclosed, or fragments thereof.
[0107] Oligonucleotides specific to normal or mutant sequences are
chemically synthesized using commercially available machines, labeled radioactively
with isotopes (such as 32P) or non-radioactively (with tags such as biotin (Ward and
Langer etal. Proc. Natl. Acad. Sci. USA 78:6633-6657 1981) (incorporated herein by
reference), and hybridized to individual DNA samples immobilized on membranes or
other solid supports by dot-blot or transfer from gels after electrophoresis. The
presence or absence of these specific sequences are visualized by methods such as
autoradiography or fluorometric or colorimetric reactions (Gebeyehu et al. Nucleic
Acids Res. 15:4513-4534 1987) (incorporated herein by reference).
[0108] Sequence differences between normal and mutant forms of the gene
also may be revealed by the direct DNA sequencing method of Church and Gilbert
(1988) (incorporated herein by reference). Cloned DNA segments may be used as
probes to detect specific DNA segments. The sensitivity of this method is greatly
enhanced when combined with PCR (Stoflet et al. Science 239:491-494, 1988)
(incorporated herein by reference). In this approach, a sequencing primer which lies
within the amplified sequence is used with double-stranded PCR product or single-
stranded template generated by a modified PCR. The sequence determination is
performed by conventional procedures with radiolabeled nucleotides or by automatic
sequencing procedures with fluorescent tags. Such sequences are useful for
production of lytic enzymes according to examples described.
[0109] Hybridization conditions corresponding to particular degrees of
stringency vary depending upon the nature of the hybridization method of choice and
the composition and length of the hybridizing DNA used. Generally, the temperature
of hybridization and the ionic strength (especially the sodium ion concentration) of
the hybridization buffer will determine the stringency of hybridization. Calculations
regarding hybridization conditions required for attaining particular degrees of
stringency are discussed by Sambrook et al. (1989), In Molecular Cloning: A
Laboratory Manual, Cold Spring Harbor, N.Y., chapters 9 and 11, (herein
incorporated by reference).
-40-

[0110] An example of such calculation is as follows: A hybridization
experiment may be performed by hybridization of a DNA molecule (for example, a
natural variation of the lytic enzyme genetically coded for by a bacteria specific for
GBS bacteria) to a target DNA molecule. A target DNA may be, for example, the
corresponding cDNA which has been electrophoresed in an agarose gel and
transferred to a nitrocellulose membrane by Southern blotting (Southern (1975). J.
Mol. Biol. 98:503), a technique well known in the art and described in Sambrook et
a/. (1989) In Molecular Cloning: A Laboratory Manual, Cold Spring Harbor, N.Y.
(incorporated herein by reference). Hybridization with a target probe labeled with
isotopic P (32) labeled-dCTP is carried out in a solution of high ionic strength such
as 6 times SSC at a temperature that is 20-25 degrees Celsius below the melting
temperature, Tm, (described infra). For such Southern hybridization experiments
where the target DNA molecule on the Southern blot contains 10 ng of DNA or more,
hybridization is carried out for 6-8 hours using 1-2 ng/ml radiolabeled probe (of
specific activity equal to 109 CPM/mug or greater). Following hybridization, the
nitrocellulose filter is washed to remove background hybridization. The washing
conditions are as stringent as possible to remove background hybridization while
retaining a specific hybridization signal. The term "Tm" represents the temperature
above which, under the prevailing ionic conditions, the radiolabeled probe molecule
will not hybridize to its target DNA molecule.
[0111] The Tm of such a hybrid molecule may be estimated from the following
equation: Tm =81.5 degrees C -16.6log10 of sodium ion concentration)
+0.41(%G+C)-0.63(% formamide)-(600/l) where l=the length of the hybrid in base
pairs. This equation is valid for concentrations of sodium ion in the range of 0.01 M
to 0.4M, and it is less accurate for calculations of Tm in solutions of higher sodium
ion concentration (Bolton and McCarthy (1962). Proc. Natl. Acad. Sci. USA 48:1390)
(incorporated herein by reference). The equation also is valid for DNA having G+C
contents within 30% to 75%, and also applies to hybrids greater than 100
nucleotides in length. The behavior of oligonucleotide probes is described in detail in
Ch. 11 of Sambrook et a/. (1989), In Molecular Cloning: A Laboratory Manual, Cold
Spring Harbor, N.Y. (incorporated herein by reference).
-41-

[0112] Thus, by way of example, of a 150 base pair DNA probe derived from
the first 150 base pairs of the open reading frame of a cDNA having a % GC=45%, a
calculation of hybridization conditions required to give particular stringencies may be
made as follows:
[0113] Assuming that the filter will be washed in 0.3 X SSC solution following
hybridization, sodium ion =0.045M; % GC=45%; Formamide concentration^ 1=150
base pairs (see equation in Sambrook et al.) and so Tm =74.4 degrees C. The Tm
of double-stranded DNA decreases by 1-1.5 degrees C with every 1% decrease in
homology (Bonner et al. (1973). J. Mol. Biol. 81:123). Therefore, for this given
example, washing the filter in 0.3 times SSC at 59.4-64.4 degrees C will produce a
stringency of hybridization equivalent to 90%; DNA molecules with more than 10%
sequence variation relative to the target BSMR cDNA will not hybridize.
Alternatively, washing the hybridized filter in 0.3 times SSC at a temperature of 65.4-
68.4 degrees C will yield a hybridization stringency of 94%; DNA molecules with
more than 6% sequence variation relative to the target BSMR cDNA molecule will
not hybridize. The above example is given entirely by way of theoretical illustration.
One skilled in the art will appreciate that other hybridization techniques may be
utilized and that variations in experimental conditions will necessitate alternative
calculations for stringency.
[0114] In some examples, stringent conditions may be defined as those under
which DNA molecules with more than 25% sequence variation (also termed
"mismatch") will not hybridize. In one example, stringent conditions are those under
which DNA molecules with more than 15%, 10% or preferably 6% mismatch will not
hybridize.
[0115] "Stringency" of hybridization reactions is readily determinable by one of
ordinary skill in the art, and generally is an empirical calculation dependent upon
probe length, washing temperature, and salt concentration. In general, longer
probes require higher temperatures for proper annealing, while shorter probes need
lower temperatures. Hybridization generally depends on the ability of denatured
DNA to reanneal when complementary strands are present in an environment below
their melting temperature. The higher the degree of desired homology between the
probe and hybridizable sequence, the higher the relative temperature which can be
-42-

used. As a result, it follows that higher relative temperatures would tend to make the
reaction conditions more stringent, while lower temperatures less so. For additional
details and explanation of stringency of hybridization reactions, see Ausubel et a/.,
Current Protocols in Molecular Biology, Wiley Interscience Publishers, (1995).
[0116] "Stringent conditions" or "high stringency conditions", as defined
herein, may be identified by those that: (1) employ low ionic strength and high
temperature for washing, for example 0.015 M sodium chloride/0.0015 M sodium
citrate/0.1% sodium dodecyl sulfate at 50°C; (2) employ during hybridization a
denaturing agent, such as formamide, for example, 50% (v/v) formamide with 0.1%
bovine serum albumin/0.1% Ficoli/0.1% polyvinylpyrrolidone/50 mM sodium
phosphate buffer at pH 6.5 with 750 mM sodium chloride, 75 mM sodium citrate at
42°C; or (3) employ 50% formamide, 5XSSC (0.75 M NaCI, 0.075 M sodium citrate),
50 mM sodium phosphate (pH 6.8), 0-1% sodium pyrophosphate, 5XDenhardfs
solution, sonicated salmon sperm DNA (50 Dg/ml), 0.1% SDS, and 10% dextran
sulfate at 42°C, with washes at 42°C. in 0.2XSSC (sodium chloride/sodium citrate)
and 50% formamide at 55° C, followed by a high-stringency wash consisting of
0.1XSSC containing EDTA at 55°C.
[0117] "Moderately stringent conditions" may be identified as described by
Sambrook et a/., Molecular Cloning: A Laboratory Manual, New York: Cold Spring
Harbor Press, 1989, and include the use of washing solution and hybridization
conditions (e.g., temperature, ionic strength and % SDS) less stringent that those
described above. An example of moderately stringent conditions is overnight
incubation at 37°C. in a solution comprising: 20% formamide, 5XSSC (150 mM NaCI,
15 mM trisodium citrate), 50 mM sodium phosphate (pH 7.6), 5XDenhardt's solution,
10% dextran sulfate, and 20 mg/ml denatured sheared salmon sperm DNA, followed
by washing the filters in Ltimes.SSC at about 37-50°C. The skilled artisan will
recognize how to adjust the temperature, ionic strength, etc. as necessary to
accommodate factors such as probe length and the like.
-43-

Vectors/host cells expressing polynucleotides for lysins
[0118] Vectors that comprise a polynucleotide or polynucleotides encoding
one of the lysin polypeptide sequences described, or variants or fragments thereof,
are also provided, including vectors formed from just the binding region, or as much
as the entire lysin protein or ligation/conjugate of binding region with other protein.
Other examples concern host cells that are genetically engineered with vectors of
the disclosure and the production of polypeptides of the disclosure by recombinant
techniques. Cell-free translation systems may also be employed to produce such
proteins using RNAs derived from the DNA constructs of the disclosure.
[0119] For recombinant production, host cells can be genetically engineered
to incorporate expression systems or portions thereof or polynucleotides of the
disclosure. Introduction of a polynucleotide into the host cell can be effected by
methods described in many standard laboratory manuals, such as Davis et al.,
BASIC METHODS IN MOLECULAR BIOLOGY, (1986) and Sambrook et al.,
MOLECULAR CLONING: A LABORATORY MANUAL, 2nd Ed., Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, N.Y. (1989), such as, calcium phosphate
transfection, DEAE-dextran mediated transfection, transvection, microinjection,
cationic lipid-mediated transfection, electroporation, transduction, scrape loading,
ballistic introduction and infection.
[0120] Representative examples of appropriate hosts include bacterial cells,
such as Streptococci, Staphylococci, Enterococci E. coli, Streptomyces and Bacillus
subtilis cells; fungal cells, such as yeast cells and Aspergillus cells; insect cells such
as Drosophila S2 and Spodoptera Sf9 cells; animal cells such as CHO, COS, HeLa,
C127, 3T3, BHK, 293 and Bowes melanoma cells; and plant cells.
[0121] A great variety of expression systems can be used to produce the
polypeptides of the disclosure. Such vectors include, among others, chromosomal,
episomal and virus-derived vectors, e.g., vectors derived from bacterial plasmids,
from bacteriophage, from transposons, from yeast episomes, from insertion
elements, from yeast chromosomal elements, from viruses such as baculoviruses,
papova viruses, such as SV40, vaccinia viruses, adenoviruses, fowl pox viruses,
pseudorabies viruses and retroviruses, and vectors derived from combinations
thereof, such as those derived from plasmid and bacteriophage genetic elements,
-44-

such as cosmids and phagemids. The expression system constructs may contain
control regions that regulate as well as engender expression. Generally, any system
or vector suitable to maintain, propagate or express polynucleotides and/or to
express a polypeptide in a host may be used for expression in this regard. The
appropriate DNA sequence may be inserted into the expression system by any of a
variety of well-known and routine techniques, such as, for example, those set forth in
Sambrook et a/., MOLECULAR CLONING, A LABORATORY MANUAL, (supra).
[0122] For secretion of the translated protein into the lumen of the
endoplasmic reticulum, into the periplasmic space or into the extracellular
environment, appropriate secretion signals may be incorporated into the expressed
polypeptide. These signals may be endogenous to the polypeptide or they may be
heterologous signals.
[0123] Polypeptides of the disclosure can be recovered and purified from
recombinant cell cultures by well-known methods including ammonium sulfate or
ethanol precipitation, acid extraction, anion or cation exchange chromatography,
phosphocellulose chromatography, hydrophobic interaction chromatography, affinity
chromatography, hydroxylapatite chromatography, and lectin chromatography. High
performance liquid chromatography is also employed for purification. Well known
techniques for refolding protein may be employed to regenerate active conformation
when the polypeptide is denatured during isolation and or purification.
[0124] Nucleic acid is "operably linked" when it is placed into a functional
relationship with another nucleic acid sequence. For example, DNA for a
presequence or secretory leader is operably linked to DNA for a polypeptide if it is
expressed as a preprotein that participates in the secretion of the polypeptide; a
promoter or enhancer is operably linked to a coding sequence if it affects the
transcription of the sequence; or a ribosome binding site is operably linked to a
coding sequence if it is positioned so as to facilitate translation. Generally, "operably
linked" means that the DNA sequences being linked are contiguous, and, in the case
of a secretory leader, contiguous and in reading phase. However, enhancers do not
have to be contiguous. Linking is accomplished by ligation at convenient restriction
sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are
used in accordance with conventional practice.
-45-

Diagnostic Assays
[0125] Detection assays advantageously utilize a heterogeneous format
where a binding reaction between a conjugated binding agent and an analyte occurs
followed by a wash step to remove unbound conjugated binding agent. For
example, gold sol particles may be prepared with protein that comprises the binding
region with the binding protein immobilized on the particle surfaces. As binding
occurs between the protein and bacteria, the particles merge and form a colored
product. Analogously, the binding protein may be complexed, for example covalently
with an enzyme such as beta galactosidase, peroxidase, or horseradish peroxidase.
After wash, the remaining bound enzyme can be detected by adding a substrate
such as a fluorogenic or chemilumigenic substrate. The binding protein may be
complexed with any other reagent that can make a signal such as a rare earth fluor
and detected by time resolved fluorescence, a radioactive material and detected by
radioactivity measurement, or a regular fluorescent tag, and detected by
fluorescence.
[0126] The conjugation of the binding region with a detectable tag may be
carried out by synthetic chemistry or a biological process. For example, a DNA
sequence coding for the binding region or of the entire lysine protein can be linked to
genetic information that encodes a detectable marker such as green fluorescent
protein (GFP) or an enzyme such as alkaline phosphatase. This could be
accomplished by separating the DNA for the binding domain by removing the N-
terminal catalytic domain and replacing it in frame with indicator molecules such as
green flourescent protein (GFP) and purifying the expressed fusion molecule for the
identification of GBS bacteria. Since the binding domain has a similar binding affinity
of an immunoglobulin G molecule, the marked binding domain will effectively identify
GBS bacferiawith little false positive activity. One also could fuse the GFP molecule
or an enzyme at the 5' end of the whole lysin enzyme if necessary, by doing so the
enzymatic domain will be at least partly inactivated, still allowing the binding domain
to function to bind to its substrate in the cell wall.
[0127] The isolated binding domain separated from the catalytic domain may
be expressed, purified and labeled using a number of fluorescent molecules such as
-46-

fluorescein isothiocyanate, rhodamine isothiocyanate and others known by skilled
artisans. The binding domain may be modified with biotin to allow formation of a
biotin-avidin complex after the binding region adheres to the GBS bacfer/afor
identification.
[0128] Other catalytic domains may be added to the binding region. As
exemplified by Diaz ef a/. Proc. Natl. Acad. Sci. U.S.A., 87:8125 (1990) for another
system, the catalytic domain may be replaced with catalytic domains from other
phage lytic enzymes to cleave other bonds in the peptidoglycan cell wall of GBS
bacteria. For example, the portion of the 5' end of the gamma lysin gene that codes
for the N-terminal catalytic domain (an amidase) may be removed and replaced with
the catalytic domain from phage lytic enzymes of other GBS phage and even from
phage of other gram-positive and gram-negative bacteria. These catalytic domains
may be other amidases (which may have higher activity or special features),
muramidases, glucaminidases, or endopeptidases, all of which, when genetically
fused to the binding domain of the gamma lysin will cleave their respective bonds in
the peptidoglycan of the GBS bacteria. In a related example two or three (or more)
tandem catalytic domains of different specificities may be fused (i.e., muramidases-
glucaminidases-amidase) to a single gamma lysin binding domain to cleave these
bonds in the GBS bacter/acell wall peptidoglycan producing a highly active cleaving
enzyme. Navarre (Identification of a D alanyl glycine endopeptidase activity. J Biol
Chem. 1999 May 28;274:15847 56.) has shown that triple enzymatic domains may
exist in bacteriophage lytic enzymes.
[0129] Various conventional linkers can be used, e.g., diisocyanates,
diisothiocyanates, carbodiimides, bis-hydroxysuccinimide esters, maleimide-
hydroxysuccinimide esters, glutaraldehyde and the like, such as a selective
sequential linker such as the anhydride-isothiocyante linker disclosed in U.S. Pat.
No. 4,680,338.
-47-

Therapeutic Compositions
[0130] Lytic enzymes may also be used to provide a prophylactic treatment for
conditions associated with exposure to GBS bacteria, or as a therapeutic treatment
for those who have already become ill from infection. The phage associated lytic
enzymes described are specific for GBS bacteriaand preferably effectively and
efficiently break down the cell wall of the GBS bacteria.
[0131] The lytic enzyme polypeptides described also may be employed as a
therapeutic agent. The lytic enzyme polypeptides of the present invention can be
formulated according to known methods to prepare pharmaceutically useful
compositions, whereby the lytic enzyme product hereof is combined in admixture
with a pharmaceutically acceptable carrier vehicle. Compositions which may be
used for the prophylactic and therapeutic treatment of a GBS ibacferiainfection also
includes the shuffled and/or chimeric enzyme and a means of application (such as a
carrier system or an oral delivery mode) to the mucosal lining of the oral and nasal
cavity, such that the enzyme is put in the carrier system or oral delivery mode to
reach the mucosa lining.
[0132] "Carriers" as used herein include pharmaceutically acceptable carriers,
excipients, or stabilizers which are nontoxic to the cell or mammal being exposed
thereto at the dosages and concentrations employed. Often the physiologically
acceptable carrier is an aqueous pH buffered solution. Examples of physiologically
acceptable carriers include buffers such as phosphate, citrate, and other organic
acids; antioxidants including ascorbic acid; low molecular weight (less than about 10
residues) polypeptide; proteins, such as serum albumin, gelatin, or immunoglobulins;
hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine,
glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and
other carbohydrates including glucose, mannose, or dextrins; chelating agents such
as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such
as sodium; and/or nonionic surfactants such as TWEEN™, polyethylene glycol
(PEG), and PLURONICS™.
[0133] Prior to, or at the time the modified lytic enzyme is put in the carrier
system or oral delivery mode, the enzyme may be in a stabilizing buffer environment
-48-

for maintaining a suitable pH range, such as between about 5.0 and about 8.0,
including a pH of about 5.0, 6.0, 7.0, 8.0 or any pH interval of 0.05 therebetween, or
any interval that is a multiple of 0.05 therebetween, including pH values of 5.2, 6.5,
7.4, 7.5 and 8.5. .
[0134] Therapeutic formulations are prepared for storage by mixing the active
ingredient having the desired degree of purity with optional physiologically
acceptable carriers, excipients or stabilizers (Remington's Pharmaceutical Sciences
16th edition, Osol, A. Ed. (1980)), in the form of lyophilized formulations or aqueous
solutions. Acceptable carriers, excipients or stabilizers are nontoxic to recipients at
the dosages and concentrations employed, and include buffers such as phosphate,
citrate and other organic acids; antioxidants including ascorbic acid; low molecular
weight (less than about 10 residues) polypeptides; proteins, such as serum albumin,
gelatin or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone,
amino acids such as glycine, glutamine, asparagine, arginine or lysine;
monosaccharides, disaccharides and other carbohydrates including glucose,
mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as
mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic
surfactants such as TWEEN™, PLURONICS™ or PEG.
[0135] Any of the carriers for the lytic enzyme may be manufactured by
conventional means. However, if alcohol is used in the carrier, the enzyme should be
in a micelle, liposome, or a "reverse" liposome, to prevent denaturing of the enzyme.
Similarly, when the lytic enzyme is being placed in the carrier, and the carrier is, or
has been heated, such placement should be made after the carrier has cooled
somewhat, to avoid heat denaturation of the enzyme. The carrier preferably is
sterile. One or more lytic enzymes may be added to these substances in a liquid
form or in a lyophilized state, whereupon it will be solubilized when it meets a liquid
body.
Stabilizing buffers
[0136] A stabilizing buffer should allow for the optimum activity of the lysin
enzyme. The buffer may contain a reducing reagent, such as dithiothreitol. The
stabilizing buffer also may be or include a metal chelating reagent, such as
-49-

ethylenediaminetetracetic acid disodium salt, or it also may contain a phosphate or
citrate phosphate buffer, or any other buffer. The DNA coding of these phages and
other phages may be altered to allow a recombinant enzyme to attack one cell wall
at more than two locations, to allow the recombinant enzyme to cleave the cell wall
of more than one species of bacteria, to allow the recombinant enzyme to attack
other bacteria, or any combinations thereof. The type and number of alterations to a
recombinant bacteriophage produced enzyme are incalculable. Any number of
chimeric and shuffled lytic enzymes, alone or along with holin proteins, may be
assembled to treat the exposure to GBS bacteria.
Mucoadhesives
[0137] In some examples, a therapeutic composition comprises a
mucoadhesive and a lytic enzyme, or chimeric and/or shuffled lytic enzymes, or their
peptide fragments when the composition is directed to the mucosal lining to kill
colonizing disease bacteria. The mucosal lining, as disclosed and described,
includes, for example, the upper and lower respiratory tract, eye, buccal cavity, nose,
rectum, vagina, periodontal pocket, intestines and colon. Due to natural eliminating
or cleansing mechanisms of mucosal tissues, conventional dosage forms are not
retained at the application site for any significant length of time.
[0138] For these and other reasons it is advantageous to have materials
which exhibit adhesion to mucosal tissues, to be administered with one or more
phage enzymes and other complementary agents over a period of time. Materials
having controlled release capability are particularly desirable, and the use of
sustained release mucoadhesives has received a significant degree of attention.
[0139] J. R. Robinson (U.S. Pat. No. 4,615,697, incorporated herein by
reference) provides a review of the various controlled release polymeric
compositions used in mucosal drug delivery. The patent describes a controlled
release treatment composition which includes a bioadhesive and an effective amount
of a treating agent. The bioadhesive is a water swellable, but water insoluble
fibrous, crosslinked, carboxy functional polymer containing (a) a plurality of repeating
units of which at least about 80 percent contain at least one carboxyl functionality,
and (b) about 0.05 to about 1.5 percent crosslinking agent substantially free from
-50-

polyalkenyl polyether. While the polymers of Robinson are water swellable but
insoluble, they are crosslinked, not thermoplastic, and are not as easy to formulate
with active agents, and into the various dosage forms, as the copolymer systems of
the present application. Micelles and multi lamellar micelles also may be used to
control the release of enzyme.
[0140] Other approaches involving mucoadhesives which are the combination
of hydrophilic and hydrophobic materials, are known. Orahesive® from E.R. Squibb
& Co is an adhesive which is a combination of pectin, gelatin, and sodium
carboxymethyl cellulose in a tacky hydrocarbon polymer, for adhering to the oral
mucosa. However, such physical mixtures of hydrophilic and hydrophobic
components eventually fall apart. In contrast, the hydrophilic and hydrophobic
domains in the present disclosure produce an insoluble copolymer.
[0141] U.S. Pat. No. 4,948,580, also incorporated by reference, describes a
bioadhesive oral drug delivery system. The composition includes a freeze dried
polymer mixture formed of the copolymer poly(methyl vinyl ether/maleic anhydride)
and gelatin, dispersed in an ointment base, such as mineral oil containing dispersed
polyethylene. U.S. Pat. No. 5,413,792 (incorporated herein by reference) discloses
paste like preparations comprising (A) a paste like base comprising a
polyorganosiloxane and a water soluble polymeric material which are may be
present in a ratio by weight from 3:6 to 6:3, and (B) an active ingredient. U.S. Pat.
No. 5,554,380 claims a solid or semisolid bioadherent orally ingestible drug delivery
system containing a water in oil system having at least two phases. One phase
comprises from about 25% to about 75% by volume of an internal hydrophilic phase
and the other phase comprises from about 23% to about 75% by volume of an
external hydrophobic phase, where the external hydrophobic phase is comprised of
three components: (a) an emulsifier, (b) a glyceride ester, and (c) a wax material.
U.S. Pat. No. 5,942,243 describes some representative release materials useful for
administering antibacterial agents, which disclosure is incorporated by reference.
[0142] A therapeutic composition may contain polymeric mucoadhesives
consisting essentially of a graft copolymer comprising a hydrophilic main chain and
hydrophobic graft chains for controlled release of biologically active agents. The
graft copolymer is a reaction product of (1) a polystyrene macromonomer having an
-51-

ethylenically unsaturated functional group, and (2) at least one hydrophilic acidic
monomer having an ethylenically unsaturated functional group. The graft chains
consist essentially of polystyrene, and the main polymer chain of hydrophilic
monomeric moieties, some of which have acidic functionality. The weight percent of
the polystyrene macromonomer in the graft copolymer is between about 1 and about
20% and the weight percent of the total hydrophilic monomer in the graft copolymer
is between 80 and 99%, and where at least 10% of said total hydrophilic monomer is
acidic, said graft copolymer when fully hydrated having an equilibrium water content
of at least 90%.
[0143] Compositions containing the copolymers gradually hydrate by sorption
of tissue fluids at the application site to yield a very soft jelly like mass exhibiting
adhesion to the mucosal surface. During the period of time the composition is
adhering to the mucosal surface, it provides sustained release of the
pharmacologically active agent, which is absorbed by the mucosal tissue.
[0144] Mucoadhesivity of the compositions of these examples are, to a large
extent, produced by the hydrophilic acidic monomers of the chain in the polystyrene
graft copolymer. The acidic monomers include, but are not limited to, acrylic and
methacrylic acids, 2 acrylamido 2 methyl propane sulfonic acid, 2 sulfoethyl
methacrylate, and vinyl phosphonic acid. Other copolymerizable monomers include,
but are not limited to N,N dimethylacrylamide, glyceryl methacrylate, polyethylene
glycol monomethacrylate, etc.
[0145] The compositions of the disclosure may optionally contain other
polymeric materials, such as poly(acrylic acid), poly, (vinyl pyrrolidone), and sodium
carboxymethyl cellulose plasticizers, and other pharmaceutically acceptable
excipients in amounts that do not cause a deleterious effect upon mucoadhesivity of
the composition. The dosage forms of the compositions of this disclosure can be
prepared by conventional methods.
Pharmaceuticals
[0146] The present disclosure also provides compositions comprising one or
more pharmaceutical agents and one or more lysins. Further provided are methods
-52-

of treatment combining administration of one or more pharmaceutical agents and
one or more lysins administered separately or in combination.
[0147]' Pharmaceuticals that may be used include antimicrobial agents, anti-
inflammatory agents, antiviral agents, local anesthetic agents, corticosteroids,
destructive therapy agents, antifungals, and antiandrogens. Active pharmaceuticals
that may be used in topical formulations include antimicrobial agents, especially
those having anti-inflammatory properties such as dapsone, erythromycin,
minocycline, tetracycline, clindamycin, and other antimicrobials. Weight percentages
for the antimicrobials are from about 0.5% to to about 10%.
[0148] Local anesthetics include tetracaine, tetracaine hydrochloride,
lidocaine, lidocaine hydrochloride, dyclonine, dyclonine hydrochloride, dimethisoquin
hydrochloride, dibucaine, dibucaine hydrochloride, butambenpicrate, and pramoxine
hydrochloride. An exemplary concentration for local anesthetics is about 0.025% to
about 5% by weight of the total composition. Anesthetics such as benzocaine also
may be used at a preferred concentration of about 2% to about 25% by weight.
[0149] Corticosteroids that may be used include betamethasone dipropionate,
fluocinolone actinide, betamethasone valerate, triamcinolone actinide, clobetasol
propionate, desoximetasone, diflorasone diacetate, amcinonide, flurandrenolide,
hydrocortisone valerate, hydrocortisone butyrate, and desonide are recommended at
concentrations of about 0.01% to 1.0% by weight. The concentrations for
corticosteroids such as hydrocortisone or methylprednisolone acetate may be from
about 0.2% to about 5.0% by weight.
[0150] Destructive therapy agents such as salicylic acid or lactic acid also may
be used. A concentration of about 2% to about 40% by weight may be used.
Cantharidin is may be utilized, for example, in a concentration of about 5% to about
30% by weight. Typical antifungals that may be used in topical compositions and
examples of suitable weight concentrations include: oxiconazole nitrate (0.1% to
5.0%), ciclopirox olamine (0.1% to 5.0%), ketoconazole (0.1% to 5.0%), miconazole
nitrate (0.1% to 5.0%), and butoconazole nitrate (0.1% to 5.0%). Other topical
agents may be included to address a variety of topical co-infections that may occur
as will be appreciated by skilled artisans.
-53-

[0151] Typically, treatments using a combination of drugs include antibiotics in
combination with local anesthetics such as polymycin B sulfate and neomycin sulfate
in combination with tetracaine for topical antibiotic gels to provide prophylaxis
against infection and relief of pain. Another example is the use of minoxidil in
combination with a corticosteroid such as betamethasone diproprionate for the
treatment of alopecia ereata. The combination of an anti-inflammatory such as
cortisone with an antifungal such as ketoconazole for the treatment of tinea
infections is also an example.
[0152] The composition may comprise dapsone and ethoxydiglycol, which
allows for an optimized ratio of micro particulate drug to dissolved drug. This ratio
determines the amount of drug delivered, compared to the amount of drug retained
in or above the stratum corneum to function in the supracomeum domain. The
system of dapsone and ethoxydiglycol may include purified water combined with
"CARBOPOL®" gelling polymer, methylparaben, propylparaben, titanium dioxide,
BHA, and a caustic material to neutralize the "CARBOPOL®"
[0153] In order to accelerate treatment of the infection, the therapeutic agent
may further include at least one complementary agent that may also potentiate the
bactericidal activity of the lytic enzyme. The complementary agent can be
erythromycin, clarithromycin, azithromycin, roxithromycin, other members of the
macrolide family, penicillins, cephalosporins, and any combinations thereof in
amounts that are effective to synergistically enhance the therapeutic effect of the
lytic enzyme. Virtually any other antibiotic may be used with the modified lytic
enzyme. Similarly, other lytic enzymes may be included in the carrier to treat other
bacterial infections. Holin proteins may be included in the therapeutic treatment.
[0154] In some examples, a mild surfactant in an amount effective to
potentiate the therapeutic effect of the modified lytic enzyme may be used in or in
combination with a therapeutic composition. Suitable mild surfactants include, inter
alia, esters of polyoxyethylene sorbitan and fatty acids (Tween series), octylphenoxy
polyethoxy ethanol (Triton X series), n Octyl beta.D glucopyranoside, n Octyl betaD
thioglucopyranoside, n Decai beta D glucopyranoside, n Dodecyl betaD
glucopyranoside, and biologically occurring surfactants, e.g., fatty acids, glycerides,
monoglycerides, deoxycholate and esters of deoxycholate.
-54-

Administration of Compositions Comprising Lysins
[0155] Therapeutic compositions comprising one or more lytic enzymes, such
as PlyGBS, or variants or fragments thereof, can be administered to a subject by any
suitable means. Means of application of the lytic enzyme(s) (modified or unmodified)
include, but are not limited to direct, indirect, carrier and special means or any
combination of means. Direct application of the lytic enzyme may be by nasal
sprays, nasal drops, nasal ointments, nasal washes, nasal injections, nasal
packings, bronchial sprays and inhalers, or indirectly through use of throat lozenges,
mouthwashes or gargles, or through the use of ointments applied to the nasal nares,
or any combination of these and similar methods of application. The forms in which
the lytic enzyme may be administered include but are not limited to lozenges,
troches, candies, injectants, chewing gums, tablets, powders, sprays, liquids,
ointments, and aerosols. It is most probable that exposure to the GBS bacteriawiU
be through the nose. It is best to be treated for exposure to the bacteria as soon as
possible.
[0156] When the lytic enzyme(s) is introduced directly by use of nasal sprays,
nasal drops, nasal ointments, nasal washes, nasal injections, nasal packing,
bronchial sprays, oral sprays, and inhalers, the enzyme may be in a liquid or gel
environment, with the liquid acting as the carrier. A dry anhydrous version of the
modified enzyme may be administered by the inhaler and bronchial spray, although
a liquid form of delivery also may be used.
[0157] The lozenge, tablet, or gum into which the enzyme is added may
contain sugar, corn syrup, a variety of dyes, non sugar sweeteners, flavorings, any
binders, or combinations thereof. Similarly, any gum based products may contain
acacia, carnauba wax, citric acid, corn starch, food colorings, flavorings, non sugar
sweeteners, gelatin, glucose, glycerin, gum base, shellac, sodium saccharin, sugar,
water, white wax, cellulose, other binders, and combinations thereof.
[0158] Lozenges may further contain sucrose, corn starch, acacia, gum
tragacanth, anethole, linseed, oleoresin, mineral oil, and cellulose, other binders, and
combinations thereof. In another example of the disclosure, sugar substitutes are
used in place of dextrose, sucrose, or other sugars.
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[0159] As noted above, the enzyme also may be placed in a nasal spray,
where the spray is the carrier. The nasal spray can be a long acting or timed release
spray, and can be manufactured by means well known in the art. An inhalant also
may be used, so that the enzyme may reach further down into the bronchial tract,
including into the lungs.
[0160] Any of the carriers for the lytic enzyme may be manufactured by
conventional means. However, it is preferred that any mouthwash or similar type
products not contain alcohol to prevent denaturing of the enzyme, although enzymes
in liposomes and in other protective modes and forms may be used in alcohol.
Similarly, when the enzyme(s) is (are) being placed in a cough drop, gum, candy or
lozenge during the manufacturing process, such placement should be made prior to
the hardening of the lozenge or candy but after the cough drop or candy has cooled
somewhat, to avoid heat denaturation of the enzyme. The enzyme may also be
sprayed over the surface of the cough drop gum, candy, or lozenge, in high enough
dosages to be effective.
[0161] The enzyme may be added to these substances in a liquid form or in a
lyophilized state, whereupon it will be solubilized when it meets body fluids such as
saliva. The enzyme also may be in a micelle or liposome.
Dosage of Lysins
[0162] The effective dosage rates or amounts of the enzyme(s) to treat the
infection will depend in part on whether the enzyme(s) will be used therapeutically or
prophylactically, the duration of exposure of the recipient to the infectious bacteria,
the size and weight of the individual, etc. The duration for use of the composition
containing the enzyme also depends on whether the use is for prophylactic
purposes, where the use may be hourly, daily or weekly, for a short time period, or
whether the use will be for therapeutic purposes where a more intensive regimen of
the use of the composition may be needed, such that usage may last for hours, days
or weeks, and/or on a daily basis, or at timed intervals during the day. Any dosage
form employed should provide for a minimum number of units for a minimum amount
of time. The concentration of the active units of enzyme that may provide for an
effective amount or dosage of enzyme may be in the range of about 10 units/ml to
-56-

about 500,000 units/ml of fluid in the wet or damp environment of the nasal and oral
passages, and topically as well and possibly in the range of about 10, 20, 30,40, 50,
60, 70, 80, 90, or 100 units/ml to about 50,000 units/ml. Representative values thus
include about 200 units/ml, 300 units/ml, 500 units/ml, 1,000 units/ml, 2,500 units/ml,
5,000 units/ml, 10,000 units/ml, 20,000 units/ml, 30,000 units/ml, and 40,000
units/ml. More specifically, time exposure to the active enzyme units may influence
the desired concentration of active enzyme units per ml. It should be noted that
carriers that are classified as "long" or "slow" release carriers (such as, for example,
certain nasal sprays or lozenges) could possess or provide a lower concentration of
active (enzyme) units per ml, but over a longer period of time, whereas a "short" or
"fast" release carrier (such as, for example, a gargle) could possess or provide a
high concentration of active (enzyme) units per ml, but over a shorter period of time.
The amount of active units per ml and the duration of time of exposure depend on
the nature of infection, whether treatment is to be prophylactic or therapeutic, and
other variables. Thus, the number of dosages will be dependent upon the
circumstances and can range from 1-4 times per day or more, with durations from
one day to multiple weeks. Infections can occur in the skin and thus such
compositions may be formulated for topical application as well, using well known
vehicles such as those described in U.S. Patents 6,056,954 and 6,056,955.
Methods of treatment
[0163] There are a number of advantages to using lytic enzymes to treat
bacterial infections, particularly GBS bacteria. The modular design of lysins, with
their distinct catalytic and binding domains, makes them ideal for domain swapping
experiments in which bacterial specificities and catalytic activities can be improved or
adapted for use against alternate pathogens. Since the catalytic and binding targets
of lysins (peptidoglycan and associated carbohydrates, respectively) are largely
essential for viability, lysin resistance will be rare.
[0164] "Treatment" refers to both therapeutic treatment and prophylactic or
preventative measures, where the object is to prevent or slow down (lessen) the
targeted pathologic condition or disorder. Those in need of treatment include those
-57-

already with the disorder as well as those prone to have the disorder or those in
whom the disorder is to be prevented.
[0165] "Mammal" for purposes of treatment refers to any animal classified as a
mammal, including humans, domestic and farm animals, and zoo, sports, or pet
animals, such as dogs, cats, cattle, horses, sheep, pigs, goats, rabbits, etc.
Preferably, the mammal is human.
[0166] The formulations to be used for in vivo administration are preferably
sterile. This is readily accomplished by filtration through sterile filtration membranes,
prior to or following lyophilization and reconstitution. Therapeutic compositions
herein generally are placed into a container having a sterile access port, for
example, an intravenous solution bag or vial having a stopper pierceable by a
hypodermic injection needle.
[0167] The route of administration is in accord with known methods, e.g.
injection or infusion by intravenous, intraperitoneal, intracerebral, intramuscular,
intraocular, intraarterial or intralesional routes, topical administration, or by sustained
release systems. When treating an bacterial exposure or infection, the lytic enzyme
may be administered in any suitable fashion, including parenterally or through the
oral or nasal cavity.
[0168] Dosages and desired drug concentrations of pharmaceutical
compositions of the present invention may vary depending on the particular use
envisioned. The determination of the appropriate dosage or route of administration
is well within the skill of an ordinary physician. Animal-experiments provide reliable
guidance for the determination of effective doses for human therapy. Interspecies
scaling of effective doses can be performed following the principles laid down by
Mordenti, J. and Chappell, W. "The use of interspecies scaling in toxicokinetics" In
Toxicokinetics and New Drug Development, Yacobi et a/., Eds., Pergamon Press,
New York 1989, pp. 42-96.
[0169] When in vivo administration of a lytic enzyme is employed, normal
dosage amounts may vary from about 10 ng/kg to up to 100 mg/kg of mammal body
weight or more per day, or about 1 p.g/kg/day to 10 mg/kg/day, depending upon the
route of administration. Guidance as to particular dosages and methods of delivery
is also provided below, as well as in the literature. It is anticipated that different
-58-

formulations will be effective for different treatment compounds and different
disorders, that administration targeting one organ or tissue, for example, may
necessitate delivery in a manner different from that to another organ or tissue.
[0170] Where sustained-release administration of a lytic enzyme is desired in
a formulation with release characteristics suitable for the treatment of any disease or
disorder requiring administration of the lytic enzyme, microencapsulation of the lytic
enzyme is contemplated. Microencapsulation of recombinant proteins for sustained
release has been successfully performed with human growth hormone (rhGH),
interferon-(rhlFN-), interleukin-2, and MN rgp120. Johnson et a/., Nat. Med., 2:795-
799 (1996); Yasuda, Biomed. Ther., 27:1221-1223 (1993); Hora et a/.,
Bio/Technology. 8:755-758 (1990); Cleland, "Design and Production of Single
Immunization Vaccines Using Polylactide Polyglycolide Microsphere Systems." in
Vaccine Design: The Subunit and Adjuvant Approach, Powell and Newman, eds,
(Plenum Press: New York, 1995), pp. 439462; WO 97/03692, WO 96/40072, WO
96/07399; and U.S. Pat. No. 5,654,010.
[0171] The sustained-release formulations of these proteins can use poly-
lactic-coglycolic acid (PLGA) polymer due to its biocompatibility and wide range of
biodegradable properties. The degradation products of PLGA, lactic and glycolic
acids, can be cleared quickly within the human body. Moreover, the degradability of
this polymer can be adjusted from months to years depending on its molecular
weight and composition. Lewis, "Controlled release of bioactive agents from
lactide/glycolide polymer," in: M. Chasin and R. Langer (Eds.), Biodegradable
Polymers as Drul: Delivery Systems (Marcel Dekker. New York, 1990), pp. 1-41.
Cutaneous Infection
[0172] Compositions for treating topical infections comprise an effective
amount of at least one lysin produced according to this disclosure and a carrier for
delivering at least one lytic enzyme to the infected skin. The mode of application for
the lytic enzyme includes a number of different types and combinations of carriers
which include, but are not limited to an aqueous liquid, an alcohol base liquid, a
water soluble gel, a lotion, an ointment, a nonaqueous liquid base, a mineral oil
base, a blend of mineral oil and petrolatum, lanolin, liposomes, protein carriers such
-59-

as serum albumin or gelatin, powdered cellulose carmel, and combinations thereof.
A mode of delivery of the carrier containing the therapeutic agent includes, but is not
limited to a smear, spray, a time-release patch, a liquid absorbed wipe, and
combinations thereof. The lytic enzyme may be applied to a bandage either directly
or in one of the other carriers. The bandages may be sold damp or dry, where the
enzyme is in a lyophilized form on the bandage. This method of application is most
effective for the treatment of infected skin.
[0173] The carriers of topical compositions may comprise semi-solid and gel-
like vehicles that include a polymer thickener, water, preservatives, active
surfactants or emulsifiers, antioxidants, sun screens, and a solvent or mixed solvent
system. U.S. Pat. No. 5,863,560 (Osborne) discusses a number of different carrier
combinations that can aid in the exposure of the skin to a medicament.
[0174] Polymer thickeners that may be used include those known to one
skilled in the art, such as hydrophilic and hydroalcoholic gelling agents frequently
used in the cosmetic and pharmaceutical industries. The hydrophilic or
hydroalcoholic gelling agent can comprise, for example, "CARBOPOL®" (S.F.
Goodrich, Cleveland, Ohio), "HYPAN®" (Kingston Technologies, Dayton, N.J.),
"NATROSOL®" (Aqualon, Wilmington, Del.), "KLUCEL®" (Aqualon, Wilmington,
Del.), or "STABILEZE®" (ISP Technologies, Wayne, N.J.). The gelling agent may
comprise between about 0.2% to about 4% by weight of the composition. More
particularly, examples of the compositional weight percent range for "CARBOPOL®"
may be between about 0.5% to about 2%, while the weight percent range for
"NATROSOL®" and "KLUCEL®" may be between about 0.5% to about 4%. A
compositional weight percent range for both "HYPAN®" and "STABILEZE®" may be
between about 0.5% to about 4%.
[0175] "CARBOPOL®" is one of numerous cross-linked acrylic acid polymers
that are given the general adopted name carbomer. These polymers dissolve in
water and form a clear or slightly hazy gel upon neutralization with a caustic material
such as sodium hydroxide, potassium hydroxide, triethanolamine, or other amine
bases. "KLUCEL®" is a cellulose polymer that is dispersed in water and forms a
uniform gel upon complete hydration. Other gelling polymers include
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hydroxyethylcellulose, cellulose gum, MVE/MA decadiene crosspolymer, PVM/MA
copolymer, or a combination thereof.
[0176] Preservatives also may be used in this invention and may comprise, for
example, about 0.05% to 0.5% by weight of the total composition. The use of
preservatives assures that if the product is microbially contaminated, the formulation
will prevent or diminish microorganism growth. Some preservatives useful in this
invention include methylparaben, propylparaben, butylparaben, chloroxylenol,
sodium benzoate, DMDM Hydantoin, 3-!odo-2-Propylbutyl carbamate, potassium
sorbate, chlorhexidine digluconate, or a combination thereof.
[0177] Titanium dioxide may be used as a sunscreen to serve as prophylaxis
against photosensitization. Alternative sun screens include methyl cinnamate.
Moreover, BHA may be used as an antioxidant, as well as to protect ethoxydiglycol
and/or dapsone from discoloration due to oxidation. An alternate antioxidant is BHT.
[0178] In one example, the invention comprises a dermatological composition
having about 0.5% to 10% carbomer and about 0.5% to 10% of a pharmaceutical
that exists in both a dissolved state and a micro particulate state. The dissolved
pharmaceutical has the capacity to cross the stratum corneum, whereas the micro
particulate pharmaceutical does not. Addition of an amine base, potassium,
hydroxide solution, or sodium hydroxide solution completes the formation of the gel.
More particularly, the pharmaceutical may include dapsone, an antimicrobial agent
having anti-inflammatory properties. One exemplayr ratio of micro particulate to
dissolved dapsone is five or less.
[0179] In another example, the invention comprises about 1% carbomer,
about 80-90% water, about 10% ethoxydiglycol, about 0.2% methylparaben, about
0.3% to 3.0% dapsone including both micro particulate dapsone and dissolved
dapsone, and about 2% caustic material. More particularly, the carbomer may
include "CARBOPOL® 980" and the caustic material may include sodium hydroxide
solution.
[0180] In one example, if there is a bacterial infection of the upper respiratory
tract, the infection can be prophylactically or therapeutically treated with a
composition comprising an effective amount of at least one lytic enzyme produced by
a bacteria being infected with a bacteriophage specific for that bacteria, and a carrier
-61-

for delivering the lytic enzyme to a mouth, throat, or nasal passage. The lytic
enzyme may be a lytic enzyme, a chimeric lytic enzyme, and/or shuffled lytic enzyme
which may be used in conjunction with a holin protein or a combination thereof. The
lytic enzyme may be in an environment having a pH which allows for activity of the
lytic enzyme. If an individual has been exposed to someone with the upper
respiratory disorder, the lytic enzyme will reside in the mucosal lining and prevent
any colonization of the infecting bacteria.
Parenteral Administration
[0181] In some examples, an infection may be treated parenterally. The
enzymes which can be used are, as above, lytic enzymes, chimeric lytic, enzymes,
shuffled lytic enzymes, and combinations thereof. The enzymes can be
administered intramuscularly, intravenously, subcutaneously, subdermally, or
combinations thereof. In one example, infections may be treated by injecting into the
patient a therapeutic agent comprising the appropriate shuffled and/or chimeric lytic
enzyme(s) and a carrier for the enzyme. The carrier may be comprised of distilled
water, a saline solution, albumin, a serum, or any combinations thereof. More
specifically, solutions for infusion or injection may be prepared in a conventional
manner, e.g. with the addition of preservatives such as p-hydroxybenzoates or
stabilizers such as alkali metal salts of ethylene diamine tetraacetic acid, which may
then be transferred into fusion vessels, injection vials or ampules. Alternatively, the
compound for injection may be lyophilized either with or without the other ingredients
and be solubilized in a buffered solution or distilled water, as appropriate, at the time
of use. Non aqueous vehicles such as fixed oils, liposomes, and ethyl oleate are
also useful herein. Other phage associated lytic enzymes, along with a holin protein,
may be included in the composition.
[0182] In cases where intramuscular injection is the chosen mode of
administration, an isotonic formulation may be used. Generally, additives for
isotonicity can include sodium chloride, dextrose, mannitol, sorbitol and lactose. In
some cases, isotonic solutions such as phosphate buffered saline are used.
Stabilizers include gelatin and albumin. In some examples, a vasoconstriction agent
is added to the formulation. The pharmaceutical preparations are provided sterile
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and pyrogen free. Generally, as noted above, intravenous injection may be most
appropriate.
[0183] The carrier suitably contains minor amounts of additives such as
substances that enhance isotonicity and chemical stability. Such materials are non
toxic to recipients at the dosages and concentrations employed, and include buffers
such as phosphate, citrate, succinate, acetic acid, and other organic acids or their
salts; antioxidants such as ascorbic acid; low molecular weight (less than about ten
residues) polypeptides, e.g., polyarginine or tripeptides; proteins, such as serum
albumin, gelatin, or immunoglobulins; hydrophilic polymers such as
polyvinylpyrrolidone; glycine; amino acids such as glutamic acid, aspartic acid,
histidine, or arginine; monosaccharides, disaccharides, and other carbohydrates
including cellulose or its derivatives, glucose, mannose, trehalose, or dextrins;
chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; counter
ions such as sodium; non ionic surfactants such as polysorbates, poloxamers, or
polyethylene glycol (PEG); and/or neutral salts, e.g., NaCI, KCI, MgCb, CaCb, etc.
[0184] Glycerin or glycerol (1,2,3 propanetriol) is commercially available for
pharmaceutical use. Glycerin or glycerol may be diluted in sterile water for injection,
or sodium chloride injection, or other pharmaceutically acceptable aqueous injection
fluid, and used in concentrations of 0.1 to 100% (v/v), 1.0 to 50% or about 20%.
[0185] DMSO, is an aprotic solvent with a remarkable ability to enhance
penetration of many locally applied drugs. DMSO may be diluted in sterile water for
injection, or sodium chloride injection, or other pharmaceutically acceptable aqueous
injection fluid, and used in concentrations of 0.1 to 100% (v/v). The vehicle also may
include Ringer's solution, a buffered solution, and dextrose solution, particularly
when an intravenous solution is prepared.
[0186] Prior to, or at the time the enzyme is put in the carrier system or oral
delivery mode, it may be desirable for the enzymes be in a stabilizing buffer
environment, maintaining a pH range between about 5.0 and about 7.5.
[0187] The stabilizing buffer should allow for the optimum activity of the
enzyme. The buffer may be a reducing reagent, such as dithiothreitol. The
stabilizing buffer also may be or include a metal chelating reagent, such as
ethylenediaminetetracetic acid disodium salt, or it also may contain a phosphate or
-63-

citrate phosphate buffer. The buffers found in the carrier can serve to stabilize the
environment for the lytic enzymes.
[0188] The effective dosage rates or amounts of the enzyme to be
administered parenterally, and the duration of treatment will depend in part on the
seriousness of the infection, the weight of the patient, the duration of exposure of the
recipient to the infectious bacteria, the seriousness of the infection, and a variety of a
number of other variables. The composition may be applied anywhere from once to
several times a day, and may be applied for a short or long term period. The usage
may last for days or weeks. Any dosage form employed should provide for a
minimum number of units for a minimum amount of time. The concentration of the
active units of enzyme believed to provide for an effective amount or dosage of
enzyme may be in the range of about 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100
units/ml to about 10,000,000 units/ml of composition, in a range of about 1000
units/ml to about 10,000,000 units/ml, and from about 10,000 to 10,000,000 units/ml.
The amount of active units per ml and the duration of time of exposure depend on
the nature of infection, and the amount of contact the carrier allows the lytic enzyme
to have. It is to be remembered that the enzyme works best when in a fluid
environment. Hence, effectiveness of the enzyme is in part related to the amount of
moisture trapped by the carrier. The concentration of the enzyme for the treatment
is dependent upon the bacterial count in the blood and the blood volume.
[0189] In order to accelerate treatment of the infection, the therapeutic agent
may further include at least one complementary agent which may also potentiate the
bactericidal activity of the lytic enzyme. The complementary agent can be any
antibiotic effective against GBS bacteria. Similarly, other lytic enzymes may be
included to treat other bacterial infections.
[0190] Additionally, a number of methods can be used to assist in transporting
the enzyme across the cell membrane. The enzyme can be transported in a
liposome, with the enzyme be "inserted" in the liposomes by known techniques.
Similarly, the enzyme may be in a reverse micelle. The enzyme may also be
pegylated, attaching the polyethylene glycol to the non-active part of the enzyme.
Alternatively, hydrophobic molecules can be used to transport the enzyme across
-64-

the cell membrane. Finally, the glycosylation of the enzyme can be used to target
specific internalization receptors on the membrane of the cell.
EXAMPLES
Materials
[0191] Restriction endonucleases were obtained from New England Biolabs
(Beverly, MA). All reagents used were purchased from Sigma (St. Louis, MO) unless
otherwise indicated. Bacteria strains and plasmids used in this study are listed in
Table 3 at the end of the Examples.
Example 1: Cloning and sequence alignment of PlyGBS
[0192] Clones of the GBS phage NCTC11261 genomic library were screened
for a possible lysin gene on a GBS NCTC11237 bacterial overlay. The full sequence
of the lysin gene (plyGBS) was obtained by sequencing of the phage NCTC11261
genomic DNA. Similarity searches indicated that at both the nucleotide and amino
acid level this gene was over 90% identical to several lysins from various
streptococcal species, including GBS phage B30 lysin (SEQ ID NO:1)(GenBank
accession number AAN28166), Streptococcus pyogenes M1 phage-associated lysin
(AAK33905), and Streptococcus equi phage-associated protein (AF186180).
[0193] Alignment of the putative PlyGBS protein sequence with pneumococcal
phage Cp-1 lysin (Cpl-1) and staphylococcal phage 187 lysin (Ply187) indicated that
PlyGBS has three different domains. The N-terminal 107 amino acids are 27%
identical to a domain in Ply187 that functions as an endopeptidase. For amino acids
150-394 (central domain), PlyGBS displays 46% identity to the N-terminal
muramidase domain of Cpl-1. Two acidic amino acids, Asp and Glu, are also present
in PlyGBS at positions 158 (Asp) and 185 (Glu).
Example 2: Characterization of PlyGBS
[0194] Based on the deduced amino acid sequence, PlyGBS has a theoretical
pi value (isoelectric point) of 4.88. With 25 mM Tris-HCI (pH 7.4) as elution buffer in
ion-exchange chromatography, the protein was negatively charged and bound to a
positively charged Q-Sepharose anion exchanger. The enzyme was eluted by an
-65-

NaCI gradient and the active fractions were pooled and analyzed by SDS-PAGE.
The major protein band at about 50 KDa correlated with the calculated molecular
mass for PlyGBS (49.6 KDa). The final preparation, estimated to be >95% pure by
scanning densitometry on the Coomassie-stained SDS-PAGE gel, was used for all
subsequent experiments.
[0195] The pH optimum of purified PlyGBS was determined to be around 5.0
with an active pH range between 4.0.0. Gel filtration chromatography of PlyGBS
indicates that the protein functions as a monomer.
Example 3: PlyGBS activity in vitro (optical density In vitro lytic killing assay)
[0196] To test the in vitro PlyGBS activity on various bacterial strains, all
strains were inoculated overnight, subcultured (1:100), and grown to OD6oo= 0.3.
Cells were centrifuged and resuspended in 1/10 volume of phosphate buffer (40 mM,
pH 5.0). 100 microliter aliquots of the bacteria solution (5x108-109 cfu / ml) were
incubated with indicated amounts of PlyGBS at 37 degrees C for 60 min. A
spectrophotometer was used to monitor the lytic activity, measured as the drop in
milliOD6oo per minute (-mOD6oo / min). The initial velocity of this reaction is defined
as the rate of lysis. To determine bacteria viability, cells of GBS strain NCTC11237
from the above assay were centrifuged, diluted and plated on THY agar plates for
cell counts. All experiments were performed in triplicates and control experiments
with the addition of phosphate buffer (pH 5.0) were performed under the same
conditions.
[0197] To determine the PlyGBS activity in vitro against GBS cells, GBS cells
(NCTC 11237, serotype IIIR) were mixed with 40 units of PlyGBS at 37 degrees C
for 60 min. The OD6oo dropped to baseline within 10 min indicating a rapid rate of
cell lysis, which is corroborated by the 2 log decrease in viability observed at 60
minutes. When multiple strains of GBS, representing serotypes la, lb, Ic/ll, MR, IIIR
as well as the predominant serotypes III, and V, were tested for PlyGBS sensitivity
based on lytic activity, a similar velocity of lysis (-mODeoo / min) was observed with
certain strain-to-strain variation.
[0198] In addition to GBS, bacterial strains representing a variety of species
were analyzed to determine their sensitivity to PlyGBS in vitro. Of the tested
streptococcal strains belonging to different Lancefield groups, PlyGBS had
-66-

significant lytic activity against groups A, C, G and L streptococci, with little to no
activity against groups D, E and N. The muralytic activity of the PlyGBS was also
tested against non-Lancefield oral streptococcal species including S. gordonii, S.
oralis, S. salivarius, S. sobrinus, and S. mutans. PlyGBS had medium to low activity
against S. salivarius, S. gordonii and S. mutans, but no activity against the other two
commensal species tested. No lytic activity was observed with two non-
streptococcal gram-positive species, Bacillus cereus and Staphylococcus aureus, or
two vaginal commensal bacteria, Lactobacillus acidophilus and L. crispatus.
[0199] Phase contrast and electron microscopy were used to visualize the lytic
effect of lysin on GBS cells (an example of "lytic activity"). Normally, intact GBS form
short chains in a buffer control. After treatment with PlyGBS lysin, the cells were
lysed, releasing the cytoplasmic contents and becoming opaque by light microscopy.
As seen with other lysins by electron microscopy, a weakness in the cell wall
produced by PlyGBS results in extrusions and rupture of the cytoplasmic membrane,
which appears to be more localized within the septum region of the dividing cells.
Subsequent loss of cytoplasmic contents transforms the cells into empty "cell
ghosts".
Example 4: PlyGBS activity in vivo (mouse model In vivo killing assay)
[0200] Six-week-old BALB/c female mice were purchased from Charles River
Laboratories (Wilmington, MA). Because bacterial colonization in the mouse vaginal
cavity is believed to be more efficient at estrus, the estral cycle of all mice was
synchronized on day 1 by subcutaneous inoculation of 0.1 mg of p-estradiol
valerate. On day 3, thirty mice were anesthetized and inoculated vaginally with ~106
streptomycin resistant GBS NCTC11237 cells using a micropipette (20 |JLI dose in 40
mM phosphate buffer, pH 5.0). On day 4, mice were treated vaginally with 20 p.l
phosphate buffer (pH 5.0) and swabbed with calcium alginate fiber tipped ultrafine
swabs (Fischer, Pittsburgh, PA). The surfaces of THY agar plates containing 5%
sheep blood and streptomycin (200 jig/ml) were streaked with the wet swabs to
determine baseline colonization. Mice were then randomized to be treated vaginally
with either 20 u.l phosphate buffer, pH 5.0 (n=15) or 10 units of PlyGBS lysin (n=15).
At 2 and 4 hrs post-treatment, all mice were swabbed again for titer determination.
-67-

[0201] To test if PlyGBS can be used for postpartum treatment of newborns,
38 mice received an upper respiratory challenge of about 108 StrR GBS
NCTC11237 cells (20 (jJ orally and 20 \i\ to each nostril). The next morning, mice
were oropharyngeally swabbed and baseline colonization was enumerated as
described above. Mice were randomized and administrated orally and nasally with
either 20 \i\ phosphate buffer, pH 5.0 (n=18) or 10 Units PlyGBS lysin (n=20). At 2
and 24 hrs post-treatment, all mice were oropharyngeally swabbed to determine the
bacterial count.
[0202] For statistical analysis, MIXED Model (from SAS Mixed Procedure) was
used to compare the colonization status between groups. A P value considered significant.
[0203] An in vivo killing assay was performed to assess the in vivo lytic activity
of PlyGBS was tested by administering PlyGBS to colonized GBS in a mouse vagina
model. To perform this test, two groups of mice were challenged vaginally with 106
cfu StrR GBS cells. Subsequently, 24 hours later, the vaginal cavities were swabbed
to determine the initial colonization rate (0 hr samples, pre-treatment). The mice
were then treated vaginally with either buffer (n=15) or PlyGBS (n=15) and swabbed
2 hrs and 4 hrs post-treatment. Negligible effect was observed in the buffer control
animals. In contrast, animals treated with a single dose of PlyGBS showed a
significant reduction (approximately 3 log drop) in the bacterial load at both the 2 hr
and 4 hr intervals when compared to buffer control (p [0204] Similarly, two groups of mice were challenged with a total of 108 cfu
StrR GBS delivered orally and nasally to determine if PlyGBS can be used to reduce
colonized GBS in the mouse upper respiratory tract. Mice treated with a single dose
of lysin by the same route exhibited a significant reduction in GBS colonization at
both the 2 hr and 24 hr swabbing intervals when compared to the buffer control
group (p Example 5: PlyGBS Mutant Lysin Production by mutagenesis using an E. coli
mutator strain
[0205] Escherichia coli XL-1 Red strain (Stratagene, Inc., La Jolla, CA, Table
3) was used to generate random mutations in PlyGBS due to deficiency in three
primary DNA repair pathways {muts, mutD, and mut~F) that result in a significantly
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higher mutation rate than the wild-type strain. Plasmid pCQJ67-2 containing the wild
type plyGBS gene was transformed into E. coli XL-1 Red and propagated on LB
plates supplemented with kanamycin (50 ug / ml) 37 degrees C overnight. Colonies
were scraped from the agar plates and subcultured (1:100) for another overnight
growth, allowing mutations to accumulate in the plasmid DNA. The next morning,
the culture was subcultured to grow for an extra 6 hr and plasmid DNA was
prepared. The resultant plasmids containing random mutations were transformed
into the protein expression strain E. coli BL21(DE3) and over 5,000 clones were
screened for lysin activity better than wild type PlyGBS, using the clear zone method
as previously described in Schuch, R., D. Nelson, and V. A. Fischetti, "A bacteriolytic
agent that detects and kills Bacillus anthracis," Nature 418: 884-889 (2002). To
avoid any potential mutations in promoter region, plasmid DNA from clones with
better than wild type activity was prepared and digested with Ncol and Xhol. The
released plyGBS gene fragment was cloned into pET28a and the resultant plasmid
was transform into E. coli BL21(DE3) to confirm the increased lysin activity. DNA
sequence analysis was used to locate the mutations.
Example 6: Gene mutagenesis using error-prone PCR method.
[0206] Another mutagenesis method utilized was the "Diversify PCR Random
Mutagenesis Kit" (BD Bioscience, Palo Alto, CA). The procedure involves
performing a PCR reaction under conditions that reduce the fidelity of nucleotide
incorporation, cloning the resulting PCR fragments, and then screening the library for
novel mutations with improved lysin activity. The PCR mutation rate was chosen
around 2.7 per 1,000 bp by keeping the manganese concentration at 320 uM in the
reaction. Two PCR primers are listed in Cheng, Q.et al., "Removal of group B
streptococci colonizing the vagina and oropharynx of mice with a bacteriophage lytic
enzyme," Antimicrob. Agents Chemother. 49: 111-117 (2005). The PCR product
was digested with Ncol and Xhol, and cloned into pET28a for screening, using the
method mentioned above. Multiple rounds of PCR mutagenesis were performed to
improve the lysin activity.
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Example 7: Construction of plyGBS deletion mutants.
[0207] Several deletion mutants were constructed based on the domain
organization of wild-type plyGBS and a schematic map is shown in Fig. 4. All the
regions were PCR-amplified and cloned into pET28a for protein expression. Mutant
PlyGBS92 (SEQ ID NO:6), expressed from the plasmid pCQJ92 (Table 3), encodes
the putative muramidase domain [amino acid (aa) 150-394]. Mutant PlyGBS93
(SEQ ID NO:7) contains the region of aa 150-443, which deletes the N-terminal
endopeptidase domain. Mutant PlyGBS94 (SEQ ID NO:8), expressed from pCQJ94
(Table 3), contains the first 146 aa that is the putative endopeptidase domain.
Another mutant, PlyGBS95 (SEQ ID NO:9), containing a deletion of the central
muramidase domain (deletion between aa 147-348), was expressed from pCQJ95
constructed by inserting the Hindlll / Xhol digested PCR fragment (C-terminus of
plyGBS gene, bp 1045- 1332) into pCQJ94. All the constructed plasmids for mutant
expression were sequenced to confirm the expected deletion.
Example 8: Comparison of lysin activity and stability.
[0208] To compare the lysin activity of various mutants, clones were grown
and induced for protein over-expression in 10 ml volumes under the same condition
described in Cheng, Q.ef a/., "Removal of group B streptococci colonizing the vagina
and oropharynx of mice with a bacteriophage lytic enzyme,"Antimicrob. Agents
Chemother. 49: 111-117 (2005). Protein crude extracts were used for the in vitro
activity assay. In order to quantitate the protein activity, large batch (1 liter) cultures
were made of each mutant. Because the mutants had a similar pi (Isoelectric point)
to the wild-type enzyme (Table 1), purification was achieved by anion exchange
chromatography as described Cheng, Q.ef a/., "Removal of group B streptococci
colonizing the vagina and oropharynx of mice with a bacteriophage lytic
enzyme,"Antimicrob. Agents Chemother. 49: 111-117 (2005). Active fractions were
pooled and electrophoresed on a 4-20% gradient Tris-HCI pre-cast SDS-PAGE gel
(Bio-Rad, Hercules, CA). Lysin activity was quantitated as described in Cheng, Q.et
a/., "Removal of group B streptococci colonizing the vagina and oropharynx of mice
with a bacteriophage lytic enzyme,"Antimicrob. Agents Chemother. 49: 111-117
(2005). Protein concentration was determined using BCA Protein Assay Kit (Pierce,
Rockford, IL) to calculate the specific activity for each mutant.
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[0209] Because the PlyGBS90-1 (SEQ ID NO:5) and PlyGBS90-8 (SEQ ID
NO:4) mutants obtained from random mutagenesis had a specific activity
significantly higher than wild-type PlyGBS, the stability of the mutants was compared
with wild-type under storage conditions. Fresh-purified wild-type PlyGBS, as well as
two mutants PlyGBS90-1 (SEQ ID NO:5) and PlyGBS90-8 (SEQ ID NO:4), were
stored directly at 4 degrees C or in 25% glycerol at -80 degrees C. An in vitro
activity assay was performed at different time points (0, 20, 40, and 60 days) using a
spectrophotometer to monitor the lytic activity, measured as the drop in milliOD600
per minute (-mOD600 / min). The in vitro activity assay was performed as described
in Cheng, Q.et a/., "Removal of group B streptococci colonizing the vagina and
oropharynx of mice with a bacteriophage lytic enzyme,"Antimicrob. Agents
Chemother. 49:111-117 (2005). The initial velocity of this reaction (Vmax) is defined
as the rate of lysis and was used to compare protein stability at various time
intervals.
Example 9: Characteristics of hyperactive mutant PlyGBS90-1 (SEQ ID NO:5)
[0210] Characteristics of the hyperactive mutant PlyGBS90-1 (SEQ ID NO:5)
were compared to compared to wild-type PlyGBS. The in vitro lytic activity of
PlyGBS90-1 (SEQ ID NO:5) was measured by two different methods. First, we used
various amount of purified PlyGBS90-1 (SEQ ID NO:5) and wild type PlyGBS (2, 10,
50, and 100 ug) in the in vitro assay to measure the Vmax value, as described in
Cheng, Q.et a/., "Removal of group B streptococci colonizing the vagina and
oropharynx of mice with a bacteriophage lytic enzyme,"Antimicrob. Agents
Chemother. 49: 111-117 (2005). We also tested the killing efficacy of mutant
PlyGBS90-1 (SEQ ID NO:5) on GBS in an in vitro viability assay, as described in
Cheng, Q.ef a/., "Removal of group B streptococci colonizing the vagina and
oropharynx of mice with a bacteriophage lytic enzyme,"Antimicrob. Agents
Chemother. 49: 111-117 (2005). The specificity and the optimum pH of the mutant
were analyzed as described in Cheng, Q.et a/., "Removal of group B streptococci
colonizing the vagina and oropharynx of mice with a bacteriophage lytic
enzyme,"Antimicrob. Agents Chemother. 49:111-117 (2005).
[0211] To test the effect of salt concentration on lytic activity, purified
PlyGBS90-1 (SEQ ID NO:5) and PlyGBS were dialyzed against 2 mM Tris-HCI (pH
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7.4) overnight. Various amount of 5M NaCI was added into the dialyzed protein
samples to determine the Vmax values under 0-500 mM salt concentration using a
spectrophotometer, as described in Cheng, Q.ef a/., "Removal of group B
streptococci colonizing the vagina and oropharynx of mice with a bacteriophage lytic
enzyme,"Antimicrob. Agents Chemother. 49:111-117 (2005).
Example 10: In vivo activity of the mutant PlyGBS90-1 (SEQ ID NO:5).
[0212] The mutant PlyGBS90-1 (SEQ ID NO:5) was tested in vivo against
GBS in a mouse vaginal model developed in a previous study (Cheng, Q., D.
Nelson, S. W. Zhu, and V. A. Fischetti, "Removal of group B streptococci colonizing
the vagina and oropharynx of mice with a bacteriophage lytic enzyme," Antimicrob.
Agents Chemother. 49: 111-117 (2005), incorporated herein by reference). Briefly,
on day 1, the estral cycle of 20 six-week-old BALB/c female mice (Charles River Lab,
Wilmington, MA) were synchronized by li-estradiol valerate (McLean, N. W, and I. J.
Rosenstein, "Characterization and selection of a Lactobacillus species to recolonize
the vagina of women with recurrent bacterial vaginosis," J. Med. Microbiol. 49: 543-
552 (2000)). On day 3, the mice were challenged vaginally with 106 colony forming
unit (cfu) StrR NCTC11237 GBS cells. On day 4, the vaginal cavities were swabbed
to determine the colonization status pre-treatment (0 hr samples). The mice were
then randomized into three groups and treated vaginally with either buffer (n=10),
1,500 ug of PlyGBS (n=10), or 1,500 ug of mutant PlyGBS90-1 (SEQ ID NO:5)
(n=10). Mice were then swabbed vaginally 2 hrs and 4 hrs post-treatment. THY
agar plates (Nelson, D., L. Loomis, and V. A. Fischetti, "Prevention and elimination of
upper respiratory colonization of mice by group A streptococci by using a
bacteriophage lytic enzyme," Proc. Natl. Acad. Sci. USA 98: 4107-4112 (2001),
incorporated herein by reference), supplemented with 5% sheep blood and
streptomycin (200 ug / ml), were used to determine the colony counts from wet
swabs. MIXED Model (from SAS Mixed Procedure) was used to compare the
colonization status between groups in statistical analysis and a P value considered significant.
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TABLE 3. BACTERIA STRAINS AND PLASMIDS

BACTERIA Strain Seortype Sourcea
GBS
NCTC11237 IIIR 1
NCTC11237
derivative IIIR, Str* 2
ESCHERICHIA COLI XL-1 Red
BL21(DE3) 3
2
STREPTOCOCCUS ATCC9222 4
SALIVARIUS
BACILLUS CEREUS ATCC4342 2
STAPHYLOCOCCUS AUREUS RN6390 2
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L ASM IDS Phenotype Encoded
protein DESCRIPTION
CQJ67-2 KanR WtPlyGBS Wt plyGBS gene cloned into pET28a ()
CQJ67-2 DERIVATIVE
PCQJ86-6 KanR PlyGBS86-6 A point mutation in plyGBS gene caused D374E
change
PCQJ80 KanR PlyGBS80 A mutant contains the first 163 amino acids of
PlyGBS due to a nonsense mutation.
PCQJ90-1 KanR PlyGBS90-1 A mutation has an out-of-frame deletion in
plyGBS gene (bp 424-1255). It expresses the
first 141 amino acids of PlyGBS plus extra 13
amino acids due to the frameshift.
PCQJ90-8 KanR PlyGBS90-8 A mutant contains the first 138 amino acids of
PlyGBS due to a nonsense mutation.
LYGBS DELETION
UTANTS
PCQJ92 KanR PlyGBS92 738 bp PCR fragment cloned into pET28a by
Ncol/Xhol. The resultant plasmid encodes the
muramidase domain (amino acid 150-394) of the
PlyGBS
PCQJ93 KanR PlyGBS93 885 bp PCR fragment cloned into pET28a by
Ncol/Xhol. The resultant plasmid encodes the
muramidase domain plus C-terminal region
(amino acid 150-443) of PlyGBS.
PCQJ94 KanR PlyGBS94 441 bp PCR fragment cloned into pET28a by
Ncol/Hindlll. pCQJ94 encodes the N-terminal
endopeptidase domain (amino acid 1-146) of the
PlyGBS.
PCQJ95 KanR PlyGBS95 288 bp PCR fragment (C-terminus of plyGBS
gene, bp 1045-1332) cloned into pCQJ94 by
Hindlll/Xhol. The resultant plasmid encodes a
PlyGBS mutant which has a deletion in central
muramidase domain (deletion between amino
acid 147-348).
[0213] While various embodiments of the invention have been described, it
will be apparent to those of ordinary skill in the art that many more embodiments and
implementations are possible within the scope of the invention. Accordingly, the
invention is not to be restricted except in light of the attached claims and their
equivalents.
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CLAIMS
1. A therapeutic composition comprising a bacterial lysin, the bacterial
lysin comprising an isolated amino acid sequence having at least 70%
homology to an amino acid sequence selected from the group
consisting of: SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID
NO:5, SEQ ID NO:8, and SEQ ID NO:9, where the bacterial lysin has a
killing activity against a Group B streptococci bacteria.
2. The therapeutic composition of claim 1, where the killing activity is a
first lytic killing activity against a first Group B streptococci bacteria that
is at least about 1.5-fold greater than a second lytic killing activity of
PlyGBS against the first Group B streptococci bacteria, where the first
lytic killing activity and the second lytic killing activity are measured by
an optical density in vitro lytic killing activity assay;
a. where the optical density in vitro lytic killing activity assay is
performed by measuring a first OD6oo of an assay mixture upon
forming the assay mixture, and measuring a second OD6oo of
the assay mixture 60 minutes after forming the assay mixture,
b. where the assay mixture is formed by mixing 100\iL of a Group
B streptococci bacterial suspension with 100jxL of a bacterial
lysin solution at a temperature of about 25°C;
c. where the bacterial suspension comprises a inoculated bacteria
subcultured and grown to an OD6oo of 0.3, and subsequently
added to a phosphate buffered saline (40mM) at pH of about
5.0;
d. where the bacterial lysin solution comprises a preparation of the
bacterial lysin at 40 lysin activity units/mL in PBS at a pH of
about 5.0; and
-75-

e. where the lysin activity unit is the reciprocal of the highest
dilution of bacterial lysin resulting in a 50% reduction in bacterial
OD6ooin 15min.
3. The therapeutic composition of claim 1, where the bacterial lysin
comprises an isolated amino acid sequence selected from the group
consisting of: SEQ ID NO:2, SEQ ID NO:4, SEQ ID NO:5, SEQ ID
NO:8, and SEQ ID NO:9, where the bacterial lysin has a first lytic killing
activity against a Group B streptococci bacteria that is at least about
25-fold greater than a second lytic killing activity of PlyGBS against the
Group B streptococci bacteria.
4. The therapeutic composition of claim 1, where the bacterial lysin
comprises an isolated amino acid sequence of SEQ ID NO:5, where
the bacterial lysin has a first lytic killing activity against a Group B
streptococci bacteria that is about 40-fold greater than a second lytic
killing activity of PlyGBS against the Group B streptococci bacteria.
5. The therapeutic composition of claim 1, where the incubation of the
bacterial suspension comprising a Group B streptococci bacteria with a
preparation of 3,000 \ig of the bacterial lysin at 40 lysin activity
units/mL in PBS at a pH of about 5.0 for 60 minutes results in at least
about a 400-fold decrease in the Group B streptococci bacteria viability
measured in colony forming units per mL
6. The therapeutic composition of claim 1, where the isolated amino acid
sequence consists essentially of SEQ ID NO:2.
7. The therapeutic composition of claim 1, where the isolated amino acid
sequence consists essentially of SEQ ID NO:3.
8. The therapeutic composition of claim 1, where the isolated amino acid
sequence consists essentially of SEQ ID NO:4.
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9. The therapeutic composition of claim 1, where the isolated amino acid
sequence consists essentially of SEQ ID NO:5.
10.The therapeutic composition of claim 1, where the isolated amino acid
sequence consists essentially of SEQ ID NO:8.
11 .The therapeutic composition of claim 1, where the isolated amino acid
sequence consists essentially of SEQ ID NO:9.
12.The therapeutic composition of claim 1, further comprising a holin
protein.
13. A therapeutic composition comprising a bacterial lysin, the bacterial
lysin comprising an isolated amino acid sequence selected from the
group consisting of: SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ
ID NO:5, SEQ ID NO:8, and SEQ ID NO:9.
14. The therapeutic composition of claim 12, where the bacterial lysin has
a first lytic killing activity against a Group B streptococci bacteria that is
at least about 1.5-fold greater than a second lytic killing activity of
PlyGBS against the Group B streptococci bacteria, where the first lytic
killing activity and the second lytic killing activity are measured by an
optical density in vitro lytic killing activity assay;
a. where the optical density in vitro lytic killing activity assay is
performed by measuring a first ODeoo of an assay mixture upon
forming the assay mixture, and measuring a second OD6oo of
the assay mixture 60 minutes after forming the assay mixture,
b. where the assay mixture is formed by mixing IOOJIL of a Group
B streptococci bacterial suspension with 10OjxL of a bacterial
lysin solution at a temperature of about 25°C;
c. where the bacterial suspension comprises a inoculated bacteria
subcultured and grown to an OD60o of 0.3, and subsequently
-77-

added to a phosphate buffered saline (40mM) at pH of about
5.0;
d. where the bacterial lysin solution comprises a preparation of the
bacterial lysin at 40 lysin activity units/mL in PBS at a pH of
about 5.0; and
e. where the lysin activity unit is the reciprocal of the highest
dilution of bacterial lysin resulting in a 50% reduction in bacterial
OD6ooin 15 min.
15. The therapeutic composition of claim 13, where the bacterial lysin
comprises an isolated amino acid sequence of SEQ ID NO:5, where
the bacterial lysin has a first lytic killing activity against a Group B
streptococci bacteria that is about 40-fold greater than a second lytic
killing activity of PlyGBS against the Group B streptococci bacteria.
16. The therapeutic composition of claim 13, where the bacterial lysin
comprises an isolated amino acid sequence selected from the group
consisting of: SEQ ID NO:2, SEQ ID NO:4, SEQ ID NO:5, SEQ ID
NO:8, and SEQ ID NO:9, where the bacterial lysin has a first lytic killing
activity against a Group B streptococci bacteria that is at least about
25-fold greater than a second lytic killing activity of PlyGBS against the
Group B streptococci bacteria.
17. The therapeutic composition of claim 13, where the incubation of the
bacterial suspension comprising a Group B streptococci bacteria with a
preparation of 3,000 \ig of the bacterial lysin at 40 lysin activity
units/mL in PBS at a pH of about 5.0 for 60 minutes results in at least
about a 400-fold decrease in the Group B streptococci bacteria viability
measured in colony forming units per mL
18. A therapeutic composition comprising a bacterial lysin, the bacterial
lysin comprising an isolated amino acid sequence having at least about
-78-

85% homology to SEQ ID NO:5, where the bacterial lysin has a first
lytic killing activity against a Group B streptococci bacteria that is
greater than a second lytic killing activity of PlyGBS against the Group
B streptococci bacteria, where the first lytic killing activity and the
second lytic killing activity are measured by an optical density in vitro
lytic killing activity assay;
a. where the optical density in vitro lytic killing activity assay is
performed by measuring a first OD600 of an assay mixture upon
forming the assay mixture, and measuring a second OD6oo of
the assay mixture 60 minutes after forming the assay mixture,
b. where the assay mixture is formed by mixing 100u.L of a Group
B streptococci bacterial suspension with 100p.L of a bacterial
lysin solution at a temperature of about 25°C;
c. where the bacterial suspension comprises a inoculated bacteria
subcultured and grown to an OD6oo of 0.3, and subsequently
added to a phosphate buffered saline (40mM) at pH of about
5.0;
d. where the bacterial lysin solution comprises a preparation of the
bacterial lysin at 40 lysin activity units/mL in PBS at a pH of
about 5.0; and
e. where the lysin activity unit is the reciprocal of the highest
dilution of bacterial lysin resulting in a 50% reduction in bacterial
ODeooin 15 min.
19.The therapeutic composition of claim 17, where the bacterial lysin has
a first lytic killing activity against a Group B streptococci bacteria that is
about 40-fold greater than a second lytic killing activity of PlyGBS
against the Group B streptococci bacteria.
-79-

20.The therapeutic composition of claim 17, further comprising a holin
protein.
21 .The therapeutic composition of claim 17, where the lytic enzyme is a
chimeric or shuffled lytic enzyme.
22. A therapeutic composition comprising a bacterial lysin comprising a
PlyGBS peptide variant having a killing activity against a Group B
streptococci bacteria that is greater than the killing activity of the
PlyGBS peptide against the Group B streptococci bacteria.
23.The use of a PlyGBS peptide variant in the manufacture of a
composition for the treratment of a Group B streptococci bacterial
infection, the PlyGBS peptide variant being a PlyGBS mutant having a
killing activity against a Group B streptococci bacteria that is greater
than the killing activity of the PlyGBS peptide against the Group B
streptococci bacteria.
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Methods, compositions and articles of manufacture useful for the treatment of various Group B streptococci (GBS)
bacteria are provided. Various bacterial lysins, including certain PlyGBS mutant lysins, are provided. In particular, PlyGBS mutant
lysins having lytic killing activity against Group B streptococci (GBS) bacteria are provided, including PlyGBS mutant lysins with
greater killing activity against Group B streptococci (GBS) bacteria than the non- mutated PlyGBS bacteria] lysin.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=DK+I4XVWBEapT5ORbxsTBw==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 268518
Indian Patent Application Number 693/KOLNP/2008
PG Journal Number 36/2015
Publication Date 04-Sep-2015
Grant Date 01-Sep-2015
Date of Filing 15-Feb-2008
Name of Patentee THE ROCKEFELLER UNIVERSITY
Applicant Address 1230 YORK AVENUE, BOX 81, NEW YORK, NY
Inventors:
# Inventor's Name Inventor's Address
1 FISCHETTI, VINCENT A 448 JOAN COURT, WEST HEMPSTEAD, NY 11552
2 CHENG, QI 202 CORAL CREEK LANE , MORRISVILLE, NC 27560
PCT International Classification Number C12N 9/78
PCT International Application Number PCT/US2006/032176
PCT International Filing date 2006-08-17
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/710936 2005-08-24 U.S.A.