CA2238610A1 - Fine tuned protegrins - Google Patents

Abstract

The invention is directed to antimicrobial peptides related to naturally-occurring protegrin peptides, and methods of using the peptides in a variety of contexts, including the treatment or prevention of infections.

Description

CA 02238610 1998-0~-22 W O ~7/18826 PCTnUS~6~18~44 FINE TUNED PROTEGRINS

1. CROSS-REFERENCE TO RELATED APPLICATIONS
This invention was made with funding from NIH Grant No.
~ 5 A122839. The U.S. Government has certain rights in this invention.
This application is a continuation-in-part of U.S.
Serial No. 08/960,921 filed August 1, 1996, which is a continuation-in-part of U.S. Serial No. 08/649,811 filed 17 May 1996, which is a continuation-in-part of U.S. Serial No. 08/562,346 filed 22 November 1995, which is a continuation-in-part of U.S. Serial No. 08/499,523 filed 7 July 1995, which is a continuation-in-part of U.S. Serial No. 08/451,832 filed 26 May 1995 which claims priority from PCT/US94/08305 (WO 95/03325) and which is a continuation-in-part of U.S. Serial No. 08/243,879 filed 17 May 1994, which is a continuation-in-part of U.S. Serial No. 08/182,483 filed 13 January 1994, which is a continuation-in-part of U.S.
Serial No. 08/095,769 filed 26 July l9g3, which is a continuation-in-part of U.S. Serial No. 08/093,926 filed 20 July 1993. Benefit is claimed under 35 U.S.C. 120 with respect to U.S. Serial Nos. 08/960,921, 08/649,811 and 08/562,346. The contents of these applications are incorporated herein by reference in their entireties.

2. FIE1D OE THE lNv~NllON
The invention relates to the field of antimicrobial peptides. In particular, the invention concerns short peptides, designated "protegrins," that have a wide range of antimicrobial activities.

3. BACKGROUND OF THE lN v~llON
one of the defense mechanisms against infection by both ~n;~ls and plants is the production of peptides that have ~ 35 antimicrobial and antiviral activity. Various classes of these peptides have been isolated from tissues of both plants ~ and ~n; ~1 fi. PCT application WO 95/03325 (published 2 February 1995) contains a review of the literature on this CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 subject. Such peptides include tachyplesins, which are 17-18 amino acid peptides cont~;ning four invariant cysteines, the defensins, ~-defensins, and insect defensins, which are somewhat longer peptides characterized by six invariant cysteines and antifungal and anti~acterial peptides and proteins which have been found in plants.
The parent applications provide a new class of antimicrobial peptides, designated "protegrins,"
representative members of which have been isolated from porcine leukocytes. The protegrin peptides, which are generally amphiphilic in nature, exhibit broad spectrum antimicrobial activity. Thus, these peptides are useful as antibacterial, anti-fungal and antiviral agents in both plants and ~n; ~
The isolation of some of the protegrin peptides of the invention was reported by the present applicants in a paper by Kokryakov, V.N. et al., 1993, FEBS Lett 337:231-236 (July issue). A later publication of this group described the presence of a new protegrin whose sequence, and that of its precursor, was deduced from its isolated cDNA clone. Zhao, C. et al., 1994, FEBS Lett 346:285-288. An additional paper disclosing cationic peptides from porcine neutrophils was published by Mirgorodskaya, O.A. et al., 1993, FEBS ~ett 330:339-342. Storici, P. et al., 1993, Biochem Bio~hYs Res Comm 196:1363-1367, report the recovery of a DNA sequence which encodes a pig leukocyte antimicrobial peptide with a cathelin-like prosequence. The peptide is reported to be one of the protegrins disclosed hereinbelow. Additional publications related to protegrins are Harwig, S.S.L., et al., 1995, J Pe~tide Sci 3:207; Zhao, C., et al., 1995, FEBS
376:130-134; Zhao, C. et al., 1995, FEBS Lett 368:197-202; Miyakawa, Y. et al., 1996, Infect Immun 64:926-932;
Yasin, B. et al., 1996, Infect Immun 64:709-713; Qu, X-~ et al., 1996, Infect Immun 64:1240-1245; Aumelas, A. et al., 1996, Eur J. Biochem 237:575-583; ~angoni, M.E. et al., 1996, FEBS Lett 383:93-98; Steinberg et al., 1996, "Protegrins:
Fast Acting Bacterial Peptides," presented at 8th Intl.
SYm~OSiUm on Staphylococci and Sta~hylococcal Infections, Aix CA 02238610 1998-0~-22 W O 97/18826 PCTnJS96/I8544 les Bains, France, June 23-26, 1996; Steinberg et al., 1996, "Broad Spectrum Antimicrobial Activity of Protegrin Peptides," presented at 36th Interscience Conference on Antimicrobial Aaents and Chemotherapy, New Orleans, LA, September 15-18, 1996; Kung et al., lg96r "Protegrin Protects Mice From Systemic Infection By Antibiotic-Resistant Pathogens," presented at 36th Interscience Conference on Antimicrobial Aqents and Chemotherapy, New Orleans, LA, September 15-18, 1996; and Steinberg et al., 1996, "In Vitro Efficacy of Protegrins Against ~elicobacter Pylori,"
presented at 36th Interscience Conference on Antimicrobial Aqents and Chemotherapy, New Orleans, LA, September 15-18, 1996.
The protegrins have also been found to bind to endotoxins -- i.e., the lipopolysaccharide (LPS) compositions derived from Gram-negative bacteria which are believed responsible for Gram-negative sepsis. The protegrins are also effective in inhibiting the growth of organisms that are associated with sexually transmitted diseases such as C~lamydia trachomatis and Neisseria gonorr~oeae.
The present invention is directed to a new set of protegrins which offer properties of being rapid acting microbicides having a broad spectrum of activity with a low likelihood of resistance. In addition, the class of protegrins of the present invention offers an additional opportunity to adjust the spectrum of activity with respect to the type of microbe or virus most effectively inhibited and with respect to the conditions under which this inhibition occurs. The protegrins in this case differ from those of the parent applications either by deletion of at least one of the four N-terminal amino acids, or of certain other designated residues and/or by replacement of certain amino acids with those of other classes.

4. SUMMARY OF THE INVENTION
In one aspect, the present invention is directed to antimicrobial peptides contA; n ing about 10-30 amino acid residues characterized by a "core" structure having two main CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18S44 elements: a reverse-turn bracketed by two strands that form an anti-parallel ~-sheet. Generally, the ~-sheet region of the molecule is amphiphilic, one surface being net hydrophobic in character, the other being net hydrophilic in character. The peptides contain at least one basic amino acid residue in the reverse-turn region, and have a net charge of at least +1 at physiological pH. The antimicrobial peptides may optionally be acylated at the N-terminus and/or amidated or esterified at the C-terminus, and may contain zero, one or two disulfide bridges.
In one illustrative embodiment, the invention provides antimicrobial peptides comprising about 10-30 amino acid residues and cont~;n;ng the amino acid sequence:
(I) X1~X2~X3~X4~X5~C6~X7~C8~Xg~xlo~xll~xl2~cl3~xl4~cls~xl5~xl7~xls or a pharamceutically acceptable salt or N-terminal acylated or C-te~ ; n~ amidated or esterified form thereof, wherein:
each of C8 and C13 is independently present or not present, and if present each is independently a cysteine-like, basic, small, polar/large or hydrophobic;
each of C6 and C1s is independently a cysteine-like, basic, small, polar/large or hydrophobic amino acid;
each of X1-X5 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large, or small amino acid;
each of X7 and X14 is independently a hydrophobic or a small amino acid;
each of Xg and X12 is independently present or not present;
Xg-Xl2 taken together are capable of effecting a reverse-turn when contained in the amino acid sequence of formula (I) and at least one of X9-Xl2 must be a basic amino acid;
each of X16-X18 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large or small amino acid;

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 and wherein at least about 15% up to about 50% of the amino acids comprising the antimicrobial peptide are basic amino acids such that the antimicrobial peptide has a net charge of at least +1 at physiological pH.
~ 5 The peptides of the invention exhibit broad spectrum antimicrobial activity, being biocidal against a wide range of microbial targets, including Gram-positive bacteria, Gram-negative bacteria, yeast, fungi and protozoa. Accordingly, the peptides can be used as antimicrobial agents in a wide variety of applications. For example, the peptides can be used to preserve or disinfect a variety of materials, including medical equipment, foodstuffs, cosmetics, contact lens solutions, medicaments or other nutrient-contAining materials. The peptides are also useful for the prophylaxis or treatment of microbial infections or diseases related thereto in both plants and Ani~
In another aspect, the invention is directed to recombinant materials useful for the production of certain of the peptides of the invention as well as plants or animals modified to contain expression systems for the production of these peptides.
In another aspect, the invention is directed to pharmaceutical compositions and to compositions for application to plants contA;ning the peptides of the invention as active ingredients or compositions which contain expression systems for production of the peptides or for }n situ expression of the nucleotide sequence encoding these peptides.
In still another aspect, the invention is directed to methods of preparing the invention peptides synthetically, to antibodies specific for these peptides, and to the use of the peptides as preservatives.
In yet another aspect, the present invention is directed to methods of using the above-described peptides, or~ 35 compositions thereof, to inhibit microbial growth. The method generally involves contacting a microbe with an antimicrobially effective amount of one or more of the peptides or compositions of the invention. In a preferred CA 02238610 1998-0~-22 W O 97/18826 PCTrUS96/18544 embodiment, a bacteria is contacted with a bactericidally effective amount of peptide or composition.
In a final aspect, the present invention is directed to methods of using the above-described peptides, or compositions thereof, to prevent or treat micro~ial in~ections or diseases related thereto in both plants and animals. The method generally involves Al' ; n; stering to a plant or ~n;~l an effective amount of one or more of the peptides or compositions of the invention. Such diseases or infections include eye infections such as con~unctivitis and keratitis, corneal ulcers, stomach ulcers associated with H.
pylori, sexually transmitted diseases (STDs~, and Gram-negative sepsis. Clinically relevant infections that can be treated or prevented ~y the peptides of the invention include systemic infections caused by multi-drug resistant pathogens such as vancomycin-resistant Enterococcus faecium, methicillin-resi~tant Staphylococcus aureus and penicillin-resistant Streptococcus pneumoniae.

5. BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows the nucleotide se~uence and the deduced amino acid sequence of the genomic DNA encoding the precursor protein ~or the antimicrobiai compounds PG-1, PG3, and PG-5.
Figure 2 shows the organization of the protegrin genomic DNA.
Figures 3a-3c show the antimicrobial activity of synthetically prepared PG-5 as compared to that of synthetically prepared PG-1.
Figure 4 is a graphical representation of the effect of serial transfer into antibiotic-cont~;n;ng media on the development of drug resistance in methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa.
Figure 5 is an illustration of the sequences of protegrins PG-1 through PG-5; and Figure 6 is an illustration of a ~-sheet secondary peptide structure.

CA 02238610 1998-0~-22 W O 97/188Z6 PCT~US96/18544

6. ~ETAILED DESCRIPTION OF ~HE lNv~N~ oN
6.1 Definitions As used herein, the following terms shall have the following e?n; n~s:
"SecondarY Structure:" As used herein, "secondary structure" refers to the regular local structure of segments of polypeptide ~h~in~ including, but not limited to, helices such as a-helices, extended strands such as ~-strands and sheets of e~tended strands such as ~-sheets.
lo "Anti-Parallel ~-Sheet:" As used herein "anti-parallel ~-sheet" refers to a secondary structure of a polypeptide chain characterized by intermolecular backbone-backbone hydrogen hon~; ng between anti-parallel peptide strands. An anti-parallel ~-sheet may optionally contain one or two interstrand disulfide linkages.
"Amphiphilic Anti-Parallel ~-Sheet:" As used herein, "amphiphilic anti-parallel ~-sheet" refers to an anti-parallel ~-sheet wherein one surface has a net hydrophobic character and another surface has a net hydrophilic character.
"Reverse-Turn:" As used herein, "reverse-turn"
refers to a characteristic secondary structure that links adjacent strands of an anti-parallel ~-sheet. Typically, a "reverse-turn" is a two to four amino acid residue peptide segment that reverses the direction of a polypeptide chain so as to allow a single polypeptide chain to adopt an anti-parallel ~-sheet conformation. Such peptide segments are well known in the art and include, by way of example and not limitation, three amino acid residue ~-turns (Rose et al., 1985, Adv. Protein Chem. 37:1-109; Wilmer-White et al ., 1987, Trends Biochem. Sci. 12:189-192; Wilmot et al., 1988, J. Mol.
Biol. 203:221-232; S;hAn~A et al ., 1989, J. Mol. Biol.
206:759-777; Tramontano et al., 1989, Proteins: Struct.
Funct. Genet. 6:382-394) and four amino acid residue ~-turns, as described below.
"~-Turn:" As used herein, "~-turn" refers to a recognized sub-class of reverse-turns. Typically, a "~-turn"
is a four amino acid residue peptide segment that reverses CA 02238610 1998-0~-22 W O 97/18826 PCTAUS96/lgS44 the direction of a polypeptide chain so as to allow a single polypeptide chain to adopt an anti-parallel ~-sheet secondary structure. Generally, the two internal amino acid residues of the ~-turn are not involved in the hydrogen-bonding of the ~-sheet; the two amino acid residues on either side of the internal residues are included in the hydrogen-bonding of the ~-sheet. The term "~-turn~' expressly includes all types of peptide ~-turns commonly known in the art including, but not limited to, type-I, type-II, type-III, type-I', type-~I' and type-III' ~-turns (see, Rose et al ., 1g85, Adv. Protein Chem.
37:1-109; Wilmer-White et al., 1987, Trends Biochem. Sci.
12:189-192; Wilmot et al ., 1988, J. Mol. Biol. 203:221-232;
S;h~n~ et al., 1989, J. Mol. Biol. 206:759-777; Tramontano et al., 1989, Proteins: Struct. Funct. Genet. 6:382-394).
"AntimicrobiallY Effective Amount:" As used herein, "antimicrobially effective amount" refers to an amount of peptide (or composition thereof) that is biostatic or biocidal against a target microbe. More specifically, an antimicrobially effective amount of peptide refers to an amount of peptide that inhibits the growth of, or is lethal to, a target microbe.
"TheraPeuticallY Ef~ective Amount" As used herein, "therapeutically effective amount" refers to an amount of peptide (or composition thereof) effective to ameliorate the symptoms of, or ameliorate, treat or prevent microbial infections or diseases related thereto in both plants and animals.
"PharmaceuticallY AccePtable Salt:" As used herein, "pharmaceutically acceptable salt" refers to those salts which substantially retain the antimicrobial activity of the free bases and which are obtained by reaction with inorganic acids.

6.2 DescriPtion of the Preferred Embodiments The present invention provides protegrin peptides having antimicrobial activity, compositions comprising the peptides, methods of using the peptides (or compositions thereof) to inhibit the growth of or kill a wide variety of wo 97/18826 PCT~US96/18544 microbial targets and methods of using the peptides (or compositions thereo~) to treat or prevent micro~ial infections and diseases related thereto in both plants and n t 5~
The peptides of the invention exhibit broad spectrum antimicrobial activity, being biostatic or biocidal against a , wide range of microbial targets, including but not limited to, Gram-positive bacteria such as L. monocytogenes, B.
subtilis, E. faecalis ( including vancomycin-sensitive (VSEF) and vancomycin-resistant (VREF) strains), E. faecium (including vancomycin-sensitive (VSEF) and vancomycin-resistant (VREF) strains), S. aureus (including methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) strains), S. epidermis ( including methicillin-sensitive (MSSE) and methicillin-resistant (MRSE) strains), S. salivarius, C.
minutissium, C. pseudodiptheriae, C. stratium, Corynebacterium group G1, Coryne~acterium group G2, S.
rne ~niae (including penicillin-resistant (PSRP) strains), S. mitis and S. sanguis; Gram-negative bacteria including A.
calcoaceticus, E. coli, R. pneumoniae, P. aeruginosa, S.
marcescens, H. influenza, Moraxella sp., N. meningitidis, S.
typhimurium, H. pylori, H. felis, and C. jejuni; as well as protozoa, yeast and certain strains of viruses and retroviruses. Significantly, the peptides described herein are biostatic or biocidal against clinically relevant pathogens exhibiting multi-drug resistance such as, among others, v~nc~ ycin-resistant Enterococcus faecium or faecalis ("VR~"), penicillin-resistant Streptococcus pne7~moniae ("PRSP") and methicillin-resistant Staphylococcus aureus ("MRSA").
The peptides of the invention (or compositions thereof) are useful as biocidal or biostatic agents in a wide variety of applications. For example, the peptides can be used to disinfect or preserve a variety of materials including 3~ medical instruments, foodstuffs, medicaments, contact lens solutions, cosmetics and other nutrient-cont~; n i ng materials.
The peptides of the invention are particularly useful as bacteriostatic or bactericidal agents against multi-drug-CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 resistant pathogens such as VRE, MRSA and MSSE in a variety of clinical settings.
The peptides of the invention, or compositions thereof, are also useful for the prophylaxis or treatment of microbial infections and diseases related thereto in both plants and animals. Such dis~ include, but are not limited to, Gram-negative and Gram-positive bacterial infections, endocarditis, pneumonia and other respiratory infections, urinary tract infections, systemic candidiasis, oral mucositis, etc.
The peptides described herein provide significant advantages over traditional antibiotics and/or other antimicrobial peptides. For example, as the peptides described herein are related to antimicrobial peptides found naturally ~n i ~1 S, it is believed that the relatively high frequency of resistance observed for traditional antibiotics will not be observed for the peptides described herein.
A particular advantage of some of the protegrins of the invention, especially the "mini-protegrin~' form having fewer than eighteen amino acids, lies in their reduced size. As a consequence, they are less costly to produce, generally are expected to provide better distribution in tissue and are less immunogenic.

6.2.1 The PePtides Generally, the protegrin peptides of the invention include the amino acid sequence:
(I) X1_X2_X3_X4_XS-C6-X7-CB-X9-X10-X11-X1Z-C13-X1~-C15-X16 X17 X18 and its defined modified forms. Those peptides which may coincidentally occur in nature must be in a purified and/or isolated form or prepared synthetically or recombinantly.
The designation X~ in each case represents an amino acid at the specified position in the peptide. Similarly, the designation Cn represents an amino acid at the specified position and further represents those positions in the amino I

CA 022386l0 l998-05-22 WO 97/18826 PCTrUS96/18544 acid sequence of formula (I) which may optiona~ly contain amino acid residues capable of forming disulfide interlinkages.
The amino acid residues denoted by Xn or Cn may be the genetically encoded L-amino acids, naturally occurring non-genetically encoded L-amino acids, synthetic L-amino acids or D-enantiomers of all of the above. The amino acid notations used herein for the twenty genetically encoded L-amino acids and common non-encoded amino acids are conventional and are as follows:
Common Amino Acid Abbreviations One-Letter Common Amino Acid Symbol Abbreviation AlAnine A Ala ~rginine R Arg A~parag$ne N A~n A~partic acid D A~p Cy~teine C Cy~
Glutamine Q Gln Glutamic acLd E Glu .Glycine G Gly Hi~tidine H Hi~
I~oleucine I Ile Leucine L Leu Ly~ine K Ly~
Meth;o~i no M Met Phenyl~l~ninO F Phe Proline P Pro Serine S Ser Threonine T Thr Tryptophan W Trp Tyrosine Y Tyr Valine V Val ornithine O Orn ~ - ~1 Ani no bAla 2 r 3-rl; ~i n~propionic Dpr acLd a-aminoiRobutyric acid Aib N-methylglycine MeGly (Rarcosine) Citrulline Cit t-butyl~l ~ni no t-BuA
t-butylglycine t-BuG
N-methyli~oleucine MeIle phenylglycine Phg cyclohexylRl~n;n~ Cha W O 97/188~6 PCT~US96/18544 O~e-Lottcr Common Amino Acid Symbol Abbreviation Norleucine Nle 1-naphthyl~l An i n~ 1-Nal 2-naphthy7~1 ~n i n~ 2-NaL
4-chlorophenyla 1 ~ n ~ n~ Phe(4-Cl) 2-fluorophenylRl~nin~ Phe(2-F) 3-fluo~ophenyl~l ~ni n~ Phe(3-F) 4-fluorophenylF~lAnin~ phe(4-F) Penicilll i n~ P~n 1,2,3,4-tetrahydro- Tlc i~oquinoline-3-carboxylic acid ~-2-thienyla~ n ~ n e Thi Me~hi n~i n~ sulfoxid~ MSO
Homoarginine Har N-acetyl ly~ine AcLys 2r4-~i~m; no butyric acid Dbu p-aminophenyl~l~ n i n~ Phe(pNH2) N-methylvaline ~eVal Homocysteine hCys Homoserine hSer ~-amino hexanoic acid Aha ~-amino valeric acid Ava 2,3-~innbutyric acid Dab ~yd.O~y~ oline Hyp Parabenzylphenyl~l ~ n; n~ Pba Homopheny~l A n ~ n~ hPhe N-methylphenyl~ 1 ~n ~ nF~ MePhe The compounds of the invention are peptides which are partially defined in terms of amino acid residues of designated classes. Amino acid residues can be generally subclassified into major subclasses as follows:
~ cidic: The residue has a negative charge due to loss of H~ ion at physiological pH and the residue is attracted by a~ueous solution so as to seek the surface positions in the conformation of a peptide in which it is contained when the peptide is in aqueous medium at physiological pH.
B~sic: The residue has a positive charge due to association with H~ ion at physiological pH and the residue is attracted by a~ueous solution so as to seek the surface positions in the conformation of a peptide in which it is contained when the peptide is in aqueous medium at physiological pH.

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 H~dro~hobic: The residues are not charged at physiological pH and the residue is repelled by aqueous solution so as to seek the inner positions in the conformation of a peptide in which it is contained when the peptide is in aqueous medium.
Polar/lar~e: The residues are not charged at physiological pH, but the residue is not sufficiently repelled by aqueous solutions so that it would necessarily seek an inner position in the conformation of the peptide in which it is contained when the peptide is in aqueous medium.
Depending on the conditions, and on the remaining amino acids in the sequence, the residue may reside either in the inner space or at the surface of the protein.
CYsteine-Like: Residues having a side chain capable of participating in a disulfide linkage. Thus, cysteine-like amino acids generally have a side chain containing at least one thiol (SH) group, such as cysteine, homocysteine, penicillamine, etc., with cysteine being preferred.
Small: Certain neutral amino acids having side ch;~
that are not sufficiently large, even if polar groups are lacking, to confer hydrophobicity. "Small" amino acids are those with four carbons or less when at least one polar group is on the side chain and three carbons or less when not.
The gene-encoded secondary amino acid proline (as well as proline-like imino acids such as 3-hydroxy proline and 4-hydroxy proline~ is a special case due to its known effects on the secondary conformation of peptide ch~;n~, and is not, therefore, included in a group.
It is understood, of course, that in a statistical collection of individual residue molecules some molecules will be charged, and some not, and there will be an attraction for or repulsion from an aqueous medium to a greater or lesser extent. To fit the definition of 'Icharged~'' a significant percentage (at least approximately 25%) of the individual molecules are charged at physiological pH. The degree of attraction or repulsion required for classification as polar or nonpolar is arbitrary and, therefore, amino acids specifically contemplated by the CA 02238610 1998-0~-22 invention have been classified as one or the other. Most amino acids not specifically named can be classified on the basis of known behavior.
Amino acid residues can be further subclassified as cyclic or noncyclic, and aromatic or nonaromatic, self-explanatory classifications with respect to the side-chain substituent yLOU~S of the residues.
Certain commonly encountered amino acids which are not genetically encoded of which the peptides of the invention may be composed include, but are not limited to, ~-alanine (b-Ala) and other omega-amino acids such as 3-aminopropionic acid, 2,3~ ~;nopropionic acid (Dpr), 4-aminobutyric acid and so forth; ~-aminoisobutyric acid (Aib); ~-aminohexanoic acid (Aha); ~-aminovaleric acid (Ava); N-methylglycine or sarcosine (MeGly); ornithine (Orn); citrulline (Cit);
t-butyl A l~n;ne (t-BuA); t-butylglycine (t-BuG);
N-methylisoleucine (MeIle); phenylglycine (Phg);
cyclohexyl~lAnine (Cha); norleucine (Nle); l-naphthylalanine (1-Nal); 2-naphthylalanine (2-Nal); 4-chlorophenylalanine (Phe(4-Cl)); 2-fluorophenyl~l~n;ne (Phe(2-F)); 3-fluorophenylalanine (Phe(3-F)); 4-fluorophenylalanine (Phe(4-F)); penicillamine (Pen); 1,2,3,4-tetrahydroiso~uinoline-3-carboxylic acid (Tic); ~-2-thienylalanine (Thi); methionine sulfoxide (MSO); homoar~inine (Har); N-acetyl lysine (AcLys);
2,3-di~rinohutyric acid (Dab); 2~4-di~r;nohutyric acid (Dbu);
p-aminophenylalanine (Phe(pNH2)); N-methyl valine (MeVal);
homocysteine (hCys); hydroxyproline (Hyp);
Parabenzylphenylalanine (Pba); HomophenylAl~nine (hPhe); N-methylphenyl~l~n;~e (MePhe); and homoserine (hSer). These amino acids also fall conveniently into the categories defined above.
The classifications of the above-described genetically encoded and non-encoded amino acids are summarized in Table 1, below. It is to be understood that Table 1 is for illustrative purposes only and does not purport to be an exhaustive list of amino acid residues that may comprise the peptides described herein.

CA 022386l0 l998-05-22 WO 97/18826 PCT~US96~18S44 Table 1 Amino A¢id Classifications Cla~ification Genetically Fnco~ Non-Genetically P~.n ~~o~
Hydrophobic Y, V, I, L, M, F, W Phg, 1-Nal, 2-Nal, ThL, Tic, Phe(4-Cl), Phe(2-F), Phe(3-F), Phe(4-F), t-BuA, t-8uG, ~eIle, Nle, MeVal, Cha, hPhe, MePhe, Pba Acidic D, E
BaRic H, K, R Dpr, Orn, hArg, phe( NH2), Dbu, Da~
PO1artLarge Q, N CLt, AcLy~, MSO
Small G, S, A, ~ bAla, MeGly, ALb, hSer CyRteine-Like C Pen, hCy~
In the peptides of formula I, the symbol "-" between amino acid residues Xn and/or Cn generally designates a backbone interlinkage. Thus, the symbol "-" usually designates an amide linkage (-C(O)-NH). It is to be understood, however, that in all of the peptides of the invention one or more amide linkages may optionally be replaced with a linkage other than amide. Such linkages include, but are not limited to, -CH2NH-, -CH2S-, -CH2CH2, -CH=CH- (cis and trans), -C(O)CH2-, -CH(OH)CH2- and -CH2SO-.
Peptides having such linkages and methods for preparing such peptides are well-known in the art (see, e.g., Spatola, 1983, Veqa Data ~3) (general review); Spatola, 1983, "Peptide Backbone Modifications" In: ChemistrY and BiochemistrY of Amino Acids Pe~tides and Proteins (Weinstein, ed.), Marcel Dekker, New York, p. 267 (general review);
Morley, 1980, Trends Pharm. Sci. 1:463-468; Hudson et al., 1979, Int. J. Prot. Res. 14:177-185 (-CH2NH-, -CH2CH2-);
Spatola et al., 1986, Life Sci. 38:1243-1249 (-CH2-S); Hann, 1982, J. Chem. Soc. Perkin Trans. I. 1:307-314 (-CH=CH-, cis and trans); Almquist et al., 1980, J. Med. Chem. 23:1392-1398 (-COCH2-); Jennings-White et al ., Tetrahedron. Lett. 23:2533 (-COCH2-); European Patent Application EP 45665 (1982) CA:97:39405 (-CH(OH)CH2-); Holladay et al ., 1983, Tetrahedron CA 02238610 1998-0~-22 W O 97/18826 PCTrUS96/18544 ~ett. 24:4401-4404 (-C~OH)CH2-); and Hruby, 1982, Life Sci.
31:189-199 (-CH2-S-).
Generally, the peptides of the invention are comprised of about 10 to 30 amino acid residues. Thus, it is to be understood that while formula (I) designates eighteen specified amino acid positions comprising the "core" peptide structure, the peptides of the invention may contain fewer than or greater than 18 amino acids without deleteriously affecting, and in some cases even enhancing, the antimicrobial or other useful properties of the peptides.
For peptides containing fewer than 18 amino acid residues, certain specified amino acids are not present within the peptide sequence, as will be discussed in more detail below.
For peptides containing greater than 18 amino acid residues, the amino acid sequence shown as formula (I) may contain extensions at the N- and/or C-terminus of additional amino acid residues or peptide sequence. It is to ~e understood that such additional amino acid residues or peptide sequences are non-interfering in that they will not significantly deleteriously affect the antimicrobial activity of the peptide as compared with naturally occurring protegrins.
The peptides of the invention are characterized by a "core" structure containing two main elements or motifs: a reverse-turn region bracketed by two strands that form an anti-parallel ~-sheet. While not intending to be bound by theory, it is believed that the antimicrobial activity of the compounds of formula (I) is in part associated with such a core structure.
The ~-sheet region of the peptides comprises an N-strand (residues Xl-C~) and a C-strand (residues C13-Xl8). The N-strand and C-strand are arranged anti-parallel to one another and are non-covalently linked together via backbone-backbone hydrogen bonds (for a detailed description of the structure of ~-sheets the reader is referred to Creighton, 1993, Protein Structures and Molecular ProPerties, W.H. Freeman and Co., NY, and references cited therein). While not intending to be bound by theory, it is believed that the most important CA 02238610 1998-0~-22 W ~ 97/18826 PCTAUS96/18544 residues comprising the ~-sheet region are residues X5-C8 and Cl3--Xl6 -Preferably, the ~-sheet region of the peptides is amphiphilic, i.e., one surface of the ~-sheet has a net hydrophobic character and the other surface has a net hydrophilic character. ~eferring to the ~-sheet structure illustrated in Figure 6, the side chA;n~ of L-amino acid residues adjacent to one another intrastrand-wise (residues n, n~1, n+2, etc.) point in opposite directions so as to be positioned on opposite surfaces of the ~-sheet. The side r.h~;n~ of L-amino acid residues adjacent to one another interstrand-wise (residues n and c, n~l and c+1, etc.) point in the same direction so as to be positioned on the same surface of the ~-sheet. Using this general structural motif an amphiphilic antiparallel ~-sheet is obtained by selecting amino acids at each residue position so as to yield a ~-sheet having hydrophobic side ~~.h;~;n~: positioned on one surface of the sheet and hydrophilic side chains positioned on the other.
Of course, it will be appreciated that as the surfaces of the amphiphilic anti-parallel ~-sheet region need only have net hydrophobic or net hydrophilic character, each side chain comprising a particular surface need not be hydrophobic or hydrophilic. The surfaces may contain side c-h~;n!: that do not significantly alter the net character of the surface.
For example, both the hydrophobic and hydrophilic surfaces may contain small amino acid side chains, as these side c-h~in~: do not significantly contribute to the net character of the surface.
The ~-sheet region of the peptides of formula I may contain from one to four cysteine-like amino acids, designated C~, C8, C13 and Cl5, which may participate in interstrand disulfide bonds. The peptides of the invention that contain at least two cysteine-like amino acid residues may be in straight-chain or cyclic form, depending on the extent of disulfide bond formation. The cyclic forms are the t result of the formation of disulfide lin~ages among all or some of the four invariant cysteine-like amino acids. Cyclic CA 02238610 1998-0~-22 W O 97/188Z6 PCT~US96tl8544 forms of the invention include all possible permutations of disulfide bond formation. The straight-chain forms are convertible to the cyclic forms, and vice versa. Methods for forming disulfide bonds to create the cyclic forms are well known in the art, as are methods to reduce disulfides to form the linear compounds.
The naturally occurring protegrins (P&-1 through PG-5) contain two disulfide bonds; one between cysteines C6-Cls and another between cysteines C8-C13 (Harwig et al., 1995, J.
PePtide Sci. 3:207). Accordingly, in those embodiments having two disulfide linkages, the C6-Cls, C8-C13 form is preferred. Such peptides are designated "native" forms.
However, it has been found that forms of the protegrins containing only one disulfide linkage are active and easily prepared. Preferred among embodiments having only one disulfide linkage are those represented by C6-Cls alone and by C~-C13 alone.
Forms cont~in;ng a C6-C15 disulfide as the only disulfide linkage are generally designated "bullet" forms of the protegrins; those wherein the sole disulfide is C8-C13 are designated the "kite" forms. The bullet and kite forms can most conveniently be made by replacing each of the cysteine-like amino acid residues at the positions that are not involved in a disulfide linkage with amino acids that do not participate in disulfide bonds, preferably with small amino acids such as glycine, serine, AlAn;ne or threonine.
Alternatively, Ca and/or C13 may be absent.
As the linearized or "snake" forms of the native peptides have valuable activities, the peptides of the invention include linearized forms wherein the sulfhydryl (SH) groups are chemically stabilized with suitable reagents.
As defined herein, "SH-stabilized" forms of the peptides of the invention contain sulfhydryl groups that have been reacted with stAn~rd reagents to prevent reformation of 3~ disulfide linkages or forms wherein the cysteine-like amino acid residues are replaced by other amino acids as set forth above. It is preferred that all four cysteine-like amino acid residues be replaced or SH-stabilized in order to CA 02238610 1998-0~-22 in;~; ze the likelihood of the formation of intermolecular disulfide linkages.
The sulfur atoms involved in an interstrand disulfide bridge in a ~-sheet are not positioned within the plane~ 5 defined by the interstrand backbone-backbone hydrogen-bonds;
the sulfur atoms are at an angle with respect to the ~-carbons of the bridged amino acid residues so as to be positioned on a surface of the ~-sheet. Thus, the sulfur atoms of the disulfide linkages contribute to the net hydrophilicity of a surface of the ~-sheet. It is to be understood that in the peptides of formula I a ~-sheet region defined by the following formula is specifically contemplated to fall within the definition of amphiphilic antiparallel sheet as described herein:
ll 6 -X7 -11 8 Cl5--Xl4--Cl3 wherein C6, C8, C13 and C15 are each independently a cysteine-like amino acid, X7 and Xl4 are each independently a hydrophobic or small amino acid and ¦¦ is a disulfide bond.
In a particularly preferred embodiment, C6, C8, C13 and C1s are each cysteine and X7 and X14 are each independently hydrophobic amino acids.
The ~-sheet secon~y structure illustrated in Figure 6 is composed entirely of L-amino acids. Those having skill in the art will recognize that substituting an L-amino acid with its corresponding D-enantiomer at a specific residue position may disrupt the structural stability or amphiphilicity of amphiphilic anti-parallel ~-sheet region. The degree to which any particular enantiomeric substitution disrupts the structural stability or amphiphilicity depends, in part, on the size of the amino acid side chain and position of the residue within the ~-sheet. Preferably, the ~-sheet region of the peptides of formula I will contain mixtures of L- and D-amino acids that do not significantly affect the stability or amphiphilicity of the ~-sheet region as compared to peptides cont~;ning the corresponding all D- or all L-enantiomeric forms of the sheet. Enantiomeric substitutions that do not substantially affect the stability CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 or amphiphilicity of the ~-sheet region will be readily apparent to those having skill in the art.
In a preferred embodiment of the invention, hydrophobic, basic, polar/large and cysteine-like amino acids comprising the ~-sheet region are either all L-enantiomers or all D-enantiomers. Small amino acids comprising the ~-sheet region may be either L-enantiomers or D-enantiomers.
The reverse-turn region of the peptides of formula I
(residues Xg-XlO-Xll-Xl2 taken together) links the strands of the anti-parallel ~-sheet. Thus, the reverse-turn region comprises a structure that reverses the direction of the polypeptide chain so as to allow a reglon of the peptide to adopt an anti-parallel ~-sheet secondary structure.
The reverse-turn region of the molecule generally comprises two, three or four amino acid residues (residue Xg and/or X12 may be absent). An important feature of the peptides of the invention is the presence of a positive charge in the turn region of the molecule. Thus, one of Xg-X12, and preferably two of Xg-Xl2, must be a basic amino acid.
Such two, three and four amino acid segments capable of effecting a turn in a peptide are well known and will be apparent to those of skill in the art.
In a preferred embodiment of the invention, the reverse-turn is a three amino acid residue ~-turn. Virtually any ~-turn se~uence known in the art may be used in the peptides of the invention, including those described, for example, in Rose et al., 1985, Adv. Protein Chem. 37:1-109; Wilmer-White e~ al., 1987, Trends Biochem. Sci. 12:189-192; Wilmot et al ., 1988, J. Mol. Biol. 203:221-232; S;h~n~ et al ., 1989, J.
~ol. Biol 206:759-777; and Tramontano et al., 1989, Proteins:
~truct. Funct. Genet. 6:382-394.
In another preferred embodiment the reverse-turn is a four amino acid residue ~-turn. In such structures, the two internal amino acid residues of the turn are usually not involved in the hydrogen-bonding of the anti-~arallel ~-sheet; the two amino acid residues on either side of the internal residues are usually included in the hydrogen-bonding of the ~-sheet. While not intending to be bound by CA 022386l0 l998-05-22 WO 97/18826 PCT~US96/1854 theory, it is believed that such hydrogen bonding helps stabilize the ~-sheet region o~ the molecule.
The conformations and sequences o~ many peptide ~-turns have been well-described in the art and include, by way of~ ~ example and not limitation, type-I, type-I', type-II, type-II', type-III, type-III', type-IV, type-V, type-V', type-VIa, type-VIb, type-VII and type-VIII (see, Richardson, 1981, Adv. Protein Chem. 34:167-339; Rose et al., 198~, Adv.
Protein Chem. 37:1-109; Wilmot et al ., 1988, J. Mol. Biol.
203:221-232; S; h~n~ et al ., 1989, J. Mol. Biol. 206:759-777;
Tramontano et al., 1989, Proteins: struct. Funct. Genet.
6:382-394). All of these types of peptide ~-turn structures and their corresponding sequences, as well as later discovered peptide ~-turn structures and sequences, are specifically contemplated by the invention.
The specific conformations of short peptide turns such as ~-turns depend primarily on the positions o~ certain amino acid residues in the turn (usually Gly, Asn or Pro).
Generally, the type-I ~-turn is compatible with any amino acid residue at positions Xg through Xl2, except that Pro cannot occur at position X11. Gly predominates at position Xl2 and Pro pr~ ;n~tes at position XlO of both type-I and type-II turns. Asp, Asn, Ser and Cys residues frequently occur at position Xg, where their side ch~; n~ often hydrogen-bond to the NH of residue Xll.
In type-II turns, Gly and Asn occur most frequently at position Xll, as they adopt the required backbone angles most easily. Ideally, type-I~ turns have Gly at positions XlO and X1l, and type-II' turns have Gly at position XlO. Type-III
turns generally can have most amino acid residues, but type-III' turns usually re~uire Gly at positions XlO and Xl~.
Type-VIa and VI~ turns generally have a cis peptide bond and Pro as an internal residue. For a review of the different types and se~uences of ~-turns in proteins and 3~ peptides the reader is referred to Wilmot et al.~ 1988, J.
Mol. Biol. 203:221-232.
Preferred ~-turn se~uences are as follows (listed in order Xg to Xl2): ZZZG; ZZZF; ZZSG; ZZAL; ZGZL; ZFZL; ZPZV;

CA 02238610 1998-0~-22 ZPZF; ZGZY; IZGZ; LZZF; YZGZ, wherein each Z is independently an L- or D-enantiomer of R, K, Dbu or Orn.
Additional preferred ~-turns include those wherein XlO
and/or Xl1 are Tic or Hyp, as these residues are known to effect or induce ~-turn structures in peptides and proteins.
The peptides of the invention are generally basic, i.e., they have a net positive charge at physiological pH. While not int~n~;ng to be bound by theory, it is believed that the presence of positively charged amino acid residues, particularly in the turn region of the molecule, is important for antimicrobial activity.
It is understood that in a statistical collection of individual amino acid residues in a structure such as a peptide some of the amino acid residues will be positively charged, some negatively charged and some uncharged. Thus, some of the peptides will have a charge and some not. To fit the definition of "basic," an excess of amino acid residues in the peptide molecule are positively charged at physiological pH. Thus, approximately 15% but no more than up to about 50% of the amino acids must be basic amino acids, and the compounds must have a net charge of at least +1 at physiological p~. Preferably, the peptides of the invention will have a net charge of at least +3 at physiological pH.
For embodiments having as few as 10 amino acids, there may be only one basic amino acid residue; however, at least two basic residues, even in this short-chain residue, are preferred. If the protegrin peptide contains as many as 15 amino acid residues, two basic residues are required. It is preferred that at least 20~ of the amino acids in the sequence be basic, with 30% basic amino acids being particularly preferred.
The amino terminus of the peptides of the invention may be in the free amino form or may be acylated by a group of the formula RCO-, wherein R represents a hydrocarbyl group of 1-25C, preferably 1-lOC, more preferably 1-8C. The hydrocarbyl group can be saturated or unsaturated, straight chain, branched or cyclic, and is typically, for example, methyl, ethyl, isopropyl, t-butyl, n-pentyl, cyclohexyl, CA 02238610 1998-0~-22 WO 97/18826 PCT~S96/18544 cyclohexene-2-yl, hexene-3-yl, hexyne-4-yl, octyl, decyl, eicanosyl and the like, with octyl being preferred.
Alternatively, the N-terminus may contain aromatic groups such as naphthalene, etc. Such groups may be~ 5 conveniently incorporated into the peptides of the invention by using amino acids such as 1-naphthylalanine or 2-naphthylalanine as the N-terminal amino acid residue.

The N-terminus of the peptides may also be substituted to use solute-specific transmembrane channels to facilitate their entry into the bacterial periplasm. For example, the N-terminus may be conveniently modified with catechol using catechol-NHS activated ester.
The C-terminus of the peptides of the invention may be in the form of the underivatized carboxyl group, either as the free acid or an accepta~le salt, such as the potassium, sodium, calcium, magnesium, or other salt of an inorganic ion or of an organic ion such as caffeine. In some embodiments, it is difficult to make salts since the r- - in~er of the molecule bears a positive charge which may repel the relevant cation. The carboxyl terminus may also be derivatized by formation of an ester with an alcohol of the formula ~OH, or may be amidated by an amine of the formula NH3, or RNH2, or R2NH, wherein each R is independently hydrocarbyl of 1-25C as defined and with preferred embodiments as above. Amidated forms of the peptides wherein the C-terminus has the formula CONH2 are preferred.
Addition of lipophilic groups at the C- and/or N-terminus facilitates the transition of the peptide into the membrane of the target microbe and penetration into sites of infection. Choice of optimum substitution is determined by evaluation with respect to the lipid content of the target microbe.
Thus, in one illustrative embodiment, the invention 3~ provides antimicrobial peptides comprised of about 10-30 amino acid residues and cont~; n i~g the amino acid sequence:
.r (I) X1-X2-X3-X4-X5-C6-X,-C8-Xg-Xl0-xll-xl2-cl3-xl4-cl~-xl6-xl7-xl8 CA 02238610 1998-0~-22 W O 97/18826 PCTnJS96/18544 or a pharamceutically acceptable salt or N-terminal acylated or C-terminal amidated or esterified form thereof, wherein:
each of C8 and Cl3 is independently present or not present, and if present each is independently a ~ysteine-like, basic, small, polar/large or hydrophobic;
each of C6 and Cl5 is independently a cysteine-like, basic, small, polar/large or hydrophobic amino acid;
each of Xl-X5 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large, or small amino acid;
each of X7 and Xl4 is independently a hydrophobic or a small amino acid;
each of X9 and Xl2 is independently present or not present;
Xg-Xl2 taken together are capable of effecting a reverse turn when contained in the amino acid sequence of formula (I) and at least one of Xg-Xl2 must be a basic amino acid;
each of Xl6-Xl8 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large or small amino acid;
and wherein at least about 15% up to about 50% of the amino acids comprising said antimicrobial peptide are basic amino acids such that said antimicrobial peptide has a net charge of at least ~1 at physiological pH.

In one class of protegrins described herein, either the hydrophobic amino acids found in the naturally occurring protegrins at X5 are replaced with a basic amino acid and/or at least one of X1-X4 is hydrophobic and/or at least one, and preferably all four of amino acids X1 and X4 found in the native forms are deleted; and/or one or more of X5r C8, Xg~
X12, C13 and X16 is absent. By suitable manipulation of these and other features, the range of conditions under which the 3~ class of protegrins of the present invention are effective can be varied. Furthermore, the spectrum of microbes against which they are effective can also be modified.

CA 02238610 1998-0~-22 W ~ 97118826 PCT~US96118~44 In another class, the peptides of the inveniton are comprised of about 10-14 amino acid residues and each of C8 and C13 is independently present or not present, and if present each is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of C6 and C15 is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of X1-X5 is independently present or not present, and if present each is independently a basic or small amino acid and any two of Xl-X5 may be a hydrophobic amino acid;
each of X7 and X14 is independently a hydrophobic amino acid;
each of X9 and X12 is independently present or not present, and if present each is independently a basic or hydrophobic amino acid;
X1~ is a basic, hydrophobic or small amino acid or proline;
X16 is present or not present, and if present is a basic, small or hydrophobic amino acid;
each of X17 and X18 is ;~ep~ndently present or not present, and if present each is independently a basic or small amino acid.
each of Xl6-Xl8 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large or small amino acid.

In another class, the peptides of the invention are comprised of about 10-18 amino acid residues and each of CB
and C13 is independently present or not present, and if present each is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of C6 and Cl5 is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of Xl-X4 is independently present or not present, and if present each is ;n~ep~n~ntly a basic or small amino acid and any one of Xl-X4 may be a hydrophobic amino acid;

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 each of X5 and Xl6 is independently present or not present, and if present each is idenpendently a hydrophobic or basic amino acid;
each of X7 and Xl4 is independently a hydrophobic amino acid;
X9 iS present or not present, and if present is a basic or hydrophobic amino acid;
X10 is a basic or small amino acid or proline;
Xll is a basic or hydrophobic amino acid;
Xl2 is present or not present, and if present is a hydrophobic amino acid;
Xl, present or not present, and if present is independently a small amino acid; and Xl8 is present or not present, and if present is a basic amino acid.
The invention peptides can be further illustrated by way of preferred embodiments. In one preferred embodiment of the invention, all of the cysteine-like amino acid residues at po6itions C6, C8, Cl3 and Cl5 are present as are Xg and Xl2.
In another set of preferred embodiments, all of Xl-X4 are not present. In another set of preferred embodiments, at least one, and preferably two of Xl-X4 is a hydrophobic amino acid, preferably I, V, L, Y, F or W.
In another set of preferred embo~; -nts, X9-xl2 contain at least one hydrophobic amino acid residue, preferably Phe, Tyr or Trp.
Other preferred embo~i ?nts include those peptides wherein each of X1 and Xg is independently selected from the group consisting of R, K, Orn, Dab and Har or hydrophobic;
preferably X1 is R, K, Har and Xg i5 R, K, Har or hydrophobic, especially I, V, L, W, F or Y. However, each of Xl and Xg may be absent.
In another class of preferred embodiments, each of X2 and X3 iS independently selected from the group consisting of G, A, S, T, I, V, L, F, Y and W; more preferably, X2 and X3 are G, W, F, Y, L, or V; however, X2 and/or X3 may be absent.
In another set of preferred embodiments, X4 is selected from the group consisting of R, K, H, Orn, Har, Dab, G, A, S, CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 T, F, Y and W; more preferably, X4 iS R, K, Orn, Dab, G or W;
however, X4 may be absent.
In another set of preferred embodiments, each of Xs and X16 is independently selected from the group consisting of I, - 5 V, L, Nle, W, Y, and F, preferably I, V, L, W, F and Y.
However, Xs and/or Xl6 may be absent.
In another set of preferred embodiments, each of X7 and Xl4 is independently selected from the group consisting of I, V, L, W, Y and F; preferably X7 iS I, F, Y or W and X14 is I, V, L, W, Y, or F.
In another set of pre~erred embo~; ~nts, X9 iS R, K, H, Orn, Dab, Har, I, V, L, Nle, W, Y or F, and X12 is I, L, V, W, F or Y; more preferably and aromatic amino acid such as Y, W, or F.
In another set of preferred embodiments, X10 is R, Orn, Dab, G, W or P.
In another set of preferred embodiments, Xll is R, K, Orn, Dab, G, W or P.
In another set of preferred embodiments, X17 is preferably absent, but when present, is preferably ~, A, S or T;
In another set of preferred embodiments, Xl8 is preferably absent, but when present, is preferably R, K, H, orn, Dab or Har.
Also preferable when all four amino acids X1-X4 are present, Xl and X4 are preferably basic and X2 and X3 are small or hydrophobic. Preferred embodiments of Xl-X4 include R-G-G-R, R-G-W-R, R-L-L-R and the like.
Preferred embodiments for the basic amino acid to replace cysteine-like residues are R, K, H, Orn, Dab and Har, most preferably R, K or orn. Preferred small amino acids to replace the cysteine-like residues include G, A, S and T, most preferably A and ~.
Particularly preferred peptides of the invention include the native, kite, bullet and/or snake forms of the following peptides:

CA 02238610 1998-0~-22 Form-21 R-G-G-R-L-Z-Y-Z-R-R-R-F-Z-V-Z-V
R-G-G-R-R-Z-Y-Z-R-R-R-F-Z-V-Z-V
R-G-G-R-L-Z-Y-Z-R-R-R-F-Z-V-Z-R
R-G-G-R-R-Z-Y-Z-R-R-R-F-Z-V-Z-R
R-Z-Y-Z-R-R-R-F-Z-V-Z-V
L-Z-Y-Z-R-R-R-F-Z-V-Z-R
R-Z-Y-Z-R-R-R-F-Z-V-Z-R
L-Z-Y-Z-R-R-R-F-Z-V-Z-V

Form-22 R-G-G-R-L-Z-Y-Z-R-R-R-F-Z-I-Z-V
R-G-G-R-R-Z-Y-Z-R-R-R-F-Z-I-Z-V
R-G-G-R-L-Z-Y-Z-R-R-R-F-Z-I-Z-R
R-G-G-R-R-Z-Y-Z-R-R-R-F-Z-I-Z-R
R-Z-Y-Z-R-R-R-F-Z-I-Z-V

R-Z-Y-Z-R-R-R-F-Z-I-Z-R
L-Z-Y-Z-R-R-R-F-Z-I-Z-V

Form-23 R-G-G-G-L-Z-Y-Z-R-R-R-F-Z-V-Z-V

R-G-G-G-L-Z-Y-Z-R-R-R-F-Z-V-Z-R
R-G-G-G-R-Z-Y-Z-R-R-R-F-Z-V-Z-R
R-Z-Y-Z-R-R-R-F-Z-V-Z-V
L-Z-Y-Z-R-R-R-F-Z-V-Z-R

L-Z-Y-Z-R-R-R-F-Z-V-Z-V

Form-24 R-G-G-R-L-Z-Y-Z-R-G-W-I-Z-F-Z-V
R-G-G-R-R-Z-Y-Z-R-G-W-I-Z-F-Z-V

R-G-G-R-R-Z-Y-Z-R-G-W-I-Z-F-Z-R
R-Z-Y-Z-R-G-W-I-Z-F-Z-V

L-Z-Y-Z-R-G-W-I-Z-F-Z-R
R-Z-Y-Z-R-G-W-I-Z-F-Z-R

Form-25 R-G-G-R-L-Z-Y-Z-R-P-R-F-Z-V-Z-V
R-G-G-R-R-Z-Y-Z-R-P-R-F-Z-V-Z-V

CA 02238610 1998-0~-22 W O 97/18826 PCTAUS96/18~44 R-G-G-R-L-Z-Y-Z-R-P-R-F-Z-V-Z-R
R-G-G-R-R-Z-Y-Z-R-P-R-F-Z-V-Z-R
R-Z-Y-Z-R-P-R-F-Z-V-Z-V
L-Z-Y-Z-R-P-R-F-Z-V-Z-R
R-Z-Y-Z-R-P-R-F-Z-V-Z-R
L-Z-Y-Z-R-P-R-F-Z-V-Z-V
and the N-acylated and/or C-amidated or esterified forms thereof wherein each Z is independently a hydrophobic, small or basic amino acid or cysteine, as well as the foregoing forms wherein X7 is W and/or X12 is W and/or wherein Xlq is W
and/or wherein X16 is W and/or wherein X17 is G and X18 is R;
and/or wherein at least one of X5 ~ Xg ~ X12 and X16 is not present. In all of these embodiments, Z is preferably S, A, T or G, most preferably A or T.
In the foregoing peptides, protegrin form 21 consists of compounds which are characteristic of the present class but which are otherwise similar to protegrin-l (PG-1); form 22 contains the characteristics of the present class but is otherwise similar to protegrin-2 (PG-2); forms 23 through 2~
are similarly related to protegrins -3, -4 and -5 (PG-3, PG-4 and PG-5) (see Figure 5).
Another set of preferred compounds includes the native, bullet, kite and snake forms of the following peptides (sequences are shown aligned to protegrin PG-1):

CODE S~Q~NCE
PG-1 RGG~LCYCRRRFCVCVGR (SEQ ID NO:1) WLCFCRRRFCVCV (SEQ ID NO:2) FLCFCRRRFCVCV (SEQ ID NO:3) WYCYCRRRFCVCV (SEQ ID NO:4) WXCYCRRRFCVCV ~X=Cha) (SEQ ID NO:5) WLCYCRRRF~v~v~K (SEQ ID NO:6) WXCYCRRRFCVCVGR (X=Cha) (SEQ ID NO:7) ~T.T,RT~YCRRRFCVCVGR (SEQ ID NO:8) RGGRLCYCRRRFCXCVGR (X=MeVal) (SEQ ID NO:9) RGVCVCFRRRCYCLW (SEQ ID NO:10) RGVCVCFRRRCYCLW (SEQ ID NO:11) CA 02238610 1998-0~-22 CODE SEQUENCE
VCVCFRRRCYCLW (SEQ ID NO:12) FCVCFRRRCFCLF (SEQ ID NO:13) RGVCVCFRRRCYCRGGR (SEQ ID NO:14) RGVCVCFRRRCYCLRGGR (all D) (SEQ ID NO:15) 5RGVCVCFRRRCYCLW (SEQ ID NO:16) RGVCVCYRXRCYCLW (X=MeGly) (SEO ID NO:17) WhCYCRXZYCVCVGR (X=MeGly) (SEQ ID NO:18) (Z=D-Arg) RGFCVCFRRVCYCLW (SEQ ID NO:l9) WLCYCRRRFCVCVGR (SEQ ID NO:20) 10WLCYCRRXFCVCVR (X=D-Arg) (SEQ ID NO:21) WLCYCKKKFCVCVGK (SEQ ID NO:Z2) Octyl-WLCYCRRRFCVCVGR (SEQ ID NO:23) XLCYCRRRFCVCV (X=1-Nal) (SEQ ID NO:24) WLC RGRF CVR (SEQ ID NO:25) WLC RGRF CFR (SEQ ID NO:26) WLCY RR VCVR (SEQ ID NO:27) WLCYCOOOFCVCV (SEQ ID NO:28) WLCYCXXXFCVCV (X=Dab) (SEQ ID NO:29) WLCYCRRRFCVCV (all D) (SEQ ID NO:30) HWRLCYCRPKFCVCV (SEQ ID NO:31) KWRLCYCRPKFCVCV (SEQ ID NO:32) OWRLCYCRPKFCVCV (SEQ ID NO:33) XWRLCYCRPKFCVCV (X=Dab) (SEQ ID NO:34) RWHLCYCRPKFCVCV (SEQ ID NO:35) RWKLCYCRPKFCVCV (SEQ ID NO:36) RWOLCYCRPKFCVCV (SEQ ID NO:37) RWXLCYCRPKFCVCV (X=Dab) (SEQ ID NO:38) WLCYCKXKFCVCVGR (X=Tic) (SEQ ID NO:39) FCYCKXKFCYCV (X=Hyp) (SEQ I3 NO:40) WLX~XK~FXVXV (X=hCys) (SEQ ID NO:41) WOLCYCOXOFCVCVO (X=Tic) (SEQ ID NO:42) OFCVCVOXOFCVCVO (X=Tic) (SEQ ID NO:43) OWOLCYCOXOFCVCV (X=Tic) (SEQ ID NO:44) OFCVCXOLCYCFO (X=Tic) (SEQ ID NO:45) CA 02238610 1998-0~-22 W O97~18826 PCT~S96/18544 CODESEQUENCE
WLCYCKKKFCVCV (SEQ ID NO:46) OWOLCYCOXOFCVCV (X=~YP) (SEQ ID NO:47) WLCYCOXOFCVCVO ( X=Pba) (SEQ ID NO:48) WLCYCOOOFCVCV (all D) (SEQ ID NO:49) XFCYCLRXFCVCVR (X=D-Arg) (SEQ ID NO:50) WLCYCRRXFCVCVZX (SEQ ID NO:51) (X=D-Arg) (Z=MeG1Y) PC11LCYCRRRFCVCVGR (SEQ ID NO:52) PCl2RCYCRRRFCVCV (SEQ ID NO:53) PC15RGGRLCYCRRRFCVCR ( SEQ ID NO:54) PC16RCYCRRRFCVCR (SEQ ID NO:55) PC17LCYCRRRFCVCV (SEQ ID NO:56) PC18LCYARRRFAVCV (SEQ ID NO:57) PCl9RCYARRRFAVCR ( SEQ TD NO:58) PC20LAYCRRRFCVAV ( SEQ ID NO:59) PC21RAYCRRRFCVAR (SEQ ID NO:60) PC22RGGRLCY RR VCV (SEQ ID NO:61) PC31GGRLCYCRRRFCVCV ( SEQ ID NO:62) PC32RGRLCYCRRRFCVCV ( SEQ ID NO:63) PC33GRLCYCRRRFCVCV ( SEQ ID NO:64) PC34RRLCYCRRRFCVCV (SEQ ID NO:65) PC35RLCYCRRRFCVCV ( SEQ ID NO:66) PC36RRCYCRRRFCVCV ( SEQ ID NO:67) PC37CYCRRRFCVCV (SEQ ID NO:68) PC44RGGRLCYCRRRFCVC (SEQ ID NO:69) PC47RGGRLCY RRRF VCV ( SEQ ID NO:70) PC48RGWRLCYCRRRFCVCV (SEQ ID NO:71) PC37aCYCRRRFCVCVGR (SEQ ID NO:72) PC45RGGRLCYCRRRFCV ( SEQ ID NO:73) PC72LCYCRRRFCVC (SEQ ID NO:74) PC64L~Y'1~KFTVCV (SEQ ID NO:75) PC64aLTYCRRRFCVTV (SEQ ID NO:76) PC3laGGRLCYCRRRFCVCVGR ( SEQ ID NO:77) PC32aRGRLCYCRRRFCVCVGR ( SEQ ID N~:78) CODE SEQUENCE
PC33a GRLCYCRRRFCVCVGR (SEQ ID NO:79) PC34a RRLCYCRRRFCVCVGR (SEQ ID NO:80) PC35a RLCYCRRRFCVCVGR (SEQ ID NO:81) PC36a RRCYCRRRFCVCVGR tSEQ ID NO:82) PC44a RGGRLCYCRRRFCVCR (SEQ ID NO:83) PC47a RGGRLCY RRRF VCVGR (SEQ ID NO:84) PC48a RGWRLCYCRRRFCVCVGR (SEQ ID NO:85) PC54 RGWRLAYCRRRFCVAVGR (SEQ ID NO:86) PC61 RCYCRRRFCVCV (SEQ ID NO:87) PC62 LCYCRRRFCVCR (SEQ ID NO:88) PC63 VCYCFRRFCYCV (SEQ ID NO:89) PC65 LCYTRPRFTVCV (SEQ ID NO:90) PC66 LCYTRGRFTVCV (SEQ ID NO:91) PC67 LCYFRRRFIVCV (SEQ ID NO:92) ~15 PC68 LCYFRPRFIVCV (SEQ ID NO:93) PC69 LCYTFRPRFVCV (SEQ ID NO:94) PC70 LCYTFRGRFVCV (SEQ ID NO:95) PC74 CYCFRRFCVC (SEQ ID NO:96) PC77 LCYCRRRRCVCV (SEQ ID NO:97) PC78 LCYCFRRRCVCV (SEQ ID NO:98) PC79 LCYCRFRRCVCV (SEQ ID NO:99) PC80 LCYCRRFRCVCV (SEQ ID NO:100) PC81 LCYCRRFFCVCV (SEQ ID NO:101) PC82 LCYCRFFRCVCV (SEQ ID NO:102) PC83 LCYCFFRRCVCV (SEQ ID NO:103) PC84 LCYCFRRFCVCV (SEQ ID NO:104) PC85 LCYCFRFRCVCV (SEQ ID NO:105) PC86 LCYCRFRFCVCV (SEQ ID NO:106) PC87 LCYCFRFFCVCV (SEQ ID NO:107) PC88 LCYCFFRFCVCV (SEQ ID NO:108) PC89 LCYCFFFRCVCV (SEQ ID NO:109) PC90 LCYCRFFFCVCV (SEQ ID NO:100) RGGRLCY RR VCVGR (SEQ ID NO:lll) PC91 YCYCRRRFCVCVGR (SEQ ID NO:112) CA 02238610 1998-0~-22 WO 97/18826 PCT~US96/18544 CODESEQUENCE
PC95ICYCRRRFCVCVGR (SEQ ID NO:113) PC96FCYCRRRFCVCVGR (SEQ ID NO:114) PC97WCYCRRRFCVCVGR (SEQ ID NO:115) PC99RCYCRRRFCVCVGR (SEQ ID NO:116) PC109RLCYTRGRFTVCV (SEQ ID NO:117) PC110LCYTRGRFTVCVR (SEQ ID NO:118) PC111RLCYTRGRFTVCVR (SEQ ID NO:119) PC112LCYCHHHFCVCV (SEQ ID NO:120) PC113L~Y~l~n~r~l~vCV (SEQ ID NO:121) RGGLCYCRRRFCVCVGR (SEQ ID NO:122) RGGRLCYCRRRFCVCVGR (SEQ ID NO:123) RGGGLCYCRRRFCVCVGR (SEQ ID NO:124) RGGGLCYCRRGFCVCFGR (SEQ ID NO:12~) RGGGLCYCRRPFCVCVGR (SEQ ID NO:126) RGGGLCYCRPRFCVCVGR (SEQ ID NO:127) RGGRLCYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:128) RGGLCYCRGRFCVCVGR (SEQ ID NO:129) RGGRLCYCXGRF~v~vG~ (X=Cit) (SEQ ID NO:130) XGGRLCYCRGRFCVCVGR (X=Cit) (SEQ ID NO:131) RGGRVCYCRGRFCVCVGR (SEQ ID NO:132) RGGGLCYCFPKFCVCVGR (SEQ ID NO:133) RGWGLCYCRPRF~v~v~K (SEQ ID NO:134) RGWRLCYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:135) RGWRLCYCRGRFCVCVGR (SEQ ID NO:136) RGWRLCYCXPRFCVCVGR (X=Cit) (SEQ ID NO:137) RWRLCYCRPRFCVCVGR (SEQ ID NO:138) RGWRLCYCRPRFCVCVGR (SEQ ID NO:139) RGWRACYCRPRFCACVGR (SEQ ID NO:140) GWRLCYCRPRFCVCVGR (SEQ ID NO:141) RWRLCYCKGXFCVCVGR (SEQ ID NO:142) RGWRLCYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:143) GGWRLCYCRGRFCVCVGR (SEQ ID NO:144) RGGWLCYCRGRFCVCVGR (SEQ ID NO:145) RLLRLCYCRXRFCVCVGR (X--MeGly) (SEQ ID NO:146) CA 02238610 1998-0~-22 CODE SEQUENCE
RLLRACYCRXRF~v~v~K (X=MeGly) (SEQ ID NO:147) RLLRLCYCRRRFCVCVGR (SEQ ID NO:148) RGLRXCYCRGRFCVCVGR (X=Cha) (SEQ ID NO:149) RGGRLCYCRXRZCVCWGR (X=MeGly) (SEQ ID NO:15~) (Z=Cha) RGGRWCVCRXRZCYCVGR (X=MeGly) (SEQ ID NO:151) (Z=Cha) RGLRXCYCRGRFCVCVGR (X=Cha) (SEQ ID NO:152) RGGRWCVCRGRXCYCVGR (X=Cha) (SEQ ID NO:153) RGGRLCYCRRRFCXCVGR (X=MeVal) (SEQ ID NO:154) LCYCRRRFCVCV (SEQ ID NO:155) LCYCRRCFCVCV (SEQ ID NO:156) LCYCRRRFCVCF (SEQ ID NO:157) LCACRRRACVCV (SEQ ID NO:158) LCYCRXRFCVCV (X=D-Arg) (SEQ ID NO:159) LCWCRRRFCVCV (SEQ ID NO:160) WCYCRRRFCVCV (SEQ ID NO:161) LCYCRRRXCVCV (X-hPhe) (SEQ ID NO:162) LCYCRRRXCVCV (X=Phe(4-Cl)) (SEQ ID NO:163) XCYCRRRFCVCV(X=Cha) (SEQ ID NO:164) LCYCRRRFCXCV (X=D-His) (SEQ ID NO:165) LCYCRRRXCVCV (X=MeGly) (SEQ ID NO:166) LCYCRRRXCVCV (X=MePhe) (SEQ ID NO:167) LCYCRRRFCXCV (X=MeVal) (SEQ ID NO:168) LCXCRRRXCVCV (X=Cha) (SEQ ID NO:169) LCGCRRRGCVCV (SEQ ID NO:170) LCACRGRACVCV (SEQ ID NO:171) RACYCRPRFCACV (SEQ ID NO:172) RLCYCRPRFCVCF (SEQ ID NO:173) RLCYCRPRFCVCV (SEQ ID NO:174) KLCYCKPKFCVCV (SEQ ID NO:175) RLCACRGRACVCV (SEQ ID NO:176) R~CYCRXRFCVCV (X=MeGly) (SEQ ID NO:177) RXCFCRPRFCVCV (X-Cha) (SEQ ID NO:178) RWCFCRPRFCVCV (SEQ ID NO:179) CA 02238610 1998-0~-22 W O 97/18826 PCT~US96~18544 CODE SEQUENCE
WLCYCRRRFCVCV (SEQ ID NO:180) WLCFCRRRFCVCV (SEQ ID NO:181) FLCFCRRRFCVCV (SEQ ID NO:182) WLCFCRRRXCVCV (X=MePhe) (SEQ ID NO:183) WYCYCRRRFCVCV (SEQ ID NO:184) WXCYCRRRFCVCV (X=Cha) (SEQ ID NO:185) RXCFCRGRZCVCV (X=Cha) (SEQ ID NO:186) (Z=MePhe) XLCFCRRRZCVCV (X=Cha) (SEQ ID NO:187) (Z=MePhe) RLCYCRPRFCVCVGR (SEQ ID NO:188) WLCYCRRRFCVCVGR (SEQ ID NO:189) WXCYCRRRFCVCVGR (X=Cha) (SEQ ID NO:190) RLCYCRGPFCVCR (SEQ ID NO:191) RRWCFVCYAGFCYRCR (SEQ ID NO:192) RRCYCRGRFCGCVGR (SEQ ID NO:193) RWRCYCGRRFCGCVGR (SEQ ID NO:194) RARCYCGRRFCGCVGR (SEQ ID NO:195) GWRCYCRGRFCGC (SEQ ID NO:196) RGWACYCRGRFCVC (SEQ ID NO:197) RRCYGRRRFGVCVGR (SEQ ID NO:198) RGWRLCYGRGRFKVC (SEQ ID NO:199) RGWRLCYCRGRFCVC (SEQ ID NO:200) CYCRRRFCVCF (SEQ ID NO:201) RGWRLCYCRXRFCVC (X--MeGly) (SEQ ID NO:202) RGWRGCYCRXRFCGC (X=MeGly) (SEQ ID NO:203) LCYCRPRFCVCVGR (SEQ ID NO:204) LCYCKPKFCVCVGK (SEQ ID NO:205) LCYCRGRFCVCVGR (SEQ ID NO:206) LCYCRPRFCVCVGRGR (SEQ ID NO:207) RRWCYCRPRFCVC~R (SEQ ID NO:208) WRLCYCRPRFCVCVGR (SEQ ID NO:209) GWLCYCRGRFCVCVGR (SEQ ID NO:210) RWLCYCRGRFCVCVGR (SEQ ID NO:211) RLLCYCRGRFCVCVGR (SEQ ID NO:212) CA 02238610 1998-0~-22 W O 97/18826 PCTrUS96/18544 CODE SEQUENCE
RWRLCYCRPRFCVCV (SEQ ID NO:213) RXRLCYCRZRFCVCV (X=Cha) (SEQ ID NO:214) (Z=MeGly) RGWRLCYCRGRXCVCV (X=Cha) (SEQ ID NO:215) RGGRVCYCRGRFCVCV (SEQ ID NO:216) LCYCRXRFCVCV (X=D-Ala) (SEQ ID NO:217) LCYCKPKFCVCV (SEQ ID NO:218) VCYCRPRFCVCV (SEQ ID NO:219) LCYCRPRFCVCW (SEQ ID NO:220) LCYRRPRFRVCV (SEQ ID NO:221) RGWRLCYCRGRXCVCV (X=Cha) (SEQ ID NO:222) RXRLCYCRZRFCVCV (X=Cha) (SEQ ID NO:223) (Z--MeGly) RXRLCYCRGRFCVCV (X=Cha) (SEQ ID NO:224) RGGGLCYARGWIAFCVGR (SEQ ID NO:225) RGGGLCYARGFIAVCFGR (SEQ ID NO:226) RGGGLCYARPRFAVCVGR (SEQ ID NO:227) RGGGLCYTRPRFTVCVGR (SEQ ID NO:228) RGGGLCYARKGFAVCVGR (SEQ ID NO:229) RGGRLCYARRRFAVCVGR (SEQ ID NO:230) RGGGLCYKRGFIKVCFGR (SEQ ID NO:231) RGGGLCYKRGWIKFCVGR (SEQ ID NO:232) RGGGLCYRLPKFRVCVGR (SEQ ID NO:233) RGGGLCYRLPGFRVCVGR (SEQ ID NO:234) RGWRGCYKRGRFKGCVGR (SEQ ID NO:235) LCYKRGRFKVCV (SEQ ID NO:236) ICYRPR~v~v~ (SEQ ID NO:Z37) WLCYCRRRFCVCV (SEQ ID NO:238) RLCYCRRRFCVCV (SEQ ID NO:240) ~GRVCLRYCRGRFCVRLCFR (SEQ ID NO:241) RRRLCYCRRRFCVCVGR (SEQ ID NO:242) and the N-acylated and/or C-amidated or esteri~ied forms thereof.

CA 02238610 1998-0~-22 W O 97~8826 PCT~US96J18544 6.2.2 PreParation of the com~ounds The invention compounds, often designated herein "protegrins" are essentially peptide backbones which may be modified at the N- or C-terminus and also may contain~ 5 one or two disulfide linkages. The peptides may first be synthesized in noncyclized form. These peptides may then be converted to the cyclic peptides if desired by st~n~Ard methods of disulfide bond formation. As applied to the protegrins herein, "cyclic forms" refers to those forms which contain cyclic portions by virtue of the formation of disulfide linkages between cysteine-like amino acid residues in the peptide. If the non-cyclized forms are preferred, it is preferable to stabilize the sulfhydryl groups for any peptides of the invention which contain two or more cysteine-like residues.
St~n~d methods of synthesis of peptides of the sizesdescribed herein are known. Most commonly used currently are solid phase synthesis techniques; in~e~ automated equipment for systematically constructing peptide ~~.h;~; n!: can be purchased. Solution phase synthesis can also be used and has considerable benefits for large scale production. When synthesized using these st~n~d techniques, amino acids not encoded by the gene and D-enantiomers can be employed in the synthesis. Thus, one very practical way to obtain the compounds of the invention is to employ these st~n~rd chemical synthesis techn;ques.
In addition to providing the peptide backbone, the N-and/or C-terminus can be derivatized, again using conventional chemical techn;ques. The compounds of the invention may optionally contain an acyl group at the amino terminus. Methods for acetylating or, more generally, acylating, the free amino group at the N-teL ;nn~ are generally known in the art; in addition, the N-terminal amino acid may be supplied in the synthesis in acylated form.
3~ At the carboxyl terminus, the carboxyl group may, of course, be present in the form of a salt; in the case of pharmaceutical compositions this will be a pharmaceutically acceptable salt. Suitable salts include those formed with CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18~44 inorganic ions such as NH4~, Na+, K~, Mgt~, Ca'~, and the like as well as salts formed with organic cations such as those of caffeine and other highly substituted amines. However, when the compound of formula (I) contains a multiplicity of basic residues, salt formation may be difficult or impossible. The carboxyl terminus may also be esterified using alcohols o~
the formula ROH wherein R is hydrocarbyl as defined above~
Similarly, the carboxyl terminus may be amidated so as to have the formula -CONH2, -CONHR, or -CONR2, wherein each R is independently hydrocarbyl as herein defined. Techni~ues for esterification and amidation as well as neutralizing in the presence of base to form salts are all standard organic chemical t~çhn;ques.
If the peptides of the invention are prepared under physiological conditions, the side-chain amino groups of the basic amino acids will be in the form of the relevant acid addition salts.
For synthesis of linear peptide with a C-terminal amide, the peptide sequence is conveniently synthesized on a Fmoc Rink amide solid support resin (Bachem) using Fmoc chemistry on an automated ABI g33 peptide synthesizer (ABD, Perkin Elmer, Foster City, CA) according to the manu~acturer~s st~n~rd protocols. Cleavage is typically carried out in 10 ml of thioanisole/EDT/TFA (1/1/93 for 2 hours at room temperature. Crude cleavage product is precipitated with t-butyl methyl ether, filtered and dried.
Formation of disulfide linkages, if desired, is conducted in the presence of mild oxidizing agents. Chemical oxidizing agents may be used, or the compounds may simply be exposed to the oxygen of the air to effect these linkages.
Various methods are known in the art. Processes use~ul for disulfide bond formation have been described by Tam, J.P. et al., Synthesis (1979) 955-957; Stewart, J.M. et al., Solid Phase PePtide SYnthesis, 2d Ed. Pierce Chemical Company Rock~ord, IL (1984); Ahmed A.K. et al., J Biol Chem (1975) 250:8477-8482 and Pennington M.W. et al ., Peptides 19gO , E.
Giralt et al., ESCOM Leiden, The Netherlands (1991) 164-166.
An additional alternative is described by Kamber, B. et al ., W O 97/18826 PCT~US96/18544 Helv Chim Acta (1980) 63:899-915. A method conducted on solid supports is described by Albericio, Int ~ Pept Protein Res (1985) 26:92-97.
A particularly preferred method is solution oxidation using molecular oxygen. This method has been used by the inventors herein to refold synthetic PG-1, PG-3 in its amide or acid forms, enantio PG-1 and the two unidisulfide PG-l compounds (C6-C1s and C8-C13). Recoveries are as high as 65-90% .
In this preferred method to form disulfide linkages, the crude peptide is dissolved in DMSO and added to 20 mM
ammonium acetate buffer, pH 7. The final concentration of the peptide in the solution is between 1-8 mg/ml, the pH ranges from 7.0-7.2, and the DMSO concentration ranges from 5-20%.
1~ The peptide solution is stirred overnight at room temperature.
The pE of the solution is adjusted to pH5 with concentrated acetic acid and the sample purified on Prep LC.
After loading, the column is washed with 10% acetonitrile/H20 (0.1% TFA) until the W absorbance decreases to the baseline.
The gradient is then started.
Column: Vydac Cat#218TP101522, 2.2 x 25 cm, C18 peptides & proteins; W ~: 235 nm; Flow Rate: 10 ml/min.
Solvent A is 100% 0.1% TFA/H2O; Solvent B is 100% 0.08%
T~A/ACN. The gradient is as follows.

T (min) %B (l; neA~ gradient) Fractions are analyzed by analytical EPLC and those that contain the desired peptide are combined. The acetonitrile is stripped and the resulting aqueous solution lyophilized.
The resulting amide, cont~;n;ng sulfide bonds, is con~irmed by mass spectrum.

CA 02238610 1998-0~-22 I~ the peptide backbone is comprised entirely of gene-encoded amino acids, or if some portion of it is so composed, the peptide or the relevant portion may also be synthesized using recombinant DNA techniques. The DNA encoding the peptides of the invention may itself be synthesized using commercially available equipment; codon choice can be integrated into the synthesis depending on the nature of the host.
Recombinantly produced forms of the protegrins may require subsequent derivatization to modify the N- and/or C-teL ;~u~ and, dep~n~i n~ on the isolation procedure, to effect the formation of disulfide bonds as described hereinabove. Depending on the host organism used for recombinant production and the animal source from which the protein is isolated, some or all of these conversions may already have been ef~ected.
For recombinant production, the DNA ~coA; ng the protegrins of the invention is included in an expression system which places these coding sequences under control of a suitable promoter and other control sequences compatible with an intended host cell. Types of host cells available span almost the entire range of the plant and animal kingdoms.
Thus, the protegrins of the invention could be produced in bacteria or yeast (to the extent that they can be produced in 2~ a nontoxic or refractile form or utilize resistant strains) as well as in Ani ~- cells, insect cells and plant cells.
Indeed, modified plant cells can be used to regenerate plants cont~;ning the relevant expression systems so that the resulting transgenic plant is capable of self protection vis-~-vis these infective agents.
The protegrins of the invention can be produced in a form that will result in their secretion from the host cell ~y fusing to the DNA enco~;ng the protegrin, a ~NA encoding a suitable signal peptide, or may be produced intracellularly.
They may also be produced as fusion proteins with additional amino acid se~uence which may or may not need to be subse~uently removed prior to the use of these compounds as antimicrobials or antivirals.

WO g7/188Z6 PCT~US96/18544 Thus, the protegrins of the invention can be produced in a variety of modalities including chemical synthesis and recombinant production or some combination of these tPchn;ques.
Any members of the protegrin class which occur naturally are supplied in purified and/or isolated form. By l'purified and/or isolated" is meant free from the envi.o ~nt in which the peptide normally occurs (in the case of such naturally occurring peptides) and in a form where it can be used practically. Thus, "purified and/or isolated" form means that the peptide is substantially pure, i.e., more than 90%
pure, preferably more than 95~ pure and more preferably more than 99~ pure or is in a completely different context such as that of a pharmaceutical preparation.
6.2.3 Antibodies Antibodies to the protegrins of the invention may also be produced using st~n~rd immunological t~chn;ques for production of polyclonal antisera and, if desired, immortalizing the antibody-producing cells of the immunized host for sources of monoclonal antibody production.
Techniques for producing antibodies to any substance of interest are well known. It may be necessary to enhance the immunogenicity of the substance, particularly as here, where the material is only a short peptide, by coupling the hapten to a carrier. Suitable carriers for this purpose include substances which do not th~ ;clves produce an immune response in the mammal to be ~ ; n; ~tered the hapten-carrier conjugate. C~ ~n carriers used include keyhole limpet hemocyanin (KLH), diphtheria toxoid, serum albumin, and the viral coat protein of rotavirus, VP6. Coupling of the hapten to the carrier is effected by st~ rd t~c-hn; ques such as contacting the carrier with the peptide in the presence of a dehydrating agent such as dicyclohexylcarbodiimide or through the use of linkers such as those available through Pierce Chemical Company, Chicago, IL.
The protegrins of the invention in immunogenic form are then injected into a suitable mammalian host and antibody CA 02238610 1998-0~-22 titers in the serum are monitored. It should be noted, however, that some forms of the protegrins require modification before they are able to raise antibodies, due to their resistance to antigen processing. For example, the native form of PG-1, containing two disulfide bridges is nonimmunogenic when a~in;stered without coupling to a larger carrier and was a poor immunogen even in the presence of potent adjuvants and when coupled through glutaraldehyde or to K~H. Applicants believe this to be due to its resistance to attack by leukocyte serine proteases (human PMN elastase and cathepsin G) as well as to attack by an aspartic protease (pepsin) that resembles several macrophage cathepsins. The lack of immunogenicity may therefore result from resistance to processing to a linear form that can fit in the antigen-presenting pocket of the presenting cell. Immunogenicity of these forms o~ the protegrins can be enhanced by cleaving the disulfide bonds. However, the immunogenicity can be enhanced using the MAPS t~chn;que recently reported by Huang, W et ~1., Mol Immunol ~1994) 15:1191-1199 Po~yclonal antisera may be harvested when titers are sufficiently high. Alternatively, antibody-producing cells of the host such as spleen cells or peripheral blood lymphocytes may be harvested and immortalized. The immortalized cells are then cloned as individual colonies and screened for the production of the desired monoclonal ant; hoAi es.
Reco hinant t~chn;ques are also available for the production of antibodies, and thus, the antibodies of the invention include those that can be made by genetic engineering t~chn;ques. For example, single-chain forms, such as Fv forms, ch; -~ic antibodies, and antibodies modified to mimic those of a particular species, such as humans, can be produced using standard methods. Thus, the antibodies of the invention can be prepared by isolating or modifying the genes encoding the desired antibodies and producing these through expression in recombinant host cells, such as CH0 cells.

CA 02238610 1998-0~-22 WO 97/18826 PCT~US96J18544 The antibodies of the invention are, of course, useful in immunoassays ~or determining the amount or presence of the protegrins. Such assays are essential in quality controlled production of compositions cont~;ning the protegrins of the invention. In addition, the antibodies can be used to assess the efficacy of recombinant production of the protegrins, as well as scr~;ng expression libraries for the presence of protegrin encoding genes.

6.2.4 ~omPositions containinq the Proteqrins and Methods of Use The protegrins of the invention are effective in inactivating a wide range of micro~ial and viral targets, including Gram-positive and Gram-negative bacteria, yeast, protozoa and certain strains of virus. Because of their broad spectrum of activities, the protegrins of the invention can be used as preservatives as well as in treatment and prophylactic contexts.
They are bactericidal against Gram-positive bacteria which include major pathogens, such as Staphylococcus aureus, including MRSA (the methicillin resistant version) and MSSA
(the methicillin-sensitive strain), and Enterococcus faecium and E. faecalis (including VREF or vancomycin resistant E. faecium) and VSEF or vancomycin-sensitive E. faecalis).
These are very common pathogens in hospital settings. Other Gram-positive bacteria which are suitable targets include Listeria monocytogenes, Streptococcus pneumoniae ( including PRSP, the penicillin resistant form), S. mitis, S. sanguis, Staphylococcus epidermis ( including methicillin sensitive strain MSSE), S. salivarius, Corynebacterium minutissium, C.
pseudodiphtheriae, c. striatum, Corynebacterium groups Gl and G2, and Bacil l us subtil is . PRSP is also a wide-spread health hazard.
Among Gram-negative organisms against which the protegrins are effective are Escherichia coli, Pseudomonas aeruginosa, ~le~siella pneumoniae, Serratia marcescens, Haemophilus influenzae, Salmonel7a tyr~i rium, Acinetobacter calocoaceticus, C. pneumoniae, and Neisseria meningitidus, as CA 02238610 1998-0~-22 well as other species including those within the genera represented above. For example, Neisseria gonorrhoeae is ~ssociated with sexually transmitted diseases (STDs) as is Chlamydia trachomatis. Also among the Gram-negative orgAnis~ are the gastric pathogens Hel1cobacter pylori, H. felis, and Campylo~acter jejuni.
Besides Gram-positive and Gram-negative bacteria, the protegrins of the invention are also effective against growth and infection by mycobacteria such as M. tuberculosls and M. avium (including MAC); fungi, such as Candida albicans and the related pathogens, C. parapsilosis, C. krusei, C. tropicalis and C. glabrata, as well as Aspergillus niger.
Among the viruses against which the protegrins are effective are Herpes simplex I and II and Human immunodeficiency virus (HIV).
The foregoing is not an exhaustive, but representative list.
As stated above, the protegrins can also be used in disinfectant compositions and as preservatives for materials such as foodstuffs, cosmetics, medicaments, or other materials contAin;ng nutrients for orgAn;! ~. For use in such contexts, the protegrins are supplied either as a single protegrin, in admixture with several other protegrins, or in admixture with additional antimicrobial agents. In general, as these are preservatives in this context, they are usually present in relatively low amounts, of less than 5%, by weight of the total composition, more preferably less than 1%, still more preferably less than 0.1%.
The peptides of the invention are also useful as standards in antimicrobial assays and in assays for determination of capability of test compounds to bind to endotoxins such as lipopolysaccharides.
For use as antimicrobials or antivirals for treatment of animal subjects, the protegrins of the invention can be formulated as pharmaceutical or veterinary compositions.
Depending on the subject to be treated, the mode of administration, and the type of treatment desired -- e.g., prevention, prophylaxis, therapy; the protegrins are CA 02238610 1998-0~-22 W O 97/18826 PCTrUS96118544 formulated in ways consonant with these parameters. A
Sl ~ry of such t~chn;ques is found in Remington's Pharmaceutical Sciences, latest edition, Mac~ Publishing co., Easton, PA.
The protegrins can be used in animal subjects both as therapeutic and prophylactic treatments; by "treating" an infection is meant either preventing it from occurring, ameliorating the symptoms, inhibiting the growth of the microbe in the subject, and any other negative effect on the microbe which is beneficial to the subject. Thus, "treating"
or ~treatment~ have both prophylactic and therapeutic aspects.
The protegrins are particularly attractive as an active ingredient in pharmaceutical compositions useful in treatment of sexually transmitted diseases, including those caused by Chlamydia trachomatis, ~reponema palli~um, Neisseria gonorrhoeae, Trichomonas vaginalis, Herpes simplex type 2 and HIV. Topical formulations are preferred and include creams, salves, oils, powders, gels and the like. Suitable topical excipients are well known in the art and can be adapted for particular uses by those of ordinary skill.
In general, for use in therapy or prophylaxis of STDs, the protegrins of the invention may be used alone or in combination with other antibiotics such as erythromycin, tetracycline, macrolides, for example azithromycin and the cephalosporins. Depending on the mode of administration, the protegrins will be formulated into suitable compositions to permit facile delivery to the affected areas. The protegrins may be used in forms cont~;n;ng one or two disulfide bridges or may be in linear form. In addition, use of the enantiomeric forms containing all D-amino acids may confer advantages such as resistance to those proteases, such as trypsin and chymotrypsin, to which the protegrins conta;n;ng L-amino acids are less resistant.
The protegrins of the invention can be a~ ' n; ~tered singly or as mixtures of several protegrins or in combination ~ with other pharmaceutically active components. The formulations may be prepared in a manner suitable for CA 02238610 1998-0~-22 W O 97118826 PCT~US96/18544 systemic administration or topical or local aciri n;stration.
Systemic formulations include those designed for injection (e.g., intramuscular, intravenous, intraperitoneal or subcutaneous injection~ or may be prepared for transdermal, transmucosal, or oral a~;n;stration. The formulation will generally include a diluent as well as, in some cases, adjuvants, buffers, preservatives and the like. The protegrins can be administered also in liposomal compositions or as microemulsions.
If administration is to be oral, the protegrins of the invention should be protected from degradation in the digestive tract using a suitable enteric coating. This may be avoided to some extent by utilizing amino acids in the D-configuration, thus providing resistance to protease. The protegrins are relatively acid stable, however, some degree of enteric coating may still be required.
The protegrins of the invention retain their activity ~gainst microbes in the context of borate solutions that are commonly used in eye care products. It has also been shown that when tested for antimicrobial activity against E. coli in the presence and absence of lysozyme in borate buffered saline, that the presence of lysozyme ~nhAnced the effectiveness of PG-3. This effect was more pronounced when the PG-3 was autoclaved and similar patterns were obtained for both the ~ree-acid form and the amide. Accordingly, the protegrins may be used as preservatives in such compositions or as antimicrobials for treatment of eye infections, such as conjunctivitis and corneal ulcers.
It is particularly important that the protegrins retain their activity under physiological conditions including relatively high salt and in the presence of serum. In addition, the protegrins are dramatically less cytotoxic with respect to the cells of higher organisms as compared with their toxicity to microbes. These pr~perties, described 3~ hereinbelow in the Examples, make them particularly suitable for in vivo and therapeutic use.
As the examples will show, by appropriately choosing the member of the protegrin class of the invention, it is WO 97~18826 PCTAUS96118544 possible to adap~ the antimicrobial activity to ~; ;7e its effectiveness with respect to a particular target microbe.
As used herein, "microbe" will be used to include not only yeast, bacteria, and other unicellular orgAn;~ ~, but also viruses. For example, PC-l9 is particularly effective, as co~p~red to PG-l, under certain conditions. The particular protegrin can also be chosen to be advantageous in a particular context, such as low salt or physiological salt, the presence or human serum, or conditions that mimic the conditions found in blood and tissue fluids.
The protegrins of the invention may also be applied to plants or to their environment to prevent virus- and microbe-induced diseases in these plants. Suitable compositions for this use will typically contain a diluent as well as a spreading agent or other ancillary agreements beneficial to the plant or to the environment.
Thus, the protegrins of the invention may be used in any context wherein an antimicrobial and/or antiviral action is required. This use may be an entirely in vitro use, or the peptides may be a~~ ; n; ~tered to orgAn;~ -.
In addition, the antimicrobial or antiviral activity may be generated in situ by administering an expression system suitable for the production of the protegrins of the invention. such expression systems can be supplied to plant and animal subjects using known t~chn;ques. For example, in ~ , pox-based expression vectors can be used to generate the peptides in situ. Similarly, plant cells can be transformed with expression vectors and then regenerated into whole plants which are capable of their own production of the peptides.
The protegrins are also capable of inactivating endotoxins derived from Gram-negative bacteria -- i.e., lipopolysaccharides (LPS) -- in stAn~Ard assays.
Accordingly, the protegrins may be used under any circumstances where inactivation of LPS is desired. One such situation is in the treatment or amelioration of ~ram-negative sepsis.

_ CA 02238610 1998-0~-22 W O 97/13826 PCT~US96/18S44 6.2.5 Conditions Relevant to Antimicrobial/Antiviral ActivitY
It has been stated above that as used herein 'lantimicrobial" activity refers to inhibition with respect both to traditional microorganisms and to viruses, although occasionally, llantimicrobiali' and 'lantiviral'l are both specifically indicated.
A particularly useful property of the protegrins is their activity in the presence of serum. Unlike defensins, protegrins are capable of exerting their antimicrobial effects in the presence of serum.
Media for testing antimicrobial activity can be designed to mimic certain specific conditions. The standard buffer medium, medium A, uses an underlay agar with the following composition: 0.3 mg/ml of trypticase soy broth powder, 1%
w/v agarose and 10 mM sodium phosphate buffer (final p~ 7.4).
This will be designated either llmedium A" or llst~n~rd in vitro conditionsll herein.
All of the remaining media contain these same components. However, in addition:
A second medium contains lOo mM NaCl in order to mimic the salt levels in blood and tissue fluids. This will be designated "medium Bll or llsalt mediumll herein.
A third medium is supplemented with 2.5% normal human serum; however, it is of low ionic strength and thus does not mimic body fluids. This medium will be designated "medium C"
or 'Iserum-cont~;ning mediumll herein.
A fourth medium contains 80% RPMI-1640, a standard tissue culture medium which contains the principal ions and amino acids found in blood and tissue fluids. In addition, it contains 2.5% normal human serum. This will be designated 'medium Dll or 'Iphysiological mediumll herein.
Other media useful for testing antimicrobial properties are provided in the Examples.

CA 02238610 1998-0~-22 WO 97/18826 PC'r~US96/18~i44 6.2.6 Speci~ic Indications Certain of the protegrins of the invention have been found to be particularly effective in treating certain indications. For example, in treating microbial infections where the infectious agent is Staphylococcus aureus, particularly methicillin resistant strains, applicants have found the amides of the formulae:
RGWRLCYCRPRFCVCVGR (SEQ ID NO:139) GWRLCYCRPRFCVCVGR (SEQ ID NO:141) XCYCRRRFCVCVGR (X = Cha) (SEQ ID NO:164) WLCYCRRRFCVCV (SEQ ID NO:180) to be particularly effective. Also preferred is the free-acid form of WLCYCRRRFCVCV (SEQ ID NO:180).
In treating Pseudomonas infection, applicants have found the following amides to be effective:
RGGRLCYCRRRFCVCVGR (SEQ ID NO:1) RGGRLCYCRPRFCVCVGR (SEQ ID NO:239) RGGGLCYTRPRFTVCVGR (SEQ ID NO:228) Also effective is the free-acid form of the peptide RLCYCRRRFCVCV (SEQ ID NO:66).
Finally, in treating infections caused by H.pylori, applicants have found the following compounds in the amide form to be particularly effective:
WLCYCRRRFCVCV (SEQ ID NO:180) RXCFCRPRFCVCV (X=Cha) (SEQ ID NO:178) RG&RLCYCRRRFCVCVGR (SEQ ID NO:1) RGWGLCYCRPRFCVCVGR (SEQ ID NO:134) RLCYCRPRFCVCVGR (SEQ ID NO:138) RGWRLCYCRGRFCVCVGR (SEQ ID NO:136) RGRVCLRYCRGRFCVRLCFR (SEQ ID NO:241) RGLRXCYCRGRFCVCVGR (X=Cha) (SEQ ID NO:149) GWRLCYCRPRFCVCVGR (SEQ ID NO:139) RLCYCRRRFCVCV (SEQ ID NO:66) WLCYCXXXFCVCV (X=Dab) (SEQ ID NO:29) OWRLCYCRPKFCVCV (SEQ ID NO:33) RWOLCYCRPKFCVCV (SEQ ID NO:37) RRCYCRRRFCVCVGR (SEQ ID NO:82) XCYCRRRFCVCV (X=Cha) (SEQ ID NO:164) 45 Also effective are the free-acid and enantio (all-D) forms of the peptide RRRLCYCRRRFCVCVGR (SEQ ID NO:240).

CA 02238610 1998-0~-22 W O 97/18826 PCTnJS96/18544 6.3 ~ffective Dosaqes The peptides of the invention, or compositions thereof, will generally be used in an amount effective to achieve the intended purpose. Of course, it is to be understood that the amount used will depend on the particular application.
For example, for use as a disinfectant or preservative, an antimicrobially effective amount of a peptide, or composition thereof, is applied or added to the material to be disinfected or preserved. By antimicrobially effective amount is meant an amount of peptide or composition that inhibits the growth of, or is lethal to, a target microbe population. While the actual antimicrobially effective amount will depend on a particular application, for use as a disinfectant or preservative the peptides, or compositions thereof, are usually added or applied to the material to be disinfected or preserved in relatively low amounts.
Typically, the peptide comprises less than about 5% by weight of the disinfectant solution or material to be preserved, preferably less than about 1% by weight and more preferably less than about 0.1% by weight. An ordinarily skilled artisan will be able to determine antimicrobially effective amounts of particular peptides for particular applications without undue experimentation using, for example, the in vltro assays provided in the examples.
For use to treat or prevent microbial infections or diseases related thereto, the peptides of the invention, or compositions thereof, are Al' i n; ctered or applied in a therapeutically effective amount. By therapeutically effective amount is meant an amount effective top ameliorate the symptoms of, or ameliorate, treat or prevent microbial infections or diseases related thereto. Determination of a therapeutically effective amount is well within the capabilities of those s~illed in the art, especially in light of the detailed disclosure provided herein.
As in the case of disinfectants and preservatives, for topical administration to treat or prevent bacterial, yeast, fungal or other infections a therapeutically effective dose CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 can be determined using, for example, the in vitro assays provided in the examples. The treatment may be applied while the infection is visible, or even when it is not visible. An ordinarily skilled artisan will be able to determine therapeutically effective amounts to treat topical infections without undue experimentation.
For systemic a~ ;n;~tration, a therapeutically effective dose can be estimated initially from in vltro assays. ~or example, a dose can be formulated in animal models to achieve a circulating peptide concentration range that includes the ICso as dete~ ; ne~ in cell culture (i .e ., the concentration of test compound that is lethal to 50% of a cell culture), the MIC, as determined in cell culture (i.e., the minimal inhibitory concentration for growth3 or the IC1oo as determined in cell culture (i .e., the concentration of peptide that is lethal to 100% of a cell culture). Such information can be used to more accurately determine useful doses in humans.
Initial dosages can also be estimated from ln vivo data, e.g., ~n; ~1 models, using techn;ques that are well known in the art. One having ordinary skill in the art could readily optimize administration to humans based on animal data.
Dosage amount and interval may be adjusted individually to provide plasma levels of the active peptide which are sufficient to maintain therapeutic effect. Usual patient dosages for administration by injection range from about 0.1 to 5 mg/kg/day, preferably from about 0.5 to 1 mg/kg/day.
Therapeutically effective serum levels may be achieved by A~ ' ; n; stering multiple doses each day.
In cases of local administration or selective uptake, the effective local concentration of peptide may not be related to plasma concentration. One having skill in the art will be able to optimize therapeutically effective local dosages without undue experimentation.
3S The amount of peptide a inistered will, of course, be dependent on the subject being treated, on the subject's - weight, the severity of the affliction, the manner of administration and the judgment of the prescribing physician.

CA 02238610 1998-0~-22 W O 97tl8826 PCT~US96/18S44 The antimicrobial therapy may be repeated intermittently while lnfections are detectable or even when they are not detectable. The therapy may be provided alone or in combination with other drugs, such as for example antibiotics or ot~er antimicrobial peptides.

6.4 ToxicitY
Preferably, a therapeutically effective dose of the peptides described herein will provide therapeutic benefit without causing substantial toxicity.
Toxicity of the peptides described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the LDso (the dose lethal to 50% of the population) or the LDlco (the dose lethal to 100% of the population). The dose ratio between toxic and therapeutic effect is the therapeutic index. Compounds which exhibit high therapeutic indices are preferred. The data obtained from these cell culture assays and ~n; ~1 studies can be used in formulating a dosage range that is not toxic for use in human. The dosage of the peptides described herein lies preferably within a range of circulating concentrations that include the effective dose with little or no toxicity. The dosage may vary within this range depending upon the dosage form employed and the route of a~ ;nictration utilized. The exact formulation, route of a~ ;ni~tration and dosage can be chosen by the individual physician in view of the patient~s condition. ~See, e.g., Fingl et al., 1975, In: The Pharmacoloqical Basis of Thera~eutics, Ch.l, p.1).

SummarY
The protegrins therefore represent a peculiarly useful class of compounds because of the following properties:
1) They have an antimicrobial effect with respect to a broad spectrum of target microbial systems, including viruses, including retroviruses, bacteria, fungi, yeast and protozoa.

CA 02238610 1998-0~-22 W097/18826 PCT~US96~18~44 2) Their antimic~obial activity is effective under physiological conditions - i.e., physiological saline and in the presence of serum.
3) They are markedly less toxic to the cells of higher organisms than to microbes.
4) They can be prepared in non; lnogenic form thus ext~n~;ng the number of species to which they can be administered.
5) They can be prepared in forms which are resistant to certain proteases suggesting they are antimicrobial even in lysosomes.
6) They can be modified in amino acid sequence so as to optimize the specificity with respect to target.

7) They can be modified structurally so as to accommodate the conditions under which antimicrobial activity is to be exhibited.

The following examples are intended to illustrate but not to limit the invention.

~m~le 1: Isolation and ActivitY of PG-1, PG-2 and PG-3 As described in PCT/US94/08305, referenced above, three antimicrobial peptides were isolated from porcine leukocytes having the amino acid sequences:
PG-1: RGGRLCYCRRRFCVCVGR
PG-2: RGGRLCYCRRRFCICV
PG-3: RGGGLCYCRRRFCVCVGR, which are amidated at the C-terminus.
These particular protegrins were tested for antimicrobial activity.
It was shown that PG-1 and PG-3 are more effective against E. coli ML-35P than human neutrophil peptide ~NP-1 and only slightly less effective than rabbit defensin NP-1.
PG-1 and PG-3 were also effective against Listeria monocytogenes, strain EGD and against Candida albicans. In general, these peptides are approximately as effective as rabbit defensin NP-1 on a weight basis and are more effective CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18S44 than HNP-1. In all cases, PG-2 was also effective against the three organisms tested, but was not as active as the other two peptides.
PG-1 has also been shown directly to inhibit the growth of Stap~ylococcus aureus and K. pneumoneae 270. HNP-1 used as a control was less effective against S. aureus and almost entirely ineffective against ~. rner7~oneae.
The protegrins have also been tested against various other organisms and show broad spectrum activity. In addition to their effectiveness in inhibiting the growth of or infection by microorganisms associated with STDs, the protegrins show strong activity against the following microorganisms in addition to those tested hereinabove:
Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella ty~h;ml~rium, Staphylococcus aureus, Histoplasma capsulatum, Myobacterium avium-intracellulare, and Mycobacterium tuberculosis. The protegrins showed only fair activity against Vlbrio vulnificus and were inactive against Vibrio c~olerae and Borrelia burgdorferi.
The three protegrins described above retain their activity in the contexts of a variety of reaction conditions, including the presence of 100 mM NaCl and the presence of 90 fetal calf serum.
The protegrins have a spectrum of retention of antimicrobial properties under useful physiological conditions, including isotonic and borate solutions appropriate for use in eye care products.
PG-1 and PG-3 retain their activity with respect to C. albicans and E. coli respectively, in the presence of 100 mM NaCl. Neither NP-1 nor HNP-1 have this property.
Although NP-l and NHP-2 lose their ability to inhibit C. al~icans in 90% fetal calf serum, inhibition by PG-3 is retained.
The protegrins show varying patterns of activity when reaction conditions are altered. Synthetic PG-l was tested against E. coli ML-3~ (serum sensitive) in underlayered gels containing only 10 mM sodium phosphate buffer, pH 7.4 and a 1:100 dilution of trypticase soy broth, both in the presence CA 02238610 1998-0~-22 WO 97/18826 ~CT~US961I8544 and absence of 2.5% normal human serum, which is below the lytic concentration for this strain of E. coli. In the presence of serum, the i n; ~1 bactericidal concentration was reduced from approximately 1.0 ~g/ml to about 0.1 ~g/ml.
This type of effect was not observed either for a linear fragment of cathepsin G or for the defensin HNP-l.
Similarly, using C. albicans as a target organism, underlayers were prepared with 10 mM sodium phosphate with and without 10~ normal human serum. The ~;n; ~1 fungicidal co~c~ntration fell from about 1.3 ~g/ml in the absence of serum to 0.14 ~g/ml in its presence. The serum itself at this concentration did not effect C. albicans. Similar results were obtained using L. monocytogenes as the target organism.
The protegrins PG-1 and PG-3 were incubated for 4 hours at pH 2.0 with 0.5 ~g/ml pepsin and then neutralized. The residual antimicrobial activity against C. albicans, E. coli and L. monocytogenes was assessed and found to be fully retained. Similar experiments show that these compounds are not degraded by human leukocyte elastase or by human leukocyte cathepsin G even when exposed to high concentrations of these enzymes and at a pH of 7.0 - 8.0 favorable for proteolytic activity. In addition, synthetic PG-3 amide and synthetic PG-3 acid were autoclaved and tested for antimicrobial activity against E. coli, L. monocytogenes and C. albicans, ret~;ning full antimicrobial activity in all cases. It is possible that the stability of these compounds to protease degradation and to autoclaving is enhanced by the presence of disulfide bonds.
The protegrins were also tested for their ability to bind the lipid polysaccharide (LPS) of the Gram-negative bacterium ~. coli strain 0.55B5.
Both synthetic and native PG-l, PG-2 and PG-3 in the amidated and nonamidated forms are able to bind LPS at concentrations as low as 2.5 ~g/0.2 ml. nPG-l and nPG-2 are effective at somewhat lower concentrations. The protegrins were substantially more effective than the NP or HNP test compounds; the most effective among these controls was NP-3a, CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 a peptide whose primary sequence most closely resembles that of the protegrins.
Inhibition of gelation can be overcome by increasing the concentration of LPS, therefore interaction with LPS is responsible for the lack of gelation, rather than interfering with the gelation enzyme cascade.
nPG-1 and nPG-3 were converted to linear form using a reducing agent to convert the disulfide linkages to sulfhydryl groups, which were then stabilized by alkylating with iodoacetamide.
The linearalized forms of the protegrins are equal to cyclic forms in inhibiting gelation in the endotoxin assay and in binding to endotoxin.
Both linearalized and cyclic forms of the protegrins tested continue to show antimicrobial activity, although the effectiveness of these peptides as antimicrobials depends on the nature of the target organism and on the test conditions.
The antimicrobial activity of cyclic and linearalized PG-l and PG-3 in the concentration range 20 ~g/ml-125 ~g/ml with respect to E. co7i ML-35P was measured with and without 100 mM NaCl. The linear form was slightly more potent in the presence of buffer alone than was the cyclic form; on the other hand, the cyclic form was more potent than the linear form under isotonic conditions.
For L. monocytogenes, both cyclic and linearalized forms of the protegrins showed strong antimicrobial activity in the absence of salt and both were approximately e~ually effective over the concentration range tested (20 ~g/ml-125 ~g/ml).
The cyclic form retained strong antimicrobial activity in 100 mM NaCl with a slightly greater concentration dependence.
Linearalization appeared to lower the activity appreciably although high concentrations were still able to show an antimicrobial effect.
A11 forms of these protegrins were effective against C. albicans in a dose-dependent manner over the above concentration range when tested in the presence of 10 mM
phosphate buffer alone, although the linearalized peptides were very slightly less effective. While the cyclized forms CA 02238610 1998-0~-22 WO 97/18826 PCT/US96~8~44 retained approximately the same level of antimicrobial e~fect in 100 mM NaCl, the activity of the linearalized forms was greatly ~; ;n;~h~ so that at concentrations below 100 ~g/ml of the protegrin, virtually no antimicrobial effect was seen.
At higher concentrations of 130 ~g/ml, a moderate antimicrobial effect was observed.
Thus, depending on the target microorganism and the conditions used, both the cyclized and linearalized forms of the PG-1 and PG-3 have antimicrobial activity.
Contact lens solutions are typically formulated with borate buffered physiological saline and may or may not contain EDTA in addition. Protegrins in the form of the synthetic PG-3 amide and synthetic PG acid were tested wherein underlay gels contain 25 mM borate buffer, pH 7.4, 1%
(v/v) tryptocase soy broth (0.3 ~g/ml TSB powder) and 1%
agarose. Additions included either 100 mM NaCl, 1 mM EDTA or a combination thereof. Other test compounds used as controls were the defensin NP-1 and lysozyme. Dose response curves were dete ; ne~ .
Although these protegrins are somewhat less active in 25 mM borate buffered saline than in 25 mM phosphate buffer, the antimicro~ial activity is ~h~n~ by adding physiological saline and modestly enhanced by 1 mM EDTA.
Tests with C. albicans and with L. monocytogenes indicate that the protegrins are capable of exerting their antimicrobial effects under conditions typically associated with conditions suitable for eye care products.

Bxam~le 2: RecoverY of cDNA Clones As described in WO 95/03325 referenced above, cDNAs encoding PG-1, PG-2, PG-3 and PG-4 were prepared from porcine leukocytes and the DNA sequences encoding these protegrins are set forth in Figure 7 of the published application.

CA 02238610 1998-0~-22 Exam~le 3: Recovery of Genomic DNA Encoding PG-1 PG-3 and PG-5 High molecular weight genomic DNA was purified from pig white blood cells with the QIAGEN blood DNA kit (QIAGEN, Chatsworth, CA). To amplify protegrin (PG) genes, PCR as performed using genomic DNA as a template.
The sense primer (5J-GTCGGAATTCATGGAGAC~A~-AG(A or G)GCCAG-3') corresponded to the 5' regions of PG cDNAs, of Example 2 and provided an EcoRI restriction site. The anti-sense primer ~5'-GTCGTCTAGA~C or G)GTTTCAC~A~-AA~TTATTT-3') was complementary to 3' ends of PG cDNAs ; ?~;ately pr~c~;ng their poly(A) tails and provided an XbaI
restriction site. The reaction was carried out in a total volume of 50 ~1, which contained 200 ng of purified pig genomic DNA, 25 pmoles of each primer, 1 ~g of 10 mM dNTP, 5 ~g of 10X PCR buffer (200 m~ Tris-HCl, 100 mM(NH4)2, 20 mM
MgSO~, 1% Triton X-100, 0.1% BSA), and 2.5 units of cloned Pfu DNA polymerase (Stratagene, La Jolla, CA). Thirty cycles were performed, each with 1 min of denaturation at 94~C, 1 min of primer annealing at 55~C, 2 min of primer extension at 72~C, and a final extension step at 72~C for 10 min.
The amplified PCR product was digested with EcoRI and XbaI, excised from the agarose gel, purified, and ligated into pBluescript KS+ vector (Stratagene, La Jolla, CA) that had been digested with EcoRI and XbaI and purified. Both strands of DNA were sequenced by the dideoxy method using the Sequenase version 2.0 kit (United States Biochemical, Cleveland, OH), pBluescript universal primers and specific oligomer primers based on PG genomic and cDNA sequences.
Computer analysis of the DNA sequences was performed using the PC-Gene Program (Intelligenetics, Palo Alto, CA).
A PCR product of about 1.85 kb was confirmed as protegrin-re-ated by hybridization with a protegrin-specific oligonucleotide probe complementary to nt 403-429 of the protegrin cDNA seqll~nre~. The PCR product was then subcloned into pBluescript vector, and recombinant plasmids were subjected to DNA purification and sequencing. Gene sequences for three different protegrins were identified PG-~, PG-3 and CA 022386l0 l998-0~-22 WO 97/18826 PCT~US96~8544 PG-s. The nucleotide sequences and deduced amino acid se~uences are shown in Figure 1.
Comparison of protegrin cDNAs and genes revealed that the coding regions of protegrin genes consisted of four exons, interrupted by three introns (Figure 2). The first exon contained the 5' noncoding region and codons for the first 66 amino acids of the protegrin prepropeptide, including a 29 residue signal peptide and the first 37 cathelin residues. Exons II and III were relatively small, only 108 and 72 bp respectively, and together cont~;ne~ the next 60 cathelin residues. The final two cathelin residues were on Exon IV, and were followed by the protegrin sequences. The exon-intron splice site sequences are shown in Table 1, and conform to the consensus rule: all introns end on an AG doublet, preceded by a T/C rich stretch of 8-12 bases, while all introns start with GT, followed pred~ ;n~ntly by A/G A/G G sequence.

Table 1 Exon-Intron 8tru¢ture of the PG-1 Gene Exon Size 5' ~plice donor Intron Size 3' ~plice ~c~ o~
1?~198 AAGGCCgtgagtcg 1 405 tt~c~ ~r-~-2108 AACGGGgtgaggct 2 152 ccttccagCGGGTG
372 AATGAGgtgagtgg 3 596 ggtcacagGTTGAA

The highly conserved cathelin region spans exons I-IV
and ~xon IV contains the full sequence of the mature protegrin peptide followed by an amidation consensus sequence, a 3~ untranslated region, and the putative polyadenylation site. The three introns range in size from 152 to 596 bp. If the protegrin genes are representative of other cathelin-like genes, the third intron o~ cathelin-associated peptides will be found to separate all but the last two residues of the highly conserved cathelin region from the variable antimicrobial peptides encoded in Exon IV.
Such a layout would favor recombination m~rh~ni~m~ involving association of diverse Exon IVs with the first three exons specifying cathelin cont~ g prepro-regions.

CA 02238610 1998-0~-22 The family of naturally occurring protegrins thus contains at least 5 members. Figure 5 shows a comparison of the amino acid sequences of the five protegrins found so far in porcine leukocytes. There is complete homology in positions 1-3, 5-9, 13 and 15-16.
Homology search of protegrin genes against the EMBL/GenBank identified no significantly homologous genes.
More specifically, the gene structures and nucleotide se~uences of protegrins were very different from those of defensins, which contain three exons in myeloid defensin genes, and two exons in enteric defensin genes. As expected, the search yielded the large family of cDNAs corresponding to cathelin-associated bovine, porcine and rabbit leukocyte peptides.
To assess protegrin-related genes further, we screened a porcine genomic library of approximately 2.3 x 105 clones in EMBL-3 SP6/T7 with the 32P-labeled protegrin cDNA, and identified 45 hybridizing clones.
A porcine liver genomic library in EMBL3 SP6/T7 phages was purchased from Clontech (Palo Alto, CA). E. coli strain K803 was used as a host, and DNA from phage plaques was transferred onto nylon membranes (DuPont, Boston, MA). The filters were hybridized with 32P-labeled porcine 691 PG-3 cDNA. The filters were washed several times, finally at 60~C
in O.lx SSC and 0.1% SDS, and exposed to x-ray film with an intensifying screen at -70~C. Positive clones were subjected to two additional rounds of pla~ue purification at low density.
DNA purified from hybridizing clones was digested with various restriction endonucleases (New ~ngland Biolabs, Beverly, MA), fractionated on 0.8% agarose gels, and transferred onto GeneScreen Plus mem~rane (DuPont, Boston, MA). The hybridization probes were labeled with 32p and included porcine PG-3 cDNA, and 5~-labeled protegrin-specific oligonucleotide complementary to nt 403-429 of PG-l, 2 and 3 cDNAs. For the cDNA probe, the hybridization and washing conditions were carried out as for the library screening.

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18S44 For ~he oligonucleotide probe, the membranes were washed at 42~C in O.lx SSC, 0.1% SDS.
Southern blot analysis was carried out with purified DNA
from positive clones by hybridization with protegrin cDNA and a protegrin specific oligonucleotide complementary to nt 403-429 of protegrin cDNA sequences. Although all of the clones hybridized with the complete cDNA probe, on~y about half of them hybridized with the protegrin-specific probe. A
specific oligonucleotide probe for porcine prophen;n, another cathelin-associated porcine leukocyte-derived antimicrobial peptide, hybridized to several of the nonprotegrin clones.
These results confirm a) that the conserved proregion homologous to cathelin is present within the same gene as the mature antimicrobial peptides and is not added on by posttranscriptional events, and b) that the protegrins account for about half of the cathelin-related genes in the pig.
A synthetic peptide corresponding to the amino acid seguence of PG-5 was prepared and tested with respect to antimicrobial activity against E. coli, L. monocytogenes and c. albicans. The results were c ,-red to those obtained with a synthetically prepared PG-1. The results are shown in Figures 3a-3c. As shown in these graphical representations of the results, PG-~ has comparable antimicrobial activity to PG-1 against all three organisms tested.

ExamPle 4: PreParation of EnantioPG-1 Using st~n~rd solid phase t~hn i ~ues, a protegrin having the amino acid sequence of PG-l, but wherein every amino acid is in the D form was prepared. This form of protegrin was tested against E. Co 7 i, L. monocytogenes, C. al~lcans and other microbes in the absence and presence of protease and otherwise as described for the radiodiffusion assay in agarose gels, generally as described by Lehrer, R.I.
et al. J Immunol Met~ ~1991) 137:167-173. The results show that both native PG-1 and enantio PG-1 in the absence of protease are equally effective in inhibiting the growth of E. coli. Neither trypsin nor chymotrypsin inhibits the CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 antibacterial effect of enantio PG-1. In the presence of these proteolytic enzymes, the ability of native PG-1 to inhibit the growth of L. monocytogenes is adversely affected, although in the absence of these proteases PG-l is comparably active to an enantio PG-1.
Using similar techniques, the enantio forms of PG-2, PG-3, P~-4 and PG-5 are synthesized. Similarly, the enantio forms of the specific compounds set forth herein are prepared.

~xamPle 5: Activity of the Protegrins Against STD Pathoqens As reported in W0 95/03325, PG-1 was tested against a variety of organisms which are responsible for the infections associated with sexually transmitted diseases (STDs). PG-1 was highly active against HIV-1, Chlamydia trachomatis, Treponema pallidum, Neisseria gonorrhoeae, and was moderately active against Trlchomonas vagi n~ 7 i.c and Herpes simplex type 2. PG-1 appeared inactive against Herpes simplex type 1, however, another protegrin, the amide form of RGGLVYVRGRFCVCVGR, was active against Herpes Simplex virus type 1.

ExamPle 6: Antiretroviral ActivitY
Both synthetic and native PG-1 and native PG-2 showed antiviral activity against various strains of HIV using the method described in Miles, S.A. et al., Blood (1991) 78:3200-3208, as set forth in W0 95/03325.
The protegrins show similar activity with respect to other retroviruses.

E~amPle 7: Preparation of Modified Protegrins:
Kite and Bullet Forms The kite and bullet forms of PG-1 wherein all Z are ~l~n;ne were synthesized using conventional Fmoc chemistry.
The crude synthetic peptide was reduced by adding dithiothreitol (DTT) equal in weight to the synthetic peptide which had been dissolved at 10 mg peptide/ml in a solution cont~;n;ng 6 molar guanidine HCl, 0.5 molar tris buffer, and - ~2 -CA 02238610 1998-0~-22 WO 97/18826 PCT/US96/18~;44 2 mM EDTA, pH 8.05 and incubated for two hours at 52~C under nitrogen. The mixture was passed through a 0.45 ~m filter, acidified with 1/20 (v/v) glacial acetic acid and subjected to conventional RP-HPLC purification with a C-18 column.
HPLC-purified, reduced synthetic bullet and kite PG-l were partially concentrated by vacuum centrifugation in a speed vac and allowed to fold for 24 hours at room temperature in ambient air in o.l M Tris pH 7.7 at low concentration (0.1 mg peptide/ml) to minimize formation of interchain disulfide disulfides. The mixture was then concentrated and acidified with HOAC to a final concentration of 5% and subjected to RP-HPLC purification.
The purity of the final products bullet and kite PG-l was verified by AU-PAGE, analytical HPLC, and FAB-mass spec.
AU-PAGE showed a single band for the final product in each case. The observed MH+ mass values were z093 in both cases.

Exam~le 8: Antimicrobial Activity of the Kite and Bullet Forms The kite and bullet PG-l compounds prepared in Example 7 were tested for antimicrobial activity using the radial diffusion assay as published by Lehrer, R.I. et al ., J
T nol Meth (1991) 137:167-173, except that the underlay agars contained 10 mM sodium phosphate buffer with a final pH
of 7.4. As described in Example 1, 0.3 mg/ml ~rypticase soy broth powder and 1% agarose were used as well in the underlay agar. In some cases 100 mM NaCl or RPMI plus 2.5% normal human serum (NHS) was added to the agar.
In a first set of determinations, the bullet and kite forms of PG-l were tested for antimicrobial activity against L. monocytogenes, E. ~aecium (VR) or S. aureus under these three sets of conditions.
The bullet and kite forms were roughly e~ually effective against these three bacteria using st~n~rd assay conditions.
When 100 mM NaCl was added to the agar, however, the kite forms appeared slightly less active than the bullet forms which appear to have slightly ~h~nced antimicrobial activity against all three strains except S. aureus under these CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 conditions. Similarly, when RPMI plus 2.5% NHS were added, the bullet forms were again more effective than the kite forms. The activity of the kite form versus E. faecium was significantly less under these conditions.
These forms of PG-l were also tested against E. coli, R. pneumoniae and P. aeruginosa. All three microorgAn; ~mc were inhibited by both kite and bullet forms under standard conditions. This antimicrobial activity was maintained also at 100 mM NaCl and RPMI plus NHS.
ExamPle 9: SYnthesis of the Snake Form of PG-l The snake form of PG-l wherein all Z are Al~n;ne was performed using stAn~rd methods by Synpep Inc., Dublin, CA
and the MH+ value in FAB-mass spec was 2031.3 as expected.
The snake form was purified to homogeneity by RP-HPLC.

ExamPle 10: Antimicrobial Activity of Snake PG-l Snake PG-l was tested with respect to the same six orgAn; ~r~ and using the same conditions as set forth in Example 8 with respect to the bullet and kite forms of PG-l.
In this case, the native two-disulfide form of PG-l (native) was used as a control. While the snake form shows somewhat superior activity with respect to L. monocytogenes, E. faecium, and S. aureus under stAn~Ard conditions, it is notably less effective than the native form in the presence of either 100 mM NaCl or RPMI plus NHS. The same pattern is followed when the test orgA~ are E. coli, ~. ~n~t77noniae~
and P. aeruginosa.

ExamPle 11: Preparation of Miniprotegrins and Protegrins with Enhanced Basicitv A series of protegrins was prepared, including bullet and kite forms, wherein one or both of Xs and Xl6 is a basic as opposed to a hydrophobic amino acid and/or wherein Xl-X4 are absent. The peptides prepared are summarized and compared to the amino acid sequence of PG-l as shown in Table 2.

W O 9~18826 PCTAJS96/18544 Tnble 2 8eq~ns~R of 8elected M~nirrotegrinS
Code Sequence Ma~
PG-1RGGRLCYCRRR'~v~v~ 2154.04 PC-llLCYCRRR~v~v~K 1730.li PC-12RCY~KKK~V~ 1773.14 PC-13R~RTCY~K~R~v~v 1943.35 PC-14RGGRLCYCRRRFCICV 1957.38 PC-15RGGRL~Y~K~kr~v~K 2000.41 PC-16RCY~k~v~K 1616.96 PC-17LCY~KRX~v~v 1516.87 PC-18LCYARRRFAVCV 1454.77 PC-l9~ry~RR~AVCR 1554.85 PC-20~AY~Kk~VAV 1454.77 PC-21RAY~KKK~VAR 1554.85 PC-22RGGRLCY RR VCVGR* 1648.97 PC-31aGGRLCY~n~R~v~v~n 1999.40 PC-32aRGRL~Y~KKn ~v~v~ 2098.54 PC-33aGRL~r~nnk~'~v~v~K 1942.35 PC-34aRRLCYCRRR~v~v~K 2041.49 PC-35aRLCY~Knk~'~v~v~K 1885.30 PC-36ak~I~Khh~ ~V~V~K 1928.33 PC-37a ~Y~K~'~V~V~K 1615.95 PC-44a RGGRLCYCRRRFCVCR* 2000.41 PC-45RGGRLCY~nK~v~ 1843.22 PC-46R~RTCY~KKR~V~A 1844.22 PC-47a RGGRLCY RRRF VCVGR 1951.33 PC-48RGWRLCY~nRR~v~v~K 2284.75 The a~teri~k (*) in Table 2 indicate~ C-t~r~in~l free acid; all others are C-t~rm;n~l amide~.

The protegrin congeners were tested using the radial diffusion assay described above using mid-log phase organisms, except that assays with C. albicans used overnight cultures. As described above, all underlay agars contained 0.3 mg/ml trypticase soy broth powder/ml, 1% w/v agarose and 10 mM sodium phosphate buffer, pH 7.4 and were seeded with 4 x lo6 bacterial or fungal CFU/lOml. The st~n~Ard underlay agar, medium A, is as described; medium B is identical except that it also contains 100 mM NaCl; medium C contains the stAn~Ard medium plus 2.5% normal human serum; and medium D
contains 80% RPMI-1640 plus 2.5% normal human serum.

CA 022386l0 l998-05-22 The test peptides were dissolved at 500 ~g/ml in 0.01%
acetic acid and serial dilutions were prepared in the same solvent either as two-fold dilutions or half-log dilutions (half-log dilutions are, from 500 ~g/ml, 250, 78, 25, 7.8, 2.5, 0.78, 0.25 and 0.078 ~g/ml).
The dilutions were made daily in sufficient amount for that day's experiments; to perform the tests, 5 ~g volumes of the solutions were added to prepunched wells ~3 mm diameter) in the bacterial underlay gels. Overlay gels (2 X
conventional trypticase soy agar) were poured after 3 hours.
Zone sizes were measured to the nearest 0.~ mm after overnight incubation. Zone sizes in units of clearing (10 units = 1 mm diameter) were graphed against logl0 of the peptide concentration using the sigma plot program. The X-intercept corresponds to the ' n; ~1 microbicidal concentration and was deteL ; ne~ by least mean squares regression analysis. Only the highest peptide concentration which showed no clearing was included in the calculation.
The results are provided both in terms o~ ; n; ~1 microbicidal concentrations in ~Lg/ml and relative molar potency, which corrects for molecular weight.
In the initial experiments, PC-11 and PC-12 were tested in co ~riSon to PG-1. The results are shown in Tables 3 and 4.
Table 3 Minimal Microbicidal Concentrations (~g/ml) 5Ori~s 1 10 mM Pho~ph~t~ Buff-r 10 mM Buff~r 1 100 mM N~Cl D~lutlonn Org~ni~ Prot~grin PC-ll PC-12 Prot~grin PC-ll PC-12 pa-l PG-l E. col~ ML-35p 5.3 2.3 3.8 2.8 1.3 1.9 . mono., ~CD 5.8 4.8 5.1 3.6 3.7 5.5 C. ~lo~c~nJ 820 6.1 7.1 4.3 7.9 11.6 20.5 S. ~ureu~ 930918-37.0i0.54 3.7 3.3 4.5~0.26 3.3 3.9 MRSA 30371n.t.n.~.n.t. 4.0~0.18 3.2 3.1 MRSA 28841 n.t. n.t. n.t.3.110.03 2.1 2.6 Table 4 Relative Molar Potency (PG-1 = 1.00) As shown in Table 4, the shortened forms of the protegrins are slightly more effective against E. Coli and against S. aureus as compared to PG-1 and comparably effective against the remaining organisms tested except for C. albicans where the effectiveness was of the same order of mangitude.
Tables 5 and 6 show the minimal microbicidal concentrations and relative molar potency of an embodiment, PC-15, where X16 is a basic amino acid. PC-13, shown in these tables, is identical to PG-1 except that it lacks X17 and X18.
As shown in these tables, replacing X16 with a basic amino acid generally enhances the potency against most organisms, but alters the response to the addition of salt.

Table 5 Minimal Microbicidal Concentrations (µg/ml) Table 5 Minimal Microbicidal Concentrations (µg/ml) Table 6 Relative Molar Potency PG-1 = 1.00) Tables 7-10 show results for PC-16 and PC-17, both of which lack X1-X4; PC-16 also contains basic amino acids at positions X5 and X16. Tables 8 and 10 relate to minimal microbicidal concentrations and differ only in that the dilution method has been altered. In Tables 8 and 9 two-fold dilutions were used and in Tables 10-11 half-log dilutions were used. The data in these tables show that the effectiveness compared to PG-1 varies with the target organism and with the conditions of testing. As shown in Table 9, for example, PC-17 (and PC-16) are mostly comparatively less active than PG-1 in the presence of salt;
as shown in Table 11 the presence of serum is also problematic, especially for PC-16.

Table 7 Minimal Microbicidal Concentrations (µg/ml) Table 8 Relative Molar Potency (PG-1 = 1.00) CA 022386l0 l998-0~-22 Tnble 9 ~~~n; -1 Micro~c;~l Concentrations (~g/ml) Series 2 Buffer + 100 mM NaCl RP~I ~ 2.5~ N~S
Dilutions Organi~m PG-1PC-16 PC-17 PG-1 PC-16 PC-17 E. coli ML-35p 1.40.59* 1.00.36 0.49 0.42 L. mono., EGD 0.7 1.5 0.70.35 0.61 0.42 C. albicans 820 8.6 25.510.5 7.1 24.1* 29.8*
E. faecium 1.210.0 0.630.42 31.1 0.40 VREF, CDC21 1.511.3 1.6 0.5 28.4 0.90 (E. faecalisJ
VREF, 94.132 0.670.44 0.560.37 8.8 0.39 (E. faecium) P. aeruginosa 1.30.41 1.20.96 8.8 0.80 ~5 MR 2330 P. aeruginosa 1.4 1.2 l.l0.81 2.8 0.83 SBI-N
P. aeruginosa 1.30.80 0.60 1.1 8.9 0.88 P. a~ruginosa 1.40.85 0.590.91 3.9 0.81 S. aureus3.3 ~250 3.9 0.440.82* 0.35 MRSA 30371 1.5~250 1.60.32 1.0* 0.30 MRSA 28841 1.37.9* 1.6 0.6 9.5 0.20 Tablo 10 Relative Molar Potency (PG-1 = 1.00) Series 2 Dilutions Buffer + lOO mM RPMI ~ 2.5% N~S
NaCl organi~m PC-16PC-17 PC-16 PC-17 ~. coli ML-35p 1.780.99 0.35 0.60 L. mono., EGD 0.350.70 0.43 0.59 C. albicans 820 0.250.58 0.22 0.17 E. faecium 0.091. 34 0.01 0.74 VREF, CDC21 O.100.66 0.01 0.39 (~. faecali~) VREF, 94.132 1.140.84 0.03 0.67 (E. faecium) P. aeruginosa MR 23302.38 0.76 0.08 0.85 P. aeruginosa SBI-N 0.88 O.90 0.22 0.69 P. aeruginos~ MR 30071.22 1.53 0.09 0.88 P. aeruginosa MR 21331.24 1.67 0.18 0.79 s. aureus 930918-3<0.03 0.60 0.40 0.89 MRSA 30371 <0.030.66 0.24 0.75 MRSA 28841 0.120.57 0.05 2.11 WO 97/18826 PCT~US96/18544 Tables 11-14 show the results ~or the kite forms of the invention protegrins. Again, it is apparent that the spectrum of target org~n;~;m~: which are responsive and the spectrum of conditions under which response is obtained are~ 5 variable. In general, the more cationic form, PC-l9 is less ef~ective than the unmodified form which merely lacks the residues Xl-X4. Under physiological conditions, PC-l9 is substantially inactive.
Table 11 M;n; -1 Microbicidal Concentr~tions (,ug/ml) 8eries 1 10 mM Pho~phate Buffer Buffer + 100 ~M NaCl Dilution~
organism Pa-1 PC-18 PC-l9 PG-l PC-18 PC-l9 E. faecium7.7 1.7 17.7 4.2 2.9 >250 VREF, CDC21 n.t. n.t. n.t. 4.6 5.3 >250 (E. faecalis) V~EF 94.132 n.t. n.t. n.t. 3.6 1.4 5.6 (E. faecium) S. aureus 7.3 3.9 7.3 5.0 2.1 10.4 MRSA 30371n.t. n.t. n.t. 4.1 6.5 68.6 MRSA 28841n.t. n.t. n.t. 3.6 3.9 17.4 Table 12 Relative Molar Potency (PG-l - 1.00) Series 1 Dilutions 10 Mm Phosphate Buff~r + 100 mM NaCl Buffer Or~anism PC-18 PC-l9 PC-18 PC-l9 E. faecium 3.06 0.31 0.98 0.01 VREF, CDC21 n.t. n.t. 0.59 0.01 (E. faecalis) VREF 94.132 n.t. n.t. 1.74 0.46 (E. faecium) S. aureus 930918-3 1.26 0.72 1.61 0.35 MRSA 30371 n.t. n.t. 0.43 0.04 MRSA 28841 n.t. n.t. 0.62 0.15 CA 022386l0 l998-05-22 W O 97/18826 PCTrUS96tl8544 Table 13 Minimal Microbicidal Concentrations (~g/ml) S~ries 2 10 mM Buffer ~ 100 ~M RPMI + 2.5% N~S
Dilution~ NaCl Organ sm PG-l PC-lB PC-19 Pa - 1PC-18 PC-l9 E. faecium1. 5 3.2 ~250 2.9 >250 VREF, CDC21 1.4 3.4 >250 10.0 >250 (E. faecalis) VREF 94.132 0.61 0.50 2.9 0.30 1.2 30.2 (E. faecium) P. aeruginosa 1.3 1.1 3.0 0.7 3.0 29.2 P. aeru~ino~a 1.3 1.2 2.1 0.85 4.6 ~250 SBI-N
P. aeru~inosa 1.3 1.1 1.1 0.72 3.89 ~250 P. aeruginosa 1. 2 2.4 2.5 O.9 3.9 ~250 Table 14 Relative ~olar Potency ~PG-1 - 1.00~
S~rios 2 Dilutions l0 mM Buff~r + l00 m~ RPMI + 2.5~ N~S
NaCl Orgnnism PC-18 PC-19 PC-18 PC-l9 E. faecium 0.32 <0.01 0.98 0.01 VREF, CDC21 ~E. faecalis) 0.28 <O.Ol0.03 <0.01 VREF 94.132 (E. faecium) O .81 0.15 0.17 <0.01 P. aeruginosa MR 2330 0.8 0.31 0~16 0.02 P. aeruginosa SBI-N 0.73 0.45 0.12 <0.01 P. aeruginosa MR 30070.80 O.85 0.13 <0.01 P. aeruginosa MR 21330.34 0.35 0.16 <0.01 Tables 15 and 16 provide results obtained with the l~ite forms of the invention protegrins. The more cationic forms are generally less effective than PG-1 under conditions of high salt or serum. However, they are comparably effective against E. coli.

WO 97/18826 PCT~US96~8544 Table 15 Minimal Microbicidal Concentrations (~g/ml) S-ri~n 110 mM Pho~ph~t~ 8u~~~r 1 100 mM N~Cl B~f~er + 2.5% NH8 Dilut~on~ Buff~r Org~n~m PG-lPC-20 PC-21PG-l PC-20PC-21 PG-l PC-20 PC-21 B. coli ML-35 4.6 0.750.36 2.0 1.9 1.8 0.34 0.27 0.28 L. mono. EGD 4.8 3.31.4 3.421.736.3 1.3 5.5 5.6 C. albica~ 6.1 5.3 8.56.8 67.5~250 8.1 30.1 59.7 E. faecium 6.7 6.7 18.03.9 69.0,250 VREF CDC21n.t.n.t. n.t.4.9 ~250~250 (faécali~) VREF 94.132n.t.n.t.n.t.2.5 3.328.3 (faecium~
S. aureus 10.3 5.8 7.25.1 30.36~.6 93~918-3 MRSA 30371n.t.n.t. n.t.4.2 29.964.6 MRSA 28841n.t.n.t. n.t.3.3 8.4 8.4 Table 16 Rclative Molar Poten¢y (PG-1 = 1.00)

8-r~s 1 D~lutlon~ 10 ~M Pho~ph~t~ Bu~f~r + 100 ~ Bu~f-r t 2.5%
Buff~r ~aCl N~S
Org~ni~P~-20PC-21 PC-20 PC-21PC-20PC-21 E. coli ML-354.149.21 0.71 0.84.500.88 L. mo~o. EGD0.982.47 0.09 0.070.160.17 C. albican~ 8200.78 0.52 0.07c0.020.18 0.10 E. faeci~m 0.680.27 0.03 0.01 VREF, CDC21n.t.n.t. 0.01 0.01 (f~ 7J~) VREF 94.132n.t.n.t. 0.20 0.06 (~aecium) S. aureus 930918-3 1.20 1.030.11~0.06 MRSA 30371 n.t.n.t. 0.09 <0.05 MRSA 28841 n.t.n.t. 0.26 0.28 Exam~le 12: Minimal Bioactive Conformation of PG-1 Necessary for Activity Against Neisseria gonorrhoeae The susceptibility of N. gonorrhoeae to variants of protegrin PG-l was determined using the radial diffusion assay of Lehrer et al., 1991, ~ Immunol Nethods 137:167.
Native protegrin PG-1 was purified for porcine leukocytes by the method of Kokryakov, V.N. et al. (FEBS Lett (1993) 327:231-236). All other protegrins were prepared WO 97/188Z6 PCT~US96/18544 synthetically with F-moc chemistry and purified by reverse phase HPLC.
The following N. gonorr~oeae strains were tested: FA19 (sac-l, sac-3; serum-resistant [SacR;), JS-1 (serum-resistant;
sac-1, sac-3; [sacR]) / and F62 (sac-1~, sac-3; serum-sensitive tsacS]) have been described by Cannon et al. (Infect Immun (1981) 32:547-552)and Judd, R.C. (Infect Immun (1982) 37:632-641). Strains FA628 (sac-1~, sac-3) and FA899 (sac-7, sac-3+) are SacS transformants of FAl9 (Shafer, W.M. et al., In~ect Immun (1982) 35:764-769). Strains FA5101 and WS1 are pycin-resistant mutants of strain FA19 that produce a truncated ~OS
(Lucas, C.E. et al., Molec Nicrobiol (1995) 16:1001-lO09).
Bacteria were streaked on NGTM medium, incubated overnight at 37~C in 5% C02/room air and passaged daily. Bacteria from plates were placed in 25 ml GC broth and incubated at 37~C
with sh~k;ng for 3 hours to obtain mid-log gonococci.
Underlay and overlay gels were prepared as previously described for the radial diffusion assay of Qu, X.D. et al.
Peptides were dissolved and serially diluted in 0.01% acetic acid and 5 ml aliquots were tested. Plates were incubated in a co2 incubator at 37~C for 3 hours before pouring the overlay gel, to allow peptides to diffuse into the underlays. After overnight incubation, the minimal inhibitory concentrations (mg/ml) were determined from the X-intercepts of the curves as described by Qu et al. Each strain showed protegrin-sensitivity (Tables 17-19).

CA 022386l0 1998-05-22 WO 97118826 PCT~US96tl8544 Table 17 Activity Against Neisseria gonorrhoeae ami~o M~ 1 Inh~b~tory Conc~tratlon acidll (I g/~nl) Protcgrin S~, ~n~ n P62 ~8-1 FA19 PG-1 RGGRLCYCRRRF~vCv~K 18 1.3+0.1 1.2~0.1 1.9+0.1 PC-13 RGGRLCYCRRRFCVCV-- ~6 0.6~0.2 1.4+0.04 2.3+0.8 PC-11 ----~CYCRRRF~v~v~K1~ 1.0+0.11.6+0.3 2.8+0.1 PC-17 ----LCYCRRRFCVCV-- 1~ 0.6_0.11.3+0.2 1.7+0.1 PC-37 -----CYCRRRF~v~v~ 13 4.2il.11.8+0.2 10.7+0.5 PC-45 RGGRLCYCRRRFCVC--- 15 1.1+0.3 2.9+0.03 7.6i2.1 PC-71 -----CYCRRRFCVCV-- 11 4.5+0.84.7+1.0 16.1+0.9 PC-72 ----LCYCRRRFCVC--- 11 2.7+0.22.3+0.8 12.8+0.0 PC-73 -----CYCRRRFCVC---1029.8il.5 48.3+22.5 104.4+7.4 PC-8 R~r~T~AY~ ~AVAVGR 18 21.4+5.8 46.0+7.0 431+13 PC-9 ~-GRT~YCRRRFCVAVGR 18 1.0+0.3 1.1+0.2 7.3+2.3 PC-10 RGGRLCYARRRFAVCVGR 18 0.7+0.1 0.8+0.1 1.6+0.O
PC-18 ----LCYARRRFAVCV-- 12 0.7+0.1 2.1~0.4 8.3+2.0 PC-64 ----LCYTRRRFTVCV-- 12 0~7i0-1 1.4$0.2 4.5+0.3 PC-20 ----LAYCRRRFCVAV-- 12 1.1+0.2 8.5+2.5 32.4~5.7 PC-64a ----LTYCRRRFCVTV-- 12 0.7+0.1 0.7+0.1 2.1_0.1 All of the peptides in the table are the C-terminal amides.
Protegrins PC-13, PC-11 and PC-17 demonstrate that amino acid residues X1 through X4 and Xl7 through X18 may be deleted from PG-1 without a loss of inhibitory activity (Table 17).
The effect of the two intramolecular disulfide bonds of PG-1 on inhibition of N. gonorrhoeae was determined.
Elimination of both disulfide bonds (protegrin PC-8) reduces the inhibitory effect on all strains tested (Table 17). In contrast, protegrin PC-10, which lacks the CYs8 Cysl3 disulfide bond has increased activity against strains F62, JS-1 and FAl9. A variant of PG-1 lacking the CyS6 Cysl5 disulfide bond (PC-9) retains full activity against strains F62 and JS-l and shows a 3.8-fold reduction of activity against strain FA1~. Truncated 12-mer variants of PG-l having a single disulfide bond also show potent inhibitory activity (see protegrins PC-18, PC-64, PC-20 and PC-64a in Table 18).
The inhibitory activity of protegrin variants was also determined for two serum-sensitive strains, FA628 (sac-l+) and W O 97/18826 PCT~US96/18544 ~A89s (sac-3~), which were derived for ~he serum resistant FA19 strain. PG-1 showed similar activity against the wild-type, serum resistant FA19 strain and the serum-sensitive derivative strains FA628 and FA899 ~Table 18). Serum-sensitive strains were two to four fold more susceptible toPC-8 than was the serum-resistant strain. Variants PC-9 and PC-10, which have one disulfide bond, retain strong inhibitory activity.

Table 18 ~fQct of Protegrin~ Against 5e~ S~iti~ N. go~orrhoe~e strain amino acids ~in; 1 Inhibitory Concentration (~/ml) Protegrin n FAl9 FA62R FA899 PG-l 18 2.1+0.1 1.6~0.11.6+0.1 PC-8 18420.8+24.2150.9il4.0 263.5+10.3 PC-9 1811.2+1.8 4.0+0.13.9-~0.2 PC-10 18 1.7+0.1 1.2+0.11.3+0.1 Because LOS truncation increases suscepti~ility of gonococci to antimicrobial proteins of human PMN (Shafer, W.M. et al., 1986, J Infect Dis 86:910-917), protegrins PG-1, PC-8, PC-9 and PC-10 were tested against LOS mutants FA5101, WSl and wild-type strain FA19 (Table l9). LOS truncation resulted in increased susceptibility of N. gonorrhoeae to the linearized protegrin PC-8, but had little effect on susceptibility to PG-l or PC-10.

Table 19 Ef~ect of Protegrins Against N. go~orrhoeae ~05 Mutant~
amino ~cidfi ~~'~i -1 Inhibitory C~nc_~Lldtion (~g/ml) Protegrin n FAI9 FAS101 WSl PG-l 18 2.1~0.1 1.5+0.21.4~0.2 PC-8 18420.8+24.223.1+9.329.7il2.8 3~i Pc-s 1811.2+1.8 2.7+0.42.6~:0.7 PC-10 18 1.7+0.1 1.2+0.11.1+0.1 ExamPle 13: Electron Microscopy of N. gonorrhoeae treated with Proteqrins The effect of treatment of N. gonorrhoeae with 50 ~g/ml PG-1 or the truncated derivative PC-17 was determined.

W O 97/18826 PCTAUS9~8544 Transmission electron microscopy of bacteria after 60 minutes treatment with PG-1 reveals central vacuolation and membrane-associated, electron-dense structures. S~nn; ng electron microscopy of bacteria treated with PG-1 or PC-17 revealed surface lesions approximately 100 nm in diameter.

~ple 14: Effect of Saliva on Antimicrobial Activitv The radial diffusion assay of Lehrer et al., 1991, J.
Immunol. Meth. 137:167 was used, except that the media in the underlay agar contained phosphate buffer at 10 mM, pH6.5, 100 mM NaCl, 1% TSB, 1% agarose. The media in the overlay contain lo mM phosphate buffer, pH 6.5, 100 mM NaClr 2XTSB, 1% agarose. The peptides were diluted from lOX stock made up in 0.01% acetic acid (AA) either with 10 mM acetate buffer pH5 or with saliva.
The results are given as the m;~; ~l concentration required to produce a detectable zone of clearance, or MCZ --i.e., an extrapolated value to the x-axis when the concentration of peptide is plotted against the diameter of the zone. The results are shown in Table 20.
Ta~le 20 Effe¢t of Diluent on MCZ (~g/mL) again~t E. coli 004 8eguonce Acet~te S~llva bu~r RGGRLCYCRRRFCVCVGR O. 48 1.14 RGGGLCYARGWIAFCVGR 4.16 38.30 RGGGLCYKR~lK~v~ 2.71 0.56 RGWGLCYCRPRFCVCVGR 0.39 12.60 RGGRLCYCRRRFCVCVGR~ O. 59 1.45 LCYCRRRFCVCF 4.14 6.11 RLCYCRPRFCVCV 3.36 6.83 L~Y~K~V~V~K 2.37 5.68 RLCYCRPRFCVCVGR 1. 60 6.86 RWRLCYCRPRFCVCV 1.04 39.00 RGWRACYCRPRFCACVGR 0. 71 1.84 3~ GWRLCYCRPRFCVCVGR 0.86 47.50 ~L~r~ CVCV 13.70 9.76 WLCYCRRRFCVCV~ 5.05 36.00 RL~r~a~F~V~V (X=MeGly) 2.43 2.54 RLCYCRPRFCVCVGR~ 3.65 12.80 RGGGLCYCRPRFCVCVGR~ 3.51 11.90 CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 Table 20 Effect of Diluent on MCZ (,~g/mI,) against E. eoli 004 8~ ~ Ac--t~t~ 9a~ iva bu f f -r RRCYCRRRFCvCVGR 3.02 8.07 Peptides noted with ~ are acid forms; all others are amide forms~
A large number of the peptides tested showed c ~ -rable or even improved activity in the presence of saliva.

ExamPle 15: Antimicro~ial Activity of Additional Proteqrins lo The following example provides assays for measuring the antimicrobial activity that were used to test additional peptides of the invention described hereinbelow. The following reagents, stock solutions and cultures are used in the assays that follow.
Microorqanisms: l~:seherichia eoli ML-35p and vancomycin-resistant Enteroeoeeus faeeium (VRE) were obtained from Dr.
Robert Lehrer (UCLA, see also, Lehrer et al., 1988, J.
Immunol. Methods 108:153) and Dr. Gary Schoolnik (Stanford), respectively. Pseudomonas aeruginosa (ATCC 9027), Candida albicans (ATCC 1023), and methicillin resistant Staphyloeoecus aureus (ATCC 33591) were obtained from the American Type Culture Collection, Rockville, MD.
Microorganisms from other sources, such as, ~or example, clinical isolates, can be used interchangeably with the above-described microorganisms in the assays described herein.

Media and Reaqents:
TrYPticase SoY Aqar (TSA; Becton-Dickinson, Cockeysville, MD, BBL #4311768): dissolve 40 g in 1 Liter deionized water, autoclave 121~C, 20 minutes.
TrYPticase SoY Broth (TSB; Becton-Dickinson, Cockeysville, MD, BBL #4311768): dissolve 30 g in 1 Liter deionized water, autoclave 121~C, 20 minutes, and store at room temperature.

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 2X TrY~ticase Soy Broth (2X TSB): dissolve 60 g in 1 Liter deionized water, autoclave 121~C, 20 minutes, and store at room temperature.
Glycerol (20% v/v): mix 20 mL glycerol with 80 mL
deionized water, Filter sterilize with 0.20 ~ filter and store at room temperature.
Monobasic ~hosPhate buffer (100 mM): dissolve 13.7 g sodium phosphate monobasic ~Fisher #S368-500) in 1 Liter deionized water. Filter sterilize with 0.20 ~ filter and store at room temperature.
Dibasic Phosphate buffer (100 mM): dissolve 14.2 g sodium phosphate dibasic (Fisher #S374-500~ in 1 Liter deionized water. Filter sterilize with 0.45 ~ filter and store at room temperature.
Phos~hate-buffered saline (PBS; 10 mM phosphate, 100 mM NaCl, pH 7.4): mix 15 mL dibasic phosphate bu~fer (100 mM~, 5 mL monobasic phosphate buffer (100 mM), 4 mL NaCl (5 M~ and 176 mL deionized water. Adjust pH if necessary, filter sterilize with 0.45 ~ filter and store at room temperature.
Phos~hate buffer (100 mM, pH 6.5): mix 40 mL
dibasic phosphate buffer (100 mM~ with 160 mL monobasic phosphate buffer (100 mM). Adjust pH if necessary, filter sterilize with 0.45 ~ filter and store at room temperature.
Liauid Testinq Medium (LTM~: aseptically combine the following sterile ingredients: 10 mL Phosphate buffer (100 mM, pH 6.5~, 1.0 mL TSB, 2 mL NaCl (5 M~ and 87 mL
deionized water. Store at room temperature.
Acetic acid (0.01~ v/v): mix 10 ~L acetic acid with 100 mL sterile deionized water.
Aqarose: mix l g agarose (Sigma #S6013) in 80 mL
deionized water, autoclave 121~C, 20 minutes.
Aqarose Underlay Medium: combine 10 mL Phosphate buffer (100 mM, pH 6.5), 1.0 mL TSB, 2 mL NaCl ~5 M) and 7 mL
deionized water with 80 mL tempered (50OC) agarose.
2X TSB Aqarose Overla~ Medium: dissolve 60 g TSB
- and 10 g agarose in 1 Liter deionized water, aliguot 100 mL

W O 97/18826 PCT~US96/18544 per bottle, autoclave 121~C, 20 minutes, and store at room temperature.

Pre~aration of Microorqanism Slants: Each strain was cultured on TSA. Isolated colonies were transferred into ~SB
(10 mL in a sterile 50 mL Erlenmeyer flask) using a sterile, disposable loop and the flask ;n~llh~ted at 37~C (bacteria) or 30~C (yeast) with shaking (200 RPM) for 16-18 hours.
Broth cultures were diluted 1:1 with 20% sterile glycerol and stored as 1.0 mL aliquots at -80~C. For daily inocula, liquid was transferred from a thawed vial using a sterile loop and then spread onto the surface of TSA slants.
The screw capped tubes were incubated overnight and stored at 4OC for up to one month.
PreParation o~ Inoculum:
1. Remove the cap from tube and lightly touch a sterile loop to the area of heavy growth on the TSA slant.
2. Inoculate 10 mL of TSB (50 mL flask) and incubate the flask in a sh~k; ng water bath for 18 hours (overnight) at 37~C (bacteria) or 30OC (yeast) at 200 RPM.
3. In a cuvette, dilute 50 ~L of the overnight culture 1:20 with TSB and measure the absorbance at 600nm (A600) using TSB as a reference. The A6~0 of the diluted culture should be between 0.1-0.4.
4. In a 250 mL Erlenmeyer flask, dilute 50~L of the overnight culture 1:1000 with TSB (bacteria) or 1:100 with TSB (yeast).
5. Incubate the flask in a shaking water bath at 37~C (bacteria) or 30~C (yeast) at 200 RPM for approximately 2-3 hours until log-phase is reached, i.e. until the A600 of the culture is between 0.200 and 0.400 without further dilution.
6. Transfer 25 mL of the log-phase culture to a sterile centrifuge tube and centrifuge at 2000 rpm and 4~C
for 10 minutes. Decant the supernatant, add 25 mL of sterile PBS and resuspend the pellet by vortexing.

CA 022386l0 l998-05-22 W O 97/18826 PCT~US96/18544 7. Centrifuge the suspension at 2000 rpm and 4~C
for 10 minutes. Decant the supernatant and resuspend the pellet with 5 ml sterile PBS.
8. Measure the A600 of the undiluted suspension.~ 5 If the absorbance is above 0.5, dilute with sterile PBS until the absorbance is between 0.100 and 0.500.

9. Determine the number colony-forming units per milliliter suspension (CFUs/mL) by preparing 10-fold serial dilutions in saline (0.87%) and spre~cl;ng 100 ,uL of the 104-, 105-, and 105-fold dilutions onto TSA plates, one dilution per plate. Incubate overnight, count the number of colonies and determine the CFUs/mL (an accurate determination requires approximately 30-300 colonies per plate).

For the strains reported, the CFUs/mL for a suspension having an A6~o=0.2 have been determined as reported in the table below:
CFUs/mL of Suspension (~oo=0.2) 8train CFUs/mh E. coli 8.0 X 107 P. aeruginosa 7 . 8 x 107 MRSA 2.0 x 107 VRE 3.8 x 107 C. albicans 9 . 7 x 105 PreParation of PePtide Stock Solutions:
1. Weigh approximately 1.0 mg of each peptide to be tested into a sterile polypropylene cryovial (1.8 mL).
2. Add sufficient acetic acid (0.01%) to make a stock solution having a concentration of 1280 ~g/mL.
Dispense the stock solution into several vials, lO0 ~L per vial, and store the aliquots, tightly sealed, at -80~C.

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 6.5 Radial Diffusion fMCZ~ Assav The MCZ assay uses ;n; ~1 amounts of test materials to determine the sensitivity of microorganisms to various antimicrobial compounds. Cells are grown to approximately mid-log phase and resuspended in ;n; ~1 nutrient buffered agarose. Agarose (not agar) is used in this gel to avoid electrostatic interactions between antimicrobial peptides and the polyanionic components of st~n~Ard agar. Peptides diffuse r~ y into the gels from small wells and the diameter of the zone of growth inhi~ition is proportional to the concentration of peptide in the solution (Lehrer et al., 1988, J. Immunol. Methods 108:153;
Lehrer et al., 1991, ~. Immunol. Methods 137:167).

PreParation of MCZ AssaY Plates:
1. For each petri plate to be poured, dispense 10 mL of tempered (50OC) Agarose Underlay Medium into a sterile polypropylene tube (15 mL). Add 4x105 CFUs of the desired strain to each tube. Mix well by inverting tube 3 times.
Immediately pour the molten agarose into the petri dishes.
2. After the agarose has solidified, use a sterile canula (3 mm i.d.) to punch 16 wells (4x4 evenly spaced grid) into the agarose. Remove the agarose plugs with a pasteur pipette and trap the agarose in a flas~ with a side arm port attached to a vacuum.
3. From the peptide stock solution, prepare serial 2-fold dilutions (from 128 ~g/mL to 0.06 ~g/mL) using acetic acid (0.01%) as a diluent, or, for peptide concentrations lower than 50 ~g/mL, sodium acetate (10 mM, pH 5~ cont~;ning Human Serum Albumin (HSA; 0.1% w/v) as a diluent.
4. Dispense 5 ~L of each serial dilution into the agarose wells, one serial dilution per well.
5. Dispense diluents into wells as negative controls and protegrin-l (U.S. Patent No. 5,464,823; 32 ~g/mL, 8 ~g/mL and 2 ~g/mL) into wells as positive controls.
6. Incubate the plates at 37~C (bacteria) or 30~C
(yeast) for 3 hours.

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 ~. ~ispense 2X TSB Agarose Overlay Medium (10 mL) onto the surface of each plate, allow the agar to solidify and incubate plates, inverted, at 37~C (bacteria) or 30~C
(yeast) for 16-18 hours.
8. ~ ;ne the plates and measure (in mm) the diameter of the zone of growth inhibition (area of clearing around each well).
9. Plot the diameter of the zone of growth inhibition (Y-axis) versus the concentration of peptide in the well (X-axis) and obtain the line of best fit using l;ne~r regression analysis. The X-intercept of the line of best fit is the ;ni concentration for zone of growth inhibition (MCZ) for each peptide concentration.

6.6 Microbroth Dilution (MCB) AssaY
The microbroth dilution method accomodates large l~l h~rs of samples and is more amenable to automation than the MCZ assay and the data analysis is direct and simple. A
key step in this assay is combining microorg~n; ~m~ and peptide in a defined ;n; ~l nutrient buf~er system that ;n; ;zes interference with the peptide's biological activity. Tn addition, the presence of 0.1% (w/v) human serum albumin (HSA) or bovine serum albumin (BSA) to the peptide diluent ; n; ; zes adsorption of peptide to the container.

Pre~aration of MCB assav Plates:
1. Dispense 100 ~L of log-phase cells in LTM
(MCB-5 is 4x105 CFUs/mL; MCB-3 is 4x103 CFUs/mL) into each well of a sterile 96-well microtiter plate.
2. From the peptide stock solution, prepare serial two-fold dilutions (from 1280 ~g/mL to 0.625 ~g/mL) using acetic acid (0.01%) as a diluent, or, for peptide concentrations lower than 50 ~g/mL, sodium acetate (10 mM, pH 5) cont~;n;ng HSA or BSA (0.1%w/v) as a diluent.
3. Dispense triplicate ali~uots (ll ~L) of each ~ serial two-fold dilution into the wells of the microtiter plate.

CA 02238610 1998-0~-22 W O 97/18826 PCT~US96/18544 4. Incubate the plate at 37~C (bacteria) or 30~C
(yeast) for 3 hours.
5. Add 100 ~L of 2X TSB to each well, mix, and incubate at 37~C (bacteria) or 30~C (yeast) for an additional 16-18 hours.
6. F.5r~ ;ne the plates and evaluate each well for turbidity (cell growth). Often, MRSA will settle out and form a pellet at the bottom of the well. MRSA can be evaluated by placing the microtiter plate on a stand and e~A ;ning the bottom of the well using a tilted mirror.
7. The minimum concentration for inhibition of growth in broth medium (MCB) is defined as the lowest conc~ntration of peptide that inhibits all visible growth.
If the MCB values for each of the triplicate samples differ, the MCB is obtained by averaging the results of the three samples.
8. The minimum concentration of peptide showing at least 99.9% biocidal activity (at least a 3 log decrease from starting inoculum) is determined by incubating a 50 ~L
aliquot from each well on a TSA plate for 24 hours at 37~C
(bacteria) or 30~c (yeast) (for plating, 1.5 mL TSA in each well of a 24-well plate minimizes cross contamination).

6.7 Modified NCCLS Mirl; Inhibitory Concentration (MIC) AssaY
The National Committee for Clinical StA~rds (NCCLS) requires that test compounds be prepared as stock solutions in Mueller-Hinton Broth ("MH~") at 512 ~gtmL. The stock solutions are serially diluted (two-fold) in medium and each serial dilution added 1:1 to medium cont~in;ng lx106 CFU/mL bacteria (National Committee on Clinical Laboratory Standards, December 19g4, "Performance Standards for Antimicrobial Susceptibility Testing," NCCLS Document M100-S5 Vol. 14, No. 16; Methods for Dilution Antimicrobial SuscePtibility Test for Bacteria that Grow AerobicallYl 3d Ed., Approved Standard M7-A3, National Committee for Clinical Standards, Villanova, PA).

CA 02238610 1998-0~-22 WO 97/18826 PCr/US96/18544 It has been found that the peptides of the invention precipitate in MHB at concentrations greater than 128 ~g/mL.
Thus, following the NCCLS protocol would result in serial two-fold dilutions cont~;n;ng less peptide than calculated, - 5 yielding erroneously high MIC values.
To overcome this problem, the following modified NCCLS
assay is the preferred method for determ;ning MICs of the peptides of the invention. In the method, precipitation is avoided by preparing concentrated (10X) stock solutions of lo test peptide in a buffer that is suitable for the peptide and which does not exhibit deleterious effects on the microorganisms (0.01% v/v acetic acid, 0.1% w/v HSA)and diluting the stoc~ 1:10 into MHB cont~;n;ng the microorganisms.
PreParation of MIC assaY Plates:
1. Prepare a fresh overnight culture of test organism in Meuller-~inton broth (MHB; ~ecton-Dickinson, Cockysville, MD, BB2 #11443).
2. Dilute the culture to approximately 4x105 CFUs/mL with fresh MH~ and dispense 100 ~L aliquots into each well of a sterile 96-well microtiter plate.
3. From the peptide stock solution, prepare serial two-fold dilutions (from 1280 ~g/mL to 0.625 ~g/mL) using acetic acid (0.01~) as a diluent, or, for peptide concentrations lower than 50 ~g/mL, sodium acetate (10 mM, pH 5) containing Human Serum Albumin (HSA; 0.1%w/v) as a diluent.
4. Dispense triplicate aliquots (11 ~L) of each serial dilution into the wells of the microtiter plate.
5. T~cllb~te the plate for 16-18 hours, without aeration, at 37~C (bacteria) or 30~C (yeast).
6. Examine the plates and evaluate each well for turbidity (cell growth). Often, MRSA will settle out and form a pellet at the bottom of the well. MRSA can be evaluated by placing the microtiter plate on a stand and m; n; ng the bottom of the well using a tilted mirror.

CA 02238610 1998-0~-22 W O 97/1882G PCT~US96/18544 7. The minimum inhibitory concentration (MIC) is defined as the lowest peptide concentration that inhibits all visible growth. If the MIC values for each of the triplicate samples differ, the MIC is obt~;ne~ by averaging the results 5 of the three samples.
8. The minimum concentration of peptide showing 100% biocidal activity is determined by incubating a 10 ,uL
aliquot from each well on a TSA plate for 24 hours at 37~C
(bacteria) or 30~C (yeast) (for plating, 1.5 mL TSA in each

10 well of a 24-well plate minimizes cross contA ;nAtion).

6.8 ~inetic Bactericidal AssaY
The following assay is used to determine the rate at which a peptide kills a target microorganism, as well as 15 to determine if a peptide is bactericidal or bacteriostatic.

AssaY
1. Dispense 200 ,~lL of log-phase cells in LTM (4 x 10~ CFUs/mL) into each well of a 96-well microtiter plate 20 solution.
2. At time T=0 minutes, add 22 ,uL of 1280 ~g/mL
peptide to well Al and mix by triturating 3 times.
3. Wait 30 seconds and add 22 ,uL of a second concentration of peptide the to the next well (A2) and mix by 25 triturating 3 times.
4. Repeat the process, staggering each peptide addition by 30 seconds, until all concentrations of peptide have been added. Typically, 4-fold serial dilutions of stock peptide (l.e., 1280, 320, 80, 20 and 5 ~g/mL peptide diluted 30 1:10 into each well) produces good comparative ]cill curves.
Add 22 t~L of 0.01% acetic acid to one well as a control.
~ . At time T=15 minutes, mix well Al by triturating 3 times and transfer 20 ~L to an empty sterile petri dish (100 mm x 15 nu~).
6. Quickly add 20 mL of tempered (50~C) TSA and gently swirl plate to mix.
7. ~epeat steps 5-6 until all peptide concentrations have been plated.

CA 02238610 1998-0~-22 W O 97/l8826 PCTAUS96~8~44 8. For the control well, dilute the sample l:lOo with LTM and plate 50 ~L of the dilution to obtain an accurate determinations of CFUs.
9. After the agar has solidified, invert the ~ 5 plates and incubate at 37~C (bacteria) 30~C (yeast) for 18-24 hours.
10. Repeat steps 5-9 for all peptide concentrations and control samples at times T=30, 60, 120, and 240 minutes.

11. Count the n h~r of CFUs per plate and estimate the reduction in C~Us for each peptide concentration. In order to assess an effect using this assay, the peptide must reduce the CFUs by at least one log (i.e., at least 800 CFUs per plate). Although such numbers are higher than reco en~ed for accuracy (30-300 CFUs/plate), log-order changes in recoverable CFUs indicate significant bacteriocidal efficacy.

12. To obtain comparative kill curves, plot the log of fractional survival versus peptide concentration.
Table 21 shows the antimicrobial activity of a number of the compounds of the invention against various target orgAn;~ ~ using the MCB-3 assay described above (i.e., at 103 CFU. The results are given as a ~; n; ~ l concentration for inhibition of growth in broth" (MCB) which is the lowest concentration that results in no visible turbidity. The ~minimal bactericidal concentration~ (MBC) on TSA was e~uivalent to the MCB. The units of concentration are ~g/ml.
As shown in Table 21, various substitutions can be made in the peptide chain in order to fine-tune the spectrum of 3~ antimicrobial activity. An asterisk at the C-terminus indicates that the peptide was supplied in the form of the free acid; otherwise the amide was used in the assay.

Table 21 E~aluation of ~ntimicrobial Peptides i~ MCB-3 ~g/mh) Se~cc MRSA Psa VREF ~-n~; ~ E. coli RGGRLCYCRRRFCVCVGR* 1.5 O.ll 1.2 0.6 RGGGLCYCRRR~v~v~k* 3.29 0.4 W O 97/18826 PCT~US96/18544 SequenceMRSA Psa VREF ~n~; ~ n E . coli RGGGLCYCRR~v~n 1.93 0.14 1.62 RGGGLCY~nRP~v~v~n 3.1 0.06 7.69 0.15 RGGGL~_~nPR~v~v~K* 17.7 3.51 RGGRLCY~nkn~v~v~n* (X=MeGly) 5.33 2 RGGRLCYCRXRr~v~v~n (x=MeGly) 4 1.67 0.83 RGGL~Y~n~r~v~v~n10.6 0.83 RGGRLCYCX~Kr~v~v~n (X=CLt) XGGRLcycRGR~v~v~K (X=Cit) RG~nv~Y~nGRr'~v~v~n 8 RG~inv~:YI;n~ ~:v~;vGn*
RGGGLCY~K~v~v~k 3.48 1.2 15.96 RGWGLCYCRPR~v~v~k 1.55 0.27O.O9 5.68 O.1 RGWRLCYCR~n~v~v~n* (X=MeGly) 26.7 10.6 RGWRLCYCRGRh~v~v~n 5.3 0.5 R~RT.~Y~Kr~V~V~n (X=Cit) RWRLCYCRPRFCVCVGR 4.7 3.3 1.7 RGWRLCYCRPR~v~v~n 4.7 5.3 6.1 RGWRACYCRPRFCACVGR 4.7 1.3 2 4.7 0.34 GWRLCYCRPR~v~v~n 4.7 4 2.7 0.86 RWRL~Y~K~v~v~K
RGWRLCY~n~nr~v~v~n (X=MeGly) GGWRLCYCR~n~v~v~n 16 9.3 RGGWLCYCR~n~v~v~n 32 5.3 RLLRLCY~nkn~v~v~n (X=MeGly) 4 3.3 RLLRACYCRXRFCVCVGR (X=MeGly) 10.6 3 RLLRLCYCRRR~v~v~n RqT.R~CY~n~n~v~v~n (X=Cha) 6.7 2.3 RGGRLCYCRXRZCVCWGR (X MeGly) (Z~Cha) RG~nw~v~n~nZCYCVGR (X=MeGly) (Z=Cha) RGLRXCYCRGR~v~v~K* (X=Cha) 16 8 RG~w~v~GRXCYCVGR (xscha) RGGRL~Y~KkR~CVGR (X MeVal) LCY~K~V~V 16 4 4 5.9 1.9 LCYCRRRFCVCV* 32 8 LCYCRPCFCVCV 64 5.33.33 >64 L~Y~nRR~v~ 4 2 2 3 T C~ CRRRACVCV >64 13.3 LCYCRXRFCVCV (X=D-Arg) 4 2 1.32 5.72 1.18 L~w~nkk~v~v 5.3 2 4 8.91 O.76 ~._Y~nRRFCVCV 5.3 2.7 2 4.7 2.3 L~Y~KkR~v~v (X~hPhe) 8(64)6.7 2.7 L~K~nX~v~v (X=Phe(4-Cl)) 4 2 1.3 XCY~nkk~-~v~v (X=Cha) 2.672.67 1.33 LCYCRRRFCXCV (X=D-Hi~) >6410.7 >64 LCYCRRRXCVCV (x=MeGly) >6413.3 42.7 LCYCRRRXCVCV (X=MePhe) LCYCRRRFCXCV (X~MeVal) CA 022386l0 l998-05-22 WO 97/18826 PCTnUS96/18544 ~c~caMRSA P~a VREF ~nn~;~A E. coli T~X~k~xcvcv (xzCha) 18.7 16 8 3.98 0.37 LCGCRRRGCVCV>32 >16 >128 T~r,R~RACvCV>326.721.3 RLCY~Rkr-~v~v 8 4 RACYCRPRFCACV>642.7 RLCYCR~kr~v~r RLCYCRPR~v~v5. 32.7 2 KLCY~K~F~v~v 16 22. 67 2.07 Rr~ArRGR~r-VCV~322.710.79.51 3.93 RLCY~nkKr~v~v (X=MeGly) 5.3 2 2 6 2.54 RXCFCR~F~v~v (X~Cha) 2.67 2.67 0.83 RWCFCRPk~v~v 3.3 2 2 5.2 2.2 WLCYCRRRFCVCV5.31.3 WL~r~v~V
FL~r~KKk~v~v WL~r~KXCVCV (X=MePhe) WLCYCRRRFCVCV* 8 4 2 7.14 0.99 RLCYCRRRFCVCV* 81.67 2 WYCYCRRRFCVCV*
WXCY~K~R~v~v* (X~Cha) RXCFCRGRZCVCV (X=Cha) (Z-MePhe) XLCFCRRRZCVCV (X=Cha) (Z~MePhe) RLCY~P~r~v~v~0.65 0.1 0.89 0.05 RLCY~r~v~v~ 3. 30.71.3 3.3 0.98 RL~Y~nP~r~V~V~* 8 2.7 2 12.1 1.6 WLCY~KR~r~v~v~*
WXCY~nR~v~v~k* (X=Cha) RLCYCR~r~v~ 16.61.1 7.73 RKW~r'V~YAGFCYRCR64 8 4 RGGRL~Y~kKr~v~ >32 1.6* 2.7 RRCY~KKk~v~v~ >64 1.3 2 8.07 (32) RRCY~;K iKr CGCVGR
RWRCYC~KkrCGCVGR
RAR~Y~Kkr-CGCVGR
GWRCY~;K~Kr CGC
RGWACY~n~r~vC
RR~;Y~Rr ~. v~v~
RGWRL~_~r~v~
RGWRLCYCRGRFCVC
~Y~nRkr~V~r 53-3 4 3-33 >64 CY~r~v~v~ >64 2 21.3 RGWRLCY~Kk~r~vC (X=MeGly) RGWRGCY~K~CGC (X=MeGly) >6410.7 LCY~RRr~v~v~ 8 2 5.8 LCY~nP~v~v~ 13.3 4 LCYCK~Kr~v~v~K 64 2 LCYCRGRr~v~v~ 8 2 2 2.14 W O 97/18826 PCT~US96/18544 S~nc~MRSA P~a VR~EF ~nn~; ~ E. coli LCYCRPRr~v~v~GR 8 2 R~ ~PKF~v~vK 2.87 O.18 2.98 WRLCYCKPKr~v~v~K 5.3 4 5 GWLCY~K~'~v~v~K 21 16 RWLCYCRGRr~v~v~K 16 5.3 RLLCY~K~K~v~v~x 6.6 1.3 RWRL~Y~n~Xr~v~V 8 4 5 RXRLCYCRZRFCVCV (X=Cha) 16 5.3 (Z~MeGly) RGWRLCYCRGRXCVCV (X=Cha) 32 13.3 RGGKv~Y~KGRFCVCV 8 2 KG~Kv~YCRGRFCVCV* 64 L~Y~K~K~v~v (X=D-Ala) 32 9.3 3.33 >64 LCY~K~Kr~v~v 64 3 6.7 >64 VCYCR~Kr~v~v 26.7 5.2 5.26 LCYCRPRFCVCW53.3 42.3 LCYRRPRFRVCV >64 4 16 >64 RGWRLCYCR~Kk~v~v* (X=Cha) >32 >16 RXRLCYCRZRFCVCV* (X=Cha) >32 21 (Z=MeGly) RXRLCYCR~K~v~v (X=Cha) RGGGTcypT~r-wIAFcvGR 2.1 0.59 32.6 0.81 RGGGLCYARGFIAVCFGR 19 14 65.8 3.27 RGGC~,TCY~RPRFAVCVGR
RGGGL~Y~PR~l~v~K 8.7 0.07 >128 1.53 RGGGLCYARKGFAVCVGR >128 O.Ol >128 Z.65 RGGRLCYARRRFAVCVGR* 0.05 1.6 0.4 R4r-RT~cy~T~RRFAvcvGR O.Ol 3 0.08 Rr~GGT~;yKK~rlKv~r~K 17 O.19 7.73 3.27 RGGr-TCY~R~wlKr~v~K 2.07 0.15 2.72 3.56 RGGGLCYRL~KrKv~v~n 34.770.22 15.09 0.56 RGGGTCY~TP~r-Kv~v~K 30.760.53 31.4 8.95 RGW~G~ K ~(;K ~GCVGR >64 9.3 RGWRGCYKR~KrK~v~K* >32 8*
T~Y~RRRFAVCV >64 2 10.7 L~L~RR~ lV~V >64 4 16 LCYKR~r~v~V
I~rv~v~K >128 6.9 >128 10.78 ~ denote~ free acid form; all other~ are amide form.
MRSA i~ methicillin-re~i~tant S. aureus P~a i~ P. aeruginosa VREF i3 Vancomycin-re~i~tant E. faecium C~n~i ~A i5 C. A 7hi~
Tables 22-25 show activity in the kinetic bactericidal assay described above provided in terms of log reduction in CFUs for various peptides of the invention against MRSA, Pseudomonas aeruginosa, and the endogenous flora in saliva.

WO 97/18826 PC~US96~85 Table 22 RQ~IUCtiOn Of MRSA (ATCC 33591) CFUS after exposure to peptide ~2 ~g/ml) for 15 minutes in LTN medium at 37~
Sequence Log reduction CFUs RGGRLCYCRRRFCVCVGR 2.44 RGGRLCYCRRRFCVCVGR 1.83 RGGRLCYARRRFAVCVGR* 0.29 RWRLCYCRPRFCVCV 1.41 RGWRLCYCRPRFCVCVGR 2.06 GWRLCYCRPRFCVCVGR >3.19 XCYCRRRFCVCV (X=Cha) 1.32 LCXCRRRXCVCV (X=Cha) >3.19 RLCYCRRRFCVCV* <o,go RXRLCYCRZRFCVCV (X=Cha) 1.13 (Z=MeGly) RGLRXCYCRGRFCVCVGR (X=Cha) 2.48 RWLCYCRGRFCVCVGR 1.58 GGWRLCYCRGRFCVCVGR 2.47 RLLRLCYCRXRFCVCVGR (X=MeGly) 1.66 RGGRLCYCRGRFCVCVGR* <0.90 RXRLCYCRZRXCVCWGR* (X=Cha) 1.38 (Z=MeGly) RGWRLCYCRGRFCVCVGR 2.12 WLCYCRRRFCVCV 3.16 RLLRLCYCRRRFCVCVGR 2.16 RGGRLCYCRRRFCXCVGR (X=MeVal) <0.90 * Peptides noted with * are acid forms; all others are amide forms.
Initial inoculum approximately 4 x lOs CFUs/ml.

CA 0223s6l0 l998-0~-22 W O 97/18826 pcTrus96/l8544 T~ble 23 Log Redu¢tion of Pse~ n~ R aeruginosa (Aq~CC 90~7~ CFUs after 15 minutes expos~ure to peptide (4 ,ug/ml) in LTM medium at 37~
Sequence Log reduction CFUs RGGRLCYCRRRFCVCVGR 3.19 RGGRLCYCRPRFCVCVGR 3.65 RGWGLCYCRPRFCVCVGR <1.2 RGGGLCYTRPRFTVCVGR 2.15 RGGRLCYCRRRFCVCVGR* 3.98 XCYCRRRFCVCV (X=Cha) 2.81 RLCYCRXRFCVCV (X=MeGly) <0.5 RLCYCRPRFCVCVGR* 3.Z9 RXCFCRPRFCVCV (X=Cha) 1.78 RLCYCRRRFCVCV* 3.52 RGLRXCYCRGRFCVCVGR (X=Cha) 2.87 RGGLCYCRGRF~v~v~K 3.61 RLLRLCYCRXRFCVCVGR (X=MeGly) 2.70 RLLRACYCRXRFCVCVGR (X-MeGly) 2.71 RGGRLCYCRGRFCVCVGR* 2.66 RGWRLCYCRGRFCVCVGR 2.54 RGGRVCYCRGRFCVCVGR 2.37 RGGRVCYCRGRFCVCV 2.18 RGGRVCYCRGRFCVCV* 1.55 WLCYCRRRFCVCV 1.27 * Peptide~ noted with * are acid forms; all others are amide forms.
Initial inoculum approximately 4 x 10~ CFUq/ml.

CA 022386l0 l998-05-22 WO 97/18826 PCT~JS96~18S44 T~ble 24 Log Reduction of Pse~ aerugi~o~
(ATCC 9027) CFUs after expo~ure to peptide (0.12 ~g/ml) in LTM medium at 37~
Sequence 15 min 120 min RGGRLCYCRRRFCVCVGR 3.48 3.68 RGWGLCYCRPRFCVCVGR 3.48' 3.68 RGGGLCYTRPRFTVCVGR 0.75 3.68 RGGGLCYARKGFAVCVGR 1.20 3.68 10GWRLCYCRPRFCVCVGR 2.70 2.21 RGGRLCYCRRRFCVC 2.25 >3.73 LCYCRRRFCVCV 1.35 2.13 Initial inoculum approximately 4 x lOs CFU~/ml.

Table 25 Log Reduction of CFUs endogenous flora in saliva after 15 minute~ expo~ure to peptide (320 ~g/ml) at 37~
Sequence Log reduction CFUs RGGRLCYCRRRFCVCVGR 1.80 RGGRLCYCRPRFCVCVGR 2.04 RGGGLCYKRGWIKFCVGR 1.09 RGWGLCYCRPRFCVCVGR 0.53 25RLCYCRPRFCVCVGR 0.53 RGGGLCYTRPRFTVCVGR 1.0 5 RGGRLCYCRRRFCVCVGR* 1.25 LCYCRGRFCVCVGR 1.02 RWRLCYCRPRFCVCV 0.22 30RGWRLCYCRPRFCVCVGR 0.38 RGWRACYCRPRFCACVGR 0.28 GWRLCYCRPRFCVCVGR 0.26 XCYCRRRFCVCV (X=Cha) 0.25 WLCYCRRRFCVCV* 0.16 35RLCYCRXRFCVCV (X=MeGly) 3.43 RLCYCRPRFCVCVGR* 0.66 RGGGLCYCRPRFCVCVGR* 1.51 RXCFCRPRFCVCV (X=Cha) 0.71 W O 97/18826 PCT~US96/18544 Table 25 Log Reduction of CFUs endogenous flora in saliva ~fter 15 minutes exposure to peptide (320 ,ug/ml) at 37~
Sequence Log reduction CFUs RWCFCRPRFCVCV O.52 LCXCRRRXCVCV (X=Cha) 0.23 RGGRLCYCRRRFCVC 0.86 L~Y~l~K~FTVCV 0.64 RRCYCRRRFCVCVGR 0.98 RLCYCRRRFCVCV* 0.21 RXRLCYCRZRFCVCV (X=Cha) <0.6 (X=MeGly) RGWRLCYCRGRXCVCV (X=Cha) <O.6 RGLRXCYCRGRFCVCVGR (X=Cha) 1.65 RGWRGCYKRGRFKGCVGR <0.97 RGWRGCYCRXRFCGC (X-MeGly) <0.6 RGGLCYCRGRFCVCVGR 2.52 RLLRLCYCRXRFCVCVGR (X--MeGly) 0.65 RLLRACYCRXRFCVCVGR (X=MeGly) 2.11 RGGRLCYCRGRFCVCVGR* 2.16 RGWRLCYCRGRFCVCVGR 1.89 RGGRLCYCRGRFCVCVGR 2.53 RGGRVCYCRGRFCVCVGR 2.37 RG&RVCYCRGRFCVCV 2.07 RGGRVCYCRGRFCVCV* <0.97 WLCYCRRRFCVCV 1.87 25 * Peptide~ noted with * are acid forms; all others are amide forms.
InLtial inoculum appro~; -tely 4 x 107 CFUs/ml saliva. Peptides (3200 ~g/ml) are dissolved in 0.01% acetic acid and added as 1/10 volume to ~liva.
Kinetic experiments were also run using Haemophilus influenzae (ATCC 49247) which does not ordinarily grow on TSA, but survives several hours in LTM.
Log-phase cells (4.5 x 105 CFUs/ml in LTM) were treated with peptide and then plated onto Chocolate agar to determine 35 the number of viable CFUs. All peptides tested (acid and W O 97/18826 PCT~US96/18~44 amide forms of RGGRLCYCRRRFCVCVGR, and amide form o~
RGGLCYCRGRFCVCVGR) were rapidly bactericidal against N.
influenzae. No regrowth was observed at 240 minutes, as seen previously with P . aeruginosa .
5Finally, the assay described above was conducted using H. pylori as the target provided the results ~hown in Ta~le 26 .

Table 26 Eff~ct of peptide (32~g/ml) on CFU~ o~ Nelicobacter pylori ~ATCC 33591) in LTM a~ter 15 minute~ exposure Sequence Log reduction CFUs RGGRLCYCRRRFCVCVGR 2.90 RGWGLCYCRPRFCVCVGR 3.43 RLCYCRPRFCVCVGR 1.34 RGGGLCYTRPRFTVCVGR <1.12 RGGGLCYARKGFAVCVGR <1.2 RGGRLCYCRRRFCVCVGR* 3.00 LCYCRGRFCVCVGR <1.12 RGWRACYCRPRFCACVGR <1. 6 XCYCRRRFCVCV (X=Cha) <1.70 WLCYCRRRFCVCV* <1.6 RLCYCRXRFCVCV (X=MeGly) 1.57 RLCYCRPRFCVCVGR* <1.6 RXCFCRPRFCVCV (X=Cha) >4.66 RGGRLCYCRRRFCVC <1.2 L~Y~l~K~FTVCV <1.28 RLCYCRRRFCVCV* <1.2 RXRLCYCRZRFCVCV (X=Cha) 1.97 (Z=MeGly) RGWRLCYCRGRXCVCV (X=Cha) <1.47 RGLRXCYCRGRFCVCVGR (X=Cha) 3.22 RGGLCYCRGRFCVCVGR 1.57 RLLRLCYCRXRFCVCVGR (X=MeGly) 2.10 RLLRACYCRXRFCVCVGR (X=MeGly) 1.42 RGGRLCYCRGRFCVCVGR* 2.40 RGLRXCYCRGRFCVCVGR* (X=Cha) <1.47 RGWRLCYCRGRFCVCVGR >3.57 RGGRVCYCRGRFCVCV* <1.47 W O 97/18826 PCT~US96/18544 Sequence Log reduction CFUs WLCYCR~RFCVCV 3.36 WLCFCRRRFCVCV 1.97 FLCFCRRRFCVCV 1.99 WYCYCRRRFCVCV <1.6 WXCYCRRRFCVCV (X=Cha) <1.6 WLCYCRRRFCVCVGR <1.67 WXCYCRRRFCVCVGR (X=Cha) <1.67 RLLRLCYCRRRFCVCVGR <1.67 RGGRLCYCRRRFCXCVGR (X=MeVal) <1.67 Initial inoculum approximately 4 x 105 CFUs/ml.
Peptides denoted with * are acid forms; all others are amide forms.

The modified NCCLS assay was also used as described above, where the ini inhibitory concentration (~g/ml) is reported in Tables 28 and 29. Peptides were prepared in O.01% AA with (~HSA) or without (-HSA) human serum albumin at 0.1%. Table 28 shows the results of various peptides tested 20 agsinst various organisms; Table 29 shows the results in the presence of human serum albumin. Generally, the HSA
decreased the MICs, putatively by preventing absorption to the plastic surfaces.

Table 28 Minimum Inhibitory Concentration (~g/ml) for peptides tested in the mod~fied NCC~ a~say Se~uence P. aeruginosa MRSA V~EF
RGGRLCYCRRRr~v~v~K 8.00 8.00 2.00 30RGWGLCY~KPKr~v~v~K 16.00 16.00 RGGRL~Y~KRKr~v~v~K* 8.00 16.00 2.00 WLCY~K~r~v~v* 32.O 32.00 RGGLCY~K~Kr~v~v~K 4.00 8.00 2.00 Rr~r~R~cycRxRr~v~v~K (X=MeGly) 16.00 16.00 35WLCY~KKKr~v~v 128.00 16.00 3.00 WY~KKRr~v~v 32.0 64.00 WLCY~KkKr~v~v~K >64 64.00 RLLRLCYCRRRr~v~v~K 32.0 32.00 RGGRLCY~K~r~CVGR (X=MeVal) 64.0 >128 * Peptide~ noted with * are acid formq; all other~ are amide formq.

WO 97/18826 PC~AUS96~1~S44 Peptides were prepared in O.O1~ acetic acid without HSA.
T~ble 29 MICs ~'~g/~l) in Mueller Hinton Media Organi~ M-d~um RGG~K~K~ ~ V ~ ~ PG-l (~mide) PG-l (nmide) (acid) Suppl. - HSA + HSA - HSA + HSA - HSA
Staphylococcus aureus None 4 4 4 MSSA
Staphylococcus aureus None 13.3 2 16 5.3 16 Enterococcus faecium None 2 0.33 1.3 0.25 2 VREF
- hematin + hematin 8 ~acillu3 subtilis None o. 7 0.8 0.2 Streptococcus - hematin 2 ~n~-r~~niae~
+ hematin 8 Streptococcus - hematin o.12 sali~arius~
viridans group + hematin 0.5 Ps~ aeruginosa None 4 1.33 5.3 0.33 9.3 Klebsiella r~7 iae None 5.3 4 4 Serratia marcescens None 16 16 21 Escherichia coli None 4 0.33 5.3 0.12 4 - hematin 0.5 + hematin ' 8 ~A~ ~r-; 7us influenzae~ - hematin No growth 30+ hematin 8 Acinetobacter None 2 3 4 calocoaceticus Nei~seria meningitidis~ - hematin 8 + hematin 32 Candida albicans None 8 4 16 8 16 Table 30 shows the MICs of various peptides against a variety of microorganisms.

CA 02238610 l99s-0s-22 W O 97118826 pcTrus96ll8544 TablQ 30 MICs of Various PQptia~s MICs (~g/mL) ~riQu~:Ncri MRSA Psa VREF Can.
R~r~RT~cycnKnr CV~V~ 2 - 40.3 - 1.7 0.13 8, 16 WL~nR~r~CVCV
FLcb~K~b~v~v 5.3 >32 0.5 128 WYCY~KKK~'~V~V* 42.7 32 1 >128 WXCY~nRKr-~v~v* (X=Cha) WLCY~K~b~v~v~n* 27-32 32-530.25-0.5>128 WXCYCRRRr~v~v~K* (X=Cha) RLLRCYcnRkrcY~v~n 32 t 32 t Rr-~RT~cy~KR~c~v~n (X=MeVal) ~128t 64t R~v~vcrnnnCYCLW
h~v~vc~K~RCYCLW 10. 7 >32 0.5 32 Vcv~rn~CYCLW 16 >32 1 >128 r~vcr~RRCFCLF 16 >32 2 >128 R~v ~v ~ KRR~ y CRGGR 8 8 0.25 16 R~v~v~rnKRCYCLRGGR (all D) 21 8 4 32 R~vcvcrK~CYCLW* 53 >32 2 128 R~v~v~Y~RCYCLW (X=MeGly) 13 32 1 64 WL~rcK~ZY~v~v~K (X=MeGly) (Z=D-Arg) k~r~v~rKKv~YcLw >32 128 2 >128 WLCY~KR~r~vcv~n 11 48 0.21 128 WLCYCRR~vcvn (X=D-Arg) 5.3 32 0.25 64 WLCY~KKK~vCVGR 6.7 4.3 0.21 32 Octyl-WLCY~KKKr~v~v~n XLCYCRRRFCVCV (X=l-Nal) 4 128 0.5 >128 WL~VK* >128 >128 >32 >128 WLCRGRFCFR >128 >128 16 >128 WL~YKKV~VK 64 32 16 16 WL~YCOOOr ~V~v 2 4 0.5 64 WLCY~r-~v~v (X=Dab) 2 2 0.5 32 WLCYcn~n~v~v (all D) 1 8 0.5 128 ~wRLcycR~Kr~v~v 13.3 32 1 ~128 RwRLcycnpKr~vcv 1 4 0.5 128 OWRLCYCRPKr~v~v 1 4 0.25 128 XWRLCYCRPKr~cvcv (X~Dbu) 2.67 5 ~ 30.25 107 RwHLcycRpKr~v~v 4.3 13.30.25 ~128 WO 97/1882C PCT~US96~18544 NICs (~g~mL) ~yU~N~ MRSA Pea VREF Can.
RWKLCYCRPK~vuv 2 13.3 0~5 107 RWOLCYu~EK~v~v 1 2.7 0.25 43 RWXLCYuRPK~v~v (X=Dbu) 2 2 0~5 64 NLCYu~xKr~v~v~ (X=Tic) 5~r~K~K~YCV (X-Hyp) WL~Y~K~K~v~v (X=hCy8) 16 64 WOLCYCu~Or-~v~vO (X=Tic) 1 2 Or~v~v~OFCVCVO (X=Tic) 16 85 OWOLCYCOXOFCVCV (X=Tic) 4 11 lOO~v~OLCYCFO (X=Tic) 32 >128 NLCYuKKK~v~v 2 5.3 ONOLCYCOXOFCVCV (X=Hyp) 1 2.3 WLCYCOXOFCVCVO (X=Pba) WLCYCOOOFCVCV (all D) 15XFCYCLR~v~v~* (X-D-Arg) 8 48 WLCYCR~x~-~v~v~* (X=D-Arg) 64 48 (Z=MeGly) * Peptides denoted wLth * are acid forms; all others are amide forms MRSA is methicillin-resistant S. aureus P~a i~ P. aeruginosa VREF i~ V~nc ycin-resistant E. faecium Can is C. albicans t denotes no HSA or BSA in assay _ 99 _

Claims (38)

What Is Claimed Is:

1. An antimicrobial peptide comprising about 10-30 amino acid residues and containing the amino acid sequence:
(I) X1-X2-X3-X4-X5-C6-X7-C8-X9-X10-X11-X12-C13-X14-C155-X16-X17-X18 or a pharamceutically acceptable salt or N-terminal acylated or C-terminal amidated or esterified form thereof, wherein:
each of C8 and C13 is independently present or not present, and if present each is independently a cysteine-like, basic, small, polar/large or hydrophobic;
each of C6 and C15 is independently a cysteine-like, basic, small, polar/large or hydrophobic amino acid;
each of X1-X5 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large, or small amino acid;
each of X7 and X14 is independently a hydrophobic or a small amino acid;
each of X9 and X12 is independently present or not present;
X9-X12 taken together are capable of effecting a reverse turn when contained in the amino acid sequence of formula (I) and at least one of X9-X12 must be a basic amino acid;
each of X16-X18 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large or small amino acid;
and wherein at least about 15% up to about 50% of the amino acids comprising said antimicrobial peptide are basic amino acids such that said antimicrobial peptide has a net charge of at least +1 at physiological pH;
with the proviso that if all of X1-X4 are present and none of X1-X4 is a hydrophobic amino acid, at least one of X5, C8, X9, X12, C13 or X16 must be absent or X5 must be basic.

2. The antimicrobial peptide of Claim 1, wherein said peptide contains two disulfide bridges and is in the native form.

3. The antimicrobial peptide of Claim 1, wherein said peptide contains one disulfide bridge and is in the bullet or kite form.

4. The antimicrobial peptide of Claim 1, wherein said peptide contains no disulfide bridges and is in the snake form.

5. The antimicrobial peptide of Claim 1, wherein said peptide has a net charge of at least about +3 at physiological pH.

6. The antimicrobial peptide of Claim 1, wherein said peptide comprises about 10-24 amino acid residues and wherein:
each of C8 and C13 is independently present or not present, and if present each is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of C6 and C15 is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of X1-X5 is independently present or not present, and if present each is independently a basic or small amino acid and any two of X1-X5 may be a hydrophobic amino acid;
each of X7 and X14 is independently a hydrophobic amino acid;
each of X9 and X12 is independently present or not present, and if present each is independently a basic or hydrophobic amino acid;
X10 is a basic, hydrophobic or small amino acid or proline;
X16 is present or not present, and if present is a basic, small or hydrophobic amino acid;

each of X17 and X18 is independently present or not present, and if present each is independently a basic or small amino acid.
each of X16-X18 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large or small amino acid.

7. The antimicrobial peptide of Claim 1, wherein said peptide comprises about 10-18 amino acid residues and wherein:
each of C8 and C13 is independently present or not present, and if present each is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of C6 and C15 is independently a small, hydrophobic or polar/large amino acid or cysteine;
each of X1-X4 is independently present or not present, and if present each is independently a basic or small amino acid and any one of X1-X4 may be a hydrophobic amino acid;
each of X5 and X16 is independently present or not present, and if present each is idenpendently a hydrophobic or basic amino acid;
each of X7 and X14 is independently a hydrophobic amino acid;
X9 is present or not present, and if present is a basic or hydrophobic amino acid;
X10 is a basic or small amino acid or proline;
X11 is a basic or hydrophobic amino acid;
X12 is present or not present, and if present is a hydrophobic amino acid;
X17 present or not present, and if present is independently a small amino acid; and X18 is present or not present, and if present is a basic amino acid.

8. The antimicrobial peptide of Claim 1, wherein C6, C8, C13 and C15 are each cysteine and X7 and X14 are each independently hydrophobic amino acids.

9. The antimicrobial peptide of Claim 8, wherein X7 and X14 are each independently I, V, L, W, Y or F.

10. The antimicrobial peptide of Claim 9, wherein X7 is I, F, Y or W and X14 is I, V, L, W, Y or F.

11. The antimicrobial peptide of Claim 1, wherein X1-X4 are not present.

12. The antimicrobial peptide of Claim 1, wherein at least one of X1-X4 is a hydrophobic amino acid.

13. The antimicrobial peptide of Claim 12, wherein said hydrophobic amino acid is I, V, L, W, F or Y.

14. The antimicrobial peptide of Claim 1, wherein at least one of X9-X12 is a hydrophobic amino acid.

15. The antimicrobial peptide of Claim 1, wherein X1 and X9 are each independently R, K, Orn, Dab, Har or a hydrophobic amino acid.

16. The antimicrobial peptide of Claim 1, wherein X2 and X3 are each independently G, A, S, T, I, V, L, F, Y or W.

17. The antimicrobial peptide of Claim 1, wherein X4 is R, K, H, Orn, Dab, G, A, S, T, F, Y or W.

18. The antimicrobial peptide of Claim 1, wherein X9 is R, K, H, Orn, Dab, Har, I, V, l, Nle, W, Y or F and X12 is I, L, V, W, F or Y.

19. The antimicrobial peptide of Claim 1, wherein X9-X12, taken together are a three amino acid residue .gamma.-turn.

20. The antimicrobial peptide of Claim 1, wherein X9-X12 taken together are a four amino acid residue .beta.-turn.

21. The antimicrobial peptide of Claim 1, wherein said .beta.-turn is ZZZG, ZZZF, ZZSG, ZZAL, ZGZL, ZFZL, ZPZV, ZPZF, ZGZY, IZGZ, LZZF or YZGZ, wherein each Z is independently an L- or D- entantiomer of R, K, Dbu or Orn.

22. The antimicrobial peptide of Claim 1, wherein all of the amino acids are D-enantiomers.

23. The antimicrobial peptide of Claim 1 which is selected from the group consisting of WLCFCRRRFCVCV (SEQ ID NO:2);
FLCFCRRRFCVCV (SEQ ID NO:3);
WYCYCRRRFCVCV (SEQ ID NO:4);
WXCYCRRRFCVCV (X=Cha) (SEQ ID NO:5);
WLCYCRRRFCVCVGR (SEQ ID NO:6);
WXCYCRRRFCVCVGR (X=Cha) (SEQ ID NO:7);
RLLRLCYCRRRFCVCVGR (SEQ ID NO:8);
RGGRLCYCRRRFCXCVGR (X=MeVal) (SEQ ID NO:9);
RGVCVCFRRRCYCLW (SEQ ID NO:10);
RGVCVCFRRRCYCLW (SEQ ID NO:11);
VCVCFRRRCYCLW (SEQ ID NO:12);
FCVCFRRRCFCLF (SEQ ID NO:13);
RGVCVCFRRRCYCRGGR (SEQ ID NO:14);
RGVCVCFRRRCYCLRGGR (all D) (SEQ ID NO:15);
RGVCVCFRRRCYCLW (SEQ ID NO:16);
RGVCVCYRXRCYCLW (X=MeGly) (SEQ ID NO:17);
WLCYCRXZYCVCVGR (X=MeGly) (SEQ ID NO:18);
(Z=D-Arg) RGFCVCFRRVCYCLW (SEQ ID NO:19);
WLCYCRRRFCVCVGR (SEQ ID NO:20);
WLCYCRRXFCVCVR (X=D-Arg) (SEQ ID NO:21);
WLCYCKKKFCVCVGK (SEQ ID NO:22);
Octyl-WLCYCRRRFCVCVGR (SEQ ID NO:23);
XLCYCRRRFCVCV (X=1-Nal) (SEQ ID NO:24);

WLCRGRFCVR (SEQ ID NO:25);
WLCRGRFCFR (SEQ ID NO:26);

WLCYRRVCVR (SEQ ID NO:27);
WLCYCOOOFCVCV (SEQ ID NO:28);
WLCYCXXXFCVCV (X=Dab) (SEQ ID NO:29);
WLCYCRRRFCVCV (all D) (SEQ ID NO:30);
HWRLCYCRPKFCVCV (SEQ ID NO:31);
KWRLCYCRPKFCVCV (SEQ ID NO:32);
OWRLCYCRPKFCVCV (SEQ ID NO:33);
XWRLCYCRPKFCVCV (X=Dab) (SEQ ID NO:34);
RWHLCYCRPKFCVCV (SEQ ID NO:35);
RWKLCYCRPKFCVCV (SEQ ID NO:36);
RWOLCYCRPKFCVCV (SEQ ID NO:37);
RWXLCYCRPKFCVCV (X=Dab) (SEQ ID NO:38);
WLCYCKXKFCVCVGR (X=Tic) (SEQ ID NO:39);
FCYCKXKFCYCV (X=Hyp) (SEQ ID NO:40);
WLXYXRRRFXVXV (X=hCys) (SEQ ID NO:41);
WOLCYCOXOFCVCVO (X=Tic) (SEQ ID NO:42);
OFCVCVOXOFCVCVO (X=Tic) (SEQ ID NO:43);
OWOLCYCOXOFCVCV (X=Tic) (SEQ ID NO:44);
OFCVCXOLCYCFO (X=Tic) (SEQ ID NO:45);
WLCYCKKKFCVCV (SEQ ID NO:46);
OWOLCYCOXOFCVCV (X=Hyp) (SEQ ID NO:47);
WLCYCOXOFCVCVO (X=Pba) (SEQ ID NO:48);
WLCYCOOOFCVCV (all D) (SEQ ID NO:49);
XFCYCLRXFCVCVR (X=D-Arg) (SEQ ID NO:50);
WLCYCRRXFCVCVZX (SEQ ID NO:51);
(X=D-Arg) (Z=MeGly) PC11 LCYCRRRFCVCVGR (SEQ ID NO:52);
PC12 RCYCRRRFCVCV (SEQ ID NO:53);
PC15 RGGRLCYCRRRFCVCR (SEQ ID NO:54);
PC16 RCYCRRRFCVCR (SEQ ID NO:55);
PC17 LCYCRRRFCVCV (SEQ ID NO:56);
PC18 LCYARRRFAVCV (SEQ ID NO:57);
PC19 RCYARRRFAVCR (SEQ ID NO:58);
PC20 LAYCRRRFCVAV (SEQ ID NO:59);
PC21 RAYCRRRFCVAR (SEQ ID NO:60);

PC22 RGGRLCY RR VCV (SEQ ID NO:61);
PC31 GGRLCYCRRRFCVCV (SEQ ID NO:62);
PC32 RGRLCYCRRRFCVCV (SEQ ID NO:63);
PC33 GRLCYCRRRFCVCV (SEQ ID NO:64);
PC34 RRLCYCRRRFCVCV (SEQ ID NO:65);
PC35 RLCYCRRRFCVCV (SEQ ID NO:66);
PC36 RRCYCRRRFCVCV (SEQ ID NO:67);
PC37 CYCRRRFCVCV (SEQ ID NO:68);
PC44 RGGRLCYCRRRFCVC (SEQ ID NO:69);
PC47 RGGRLCY RRRF VCV (SEQ ID NO:70);
PC48 RGWRLCYCRRRFCVCV (SEQ ID NO:71);
PC37a CYCRRRFCVCVGR. (SEQ ID NO:72);
PC45 RGGRLCYCRRRFCV (SEQ ID NO:73);
PC72 LCYCRRRFCVC (SEQ ID NO:74);
PC64 LCYTRRRFTVCV (SEQ ID NO:75);
PC64a LTYCRRRFCVTV (SEQ ID NO:76);
PC31a GGRLCYCRRRFCVCVGR (SEQ ID NO:77);
PC32a RGRLCYCRRRFCVCVGR (SEQ ID NO:78);
PC33a GRLCYCRRRFCVCVGR (SEQ ID NO:79);
PC34a RRLCYCRRRFCVCVGR (SEQ ID NO:80);
PC35a RLCYCRRRFCVCVGR (SEQ ID NO:81);
PC36a RRCYCRRRFCVCVGR (SEQ ID NO:82);
PC44a RGGRLCYCRRRFCVCR (SEQ ID NO:83);
PC47a RGGRLCY RRRF VCVGR (SEQ ID NO:84);
PC48a RGWRLCYCRRRFCVCVGR (SEQ ID NO:85);
PC54 RGWRLAYCRRRFCVAVGR (SEQ ID NO:86);
PC61 RCYCRRRFCVCV (SEQ ID NO:87);
PC62 LCYCRRRFCVCR (SEQ ID NO:88);
PC63 VCYCFRRFCYCV (SEQ ID NO:89);
PC65 LCYTRPRFTVCV (SEQ ID NO:90);
PC66 LCYTRGRFTVCV (SEQ ID NO:91);
PC67 LCYFRRRFIVCV (SEQ ID NO:92);
PC68 LCYFRPRFIVCV (SEQ ID NO:93);
PC69 LCYTFRPRFVCV (SEQ ID NO:94);
PC70 LCYTFRGRFVCV (SEQ ID NO:95);

PC74 CYCFRRFCVC (SEQ ID NO:96);
PC77 LCYCRRRRCVCV (SEQ ID NO:97);
PC78 LCYCFRRRCVCV (SEQ ID NO:98);
PC79 LCYCRFRRCVCV (SEQ ID NO:99);
PC80 LCYCRRFRCVCV (SEQ ID NO:100);
PC81 LCYCRRFFCVCV (SEQ ID NO:101);
PC82 LCYCRFFRCVCV (SEQ ID NO:102);
PC83 LCYCFFRRCVCV (SEQ ID NO:103);
PC84 LCYCFRRFCVCV (SEQ ID NO:104);
PC85 LCYCFRFRCVCV (SEQ ID NO:105);
PC86 LCYCRFRFCVCV (SEQ ID NO:106);
PC87 LCYCFRFFCVCV (SEQ ID NO:107);
PC88 LCYCFFRFCVCV (SEQ ID NO:108);
PC89 LCYCFFFRCVCV (SEQ ID NO:109);
PC90 LCYCRFFFCVCV (SEQ ID NO:100);
RGGRLCY RR VCVGR (SEQ ID NO:111);
PC91 YCYCRRRFCVCVGR (SEQ ID NO:112);
PC95 ICYCRRRFCVCVGR (SEQ ID NO:113);
PC96 FCYCRRRFCVCVGR (SEQ ID NO:114);
PC97 WCYCRRRFCVCVGR (SEQ ID NO:115);
PC99 RCYCRRRFCVCVGR (SEQ ID NO:116);
PC109 RLCYTRGRFTVCV (SEQ ID NO:117);
PC110 LCYTRGRFTVCVR (SEQ ID NO:118);
PC111 RLCYTRGRFTVCVR (SEQ ID NO:119);
PC112 LCYCHHHFCVCV (SEQ ID NO:120);
PC113 LCYTHHHFTVCV (SEQ ID NO:121);
RGGLCYCRRRFCVCVGR (SEQ ID NO:122);
RGGRLCYCRRRFCVCVGR (SEQ ID NO:123);
RGGGLCYCRRRFCVCVGR (SEQ ID NO:124);
RGGGLCYCRRGFCVCFGR (SEQ ID NO:125);
RGGGLCYCRRPFCVCVGR (SEQ ID NO:126);
RGGGLCYCRPRFCVCVGR (SEQ ID NO:127);
RGGRLCYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:128);
RGGLCYCRGRFCVCVGR (SEQ ID NO:129);
RGGRLCYCXGRFCVCVGR (X=Cit) (SEQ ID NO:130);

XGGRLCYCRGRFCVCVGR (X=Cit) (SEQ ID NO:131);
RGGRVCYCRGRFCVCVGR (SEQ ID NO:132);
RGGGLCYCFPKFCVCVGR (SEQ ID NO:133);
RGWGLCYCRPRFCVCVGR (SEQ ID NO:134);
RGWRLCYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:135);
RGWRLCYCRGRFCVCVGR (SEQ ID NO:136);
RGWRLCYCXPRFCVCVGR (X=Cit) (SEQ ID NO: 137);
RWRLCYCRPRFCVCVGR (SEQ ID NO:138);
RGWRLCYCRPRFCVCVGR (SEQ ID NO:139);
RGWRACYCRPRFCACVGR (SEQ ID NO:140);
GWRLCYCRPRFCVCVGR (SEQ ID NO:141);
RWRLCYCKGKFCVCVGR (SEQ ID NO:142);
RGWRLCYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:143);
GGWRLCYCRGRFCVCVGR (SEQ ID NO:144);
RGGWLCYCRGRFCVCVGR (SEQ ID NO:145);
RLLRLCYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:146);
RLLRACYCRXRFCVCVGR (X=MeGly) (SEQ ID NO:147);
RLLRLCYCRRRFCVCVGR (SEQ ID NO:148);
RGLRXCYCRGRFCVCVGR (X=Cha) (SEQ ID NO:149);
RGGRLCYCRXRZCVCWGR (X=MeGly) (SEQ ID NO:150);
(Z=Cha) RGGRWCVCRXRZCYCVGR (X=MeGly) (SEQ ID NO:151);
(Z=Cha) RGLRXCYCRGRFCVCVGR (X=Cha) (SEQ ID NO:152);
RGGRWCVCRGRXCYCVGR (X=Cha) (SEQ ID NO:153);
RGGRLCYCRRRFCXCVGR (X=MeVal) (SEQ ID NO:154);
LCYCRRRFCVCV (SEQ ID NO:155);
LCYCRRCFCVCV (SEQ ID NO:156);
LCYCRRRFCVCF (SEQ ID NO:157);
LCACRRRACVCV (SEQ ID NO:158);
LCYCRXRFCVCV (X=D-Arg) (SEQ ID NO:159);
LCWCRRRFCVCV (SEQ ID NO:160);
WCYCRRRFCVCV (SEQ ID NO:161);
LCYCRRRXCVCV (X=hPhe) (SEQ ID NO:162);

LCYCRRRXCVCV (X=Phe(4-Cl)) (SEQ ID NO:163);
XCYCRRRFCVCV(X=Cha) (SEQ ID NO:164);

LCYCRRRFCXCV (X=D-His) (SEQ ID NO:165);
LCYCRRRXCVCV (X=MeGly) (SEQ ID NO:166);
LCYCRRRXCVCV (X=MePhe) (SEQ ID NO:167);
LCYCRRRFCXCV (X=MeVal) (SEQ ID NO:168);
LCXCRRRXCVCV (X=Cha) (SEQ ID NO:169);
LCGCRRRGCVCV (SEQ ID NO:170);
LCACRGRACVCV (SEQ ID NO:171);
RACYCRPRFCACV (SEQ ID NO:172);
RLCYCRPRFCVCF (SEQ ID NO:173);
RLCYCRPRFCVCV (SEQ ID NO:174);
KLCYCKPKFCVCV (SEQ ID NO:175);
RLCACRGRACVCV (SEQ ID NO:176);
RLCYCRXRFCVCV (X=MeGly) (SEQ ID NO:177);
RXCFCRPRFCVCV (X=Cha) (SEQ ID NO:178);
RWCFCRPRFCVCV (SEQ ID NO:179);
WLCYCRRRFCVCV (SEQ ID NO:180);
WLCFCRRRFCVCV (SEQ ID NO:181);
FLCFCRRRFCVCV (SEQ ID NO:182);
WLCFCRRRXCVCV (X=MePhe) (SEQ ID NO:183);
WYCYCRRRFCVCV (SEQ ID NO:184);
WXCYCRRRFCVCV (X=Cha) (SEQ ID NO:185);
RXCFCRGRZCVCV (X=Cha) (SEQ ID NO:186);
(Z=MePhe) XLCFCRRRZCVCV (X=Cha) (SEQ ID NO:187);
(Z=MePhe) RLCYCRPRFCVCVGR (SEQ ID NO:188);
WLCYCRRRFCVCVGR (SEQ ID NO:189);
WXCYCRRRFCVCVGR (X=Cha) (SEQ ID NO:190);
RLCYCRGPFCVCR (SEQ ID NO:191);
RRWCFVCYAGFCYRCR (SEQ ID NO:192);
RRCYCRGRFCGCVGR (SEQ ID NO:193);
RWRCYCGRRFCGCVGR (SEQ ID NO:194);
RARCYCGRRFCGCVGR (SEQ ID NO:195);
GWRCYCRGRFCGC (SEQ ID NO:196);

RGWACYCRGRFCVC (SEQ ID NO:197);
RRCYGRRRFGVCVGR (SEQ ID NO:198);

RGWRLCYGRGRFKVC (SEQ ID NO:199);
RGWRLCYCRGRFCVC (SEQ ID NO:200);
CYCRRRFCVCF (SEQ ID NO:201);
RGWRLCYCRXRFCVC (X=MeGly) (SEQ ID NO:202);
RGWRGCYCRXRFCGC (X=MeGly) (SEQ ID NO:203);
LCYCRPRFCVCVGR (SEQ ID NO:204);
LCYCKPKFCVCVGK (SEQ ID NO:205);
LCYCRPRFCVCVGR (SEQ ID NO:206);
LCYCRPRFCVCVGRGR (SEQ ID NO:207);
RRWCYCRPRFCVCVR (SEQ ID NO:208);
WRLCYCRPRFCVCVGR (SEQ ID NO:209);
GWLCYCRGRFCVCVGR (SEQ ID NO:210);
RWLCYCRGRFCVCVGR (SEQ ID NO:211);
RLLCYCRGRFCVCVGR (SEQ ID NO:212);
RWRLCYCRPRFCVCV (SEQ ID NO:213);
RXRLCYCRZRFCVCV (X=Cha) (SEQ ID NO:214);
(Z=MeGly) RGWRLCYCRGRXCVCV (X=Cha) (SEQ ID NO:215);
RGGRVCYCRGRFCVCV (SEQ ID NO:216);
LCYCRXRFCVCV (X=D-Ala) (SEQ ID NO:217);
LCYCKPKFCVCV (SEQ ID NO:218);
VCYCRPRFCVCV (SEQ ID NO:219);
LCYCRPRFCVCW (SEQ ID NO:220);
LCYRRPRFRVCV (SEQ ID NO:221);
RGWRLCYCRGRXCVCV (X=Cha) (SEQ ID NO:222);
RXRLCYCRZRFCVCV (X=Cha) (SEQ ID NO:223);
(Z=MeGly) RXRLCYCRGRFCVCV (X=Cha) (SEQ ID NO:224);
RGGGLCYARGWIAFCVGR (SEQ ID NO:225);
RGGGLCYARGFIAVCFGR (SEQ ID NO:226);
RGGGLCYARPRFAVCVGR (SEQ ID NO:227);
RGGGLCYTRPRFTVCVGR (SEQ ID NO:228);
RGGGLCYARKGFAVCVGR (SEQ ID NO:229);
RGGRLCYARRRFAVCVGR (SEQ ID NO:230);

RGGGLCYKRGFIKVCFGR (SEQ ID NO:231);
RGGGLCYKRGWIKFCVGR (SEQ ID NO:232);

RGGGLCYRLPKFRVCVGR (SEQ ID NO:233);
RGGGLCYRLPGFRVCVGR (SEQ ID NO:234);
RGWRGCYKRGRFKGCVGR (SEQ ID NO:235);
LCYKRGRFKVCV (SEQ ID NO:236);
ICYRPRFVCVGR (SEQ ID NO:237);
WLCYCRRRFCVCV (SEQ ID NO:238);
RLCYCRRRFCVCV (SEQ ID NO:240);
RGRVCLRYCRGRFCVRLCFR (SEQ ID NO:241); and RRRLCYCRRRFCVCVGR (SEQ ID NO:242).

24. A recombinant expression system for production of the antimicrobial peptide according to Claim 1, which expression system comprises a nucleotide sequence encoding said peptide operably linked to control sequences for effecting expression.

25. A recombinant host cell, or progeny thereof, modified to contain the expression system of Claim 25.

26. A method of producing an antimicrobial peptide or intermediate peptide therefor, said method comprising the steps of culturing the modified host cell or progeny thereof according to Claim 24 under conditions wherein said peptide is produced; and recovering the antimicrobial peptide from the culture.

27. An antimicrobial pharmaceutical composition comprising an antimicrobial peptide according to Claim 1 in admixture with at least one pharmaceutically acceptable carrier, diluent or excipient.

28. An antimicrobial environmental composition for application to plants comprising an antimicrobial peptide according to Claim 1 in admixture with at least one environmentally acceptable carrier, diluent or excipient.

29. A method to prevent the growth of a virus or microbe comprising the step of contacting a composition which supports the growth of said virus or microbe with an amount of an antimicrobial peptide according to Claim 1 effective to prevent said growth.

30. A method to inactivate the endotoxin of Gram-negative bacteria comprising the step of contacting said endotoxin with an amount an antimicrobial peptide according to Claim 1 effective to inactivate said endotoxin.

31. Antibodies specifically reactive with the antimicrobial peptide of Claim 1.

32. A method to treat or prevent a microbial or viral infection in a subject comprising the step of administering to a subject in need of such treatment a therapeutically effective amount of an antimicrobial peptide comprising about 10-30 amino acid residues and containing the amino acid sequence:

(I) X1-X2-X3-X4-X5-C6-X7-C8-X9-X10-X11-X12-C13-X14-C155-X16-X17-X18 or a pharamceutically acceptable salt or N-terminal acylated or C-terminal amidated or esterified form thereof, wherein:
each of C8 and C13 is independently present or not present, and if present each is independently a cysteine-like, basic, small, polar/large or hydrophobic;
each of C6 and C15 is independently a cysteine-like, basic, small, polar/large or hydrophobic amino acid;
each of X1-X5 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large, or small amino acid;

each of X7 and X14 is independently a hydrophobic or a small amino acid;
each of X9 and X12 is independently present or not present;
X9-X12 taken together are capable of effecting a reverse turn when contained in the amino acid sequence of formula (I) and at least one of X9-X12 must be a basic amino acid;
each of X16-X18 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large or small amino acid;
and wherein at least about 15% up to about 50% of the amino acids comprising said antimicrobial peptide are basic amino acids such that said antimicrobial peptide has a net charge of at least +1 at physiological pH;

33. The method of Claim 32 wherein the microbial infection is caused by Staphylococcus aureus.

34. The method of claim 31, wherein the antimicrobial peptide is selected from the group consisting of:
RGWRLCYCRPRFCVCVGR (SEQ ID NO:139);
GWRLCYCRPRFCVCVGR (SEQ ID NO: 141);
XCYCRRRFCVCV (X=Cha) (SEQ ID NO: 164); and WLCYCRRRFCVCV (SEQ ID NO: 180).

35. The method of claim 32, wherein the microbial infection is caused by Pseudomonas.

36. The method of Claim 35, wherein the antimicrobial peptide is selected from the group consisting of:
RGGRLCYCRRRFCVCVGR (SEQ ID NO:1);
RGGRLCYCRPRFCVCVGR (SEQ ID NO:239);
RGGGLCYTRPRFTCVGR (SEQ ID NO:228); and RLCYCRRRFCVCV (SEQ ID NO:66).

37. The method of Claim 32, wherein the microbial infection is caused by H. pylori.

38. The method of Claim 37, wherein the antimicrobial peptide is selected from the group consisting of:
WLCYCRRRFCVCV (SEQ ID NO:180);
RXCFCRPRFCVCV (X=Cha) (SEQ ID NO:178);
RGGRLCYCRRRFCVCVGR (SEQ ID NO:1);
RGWGLCYCRPRFCVCVGR (SEQ ID NO:134);
RLCYCRPRFCVCVGR (SEQ ID NO:138);
RGWRLCYCRGRFCVCVGR (SEQ ID NO:136);
RGRVCLRYCRGRFCVRLCFR (SEQ ID NO:241);
RGLRXCYCRGRFCVCVGR (X=Cha)(SEQ ID NO:149);
GWRLCYCRPRFCVCVGR (SEQ ID NO:139);
RLCYCRRRFCVCV (SEQ ID NO:66);
WLCYCXXXFCVCV (X=Dab) (SEQ ID NO:29);
OWRLCYCRPKFCVCV (SEQ ID NO:33);
RWOLCYCRPKFCVCV (SEQ ID NO:37);
RRCYCRRRFCVCVGR (SEQ ID NO:82);
XCYCRRRFCVCV (X-Cha) (SEQ ID NO:164);
RRRLCYCRRRFCVCVGR (SEQ ID NO:242); and RRRLCYCRRRFCVCVGR (all D) (SEQ ID NO:243).