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WO1999021879A1 - Peptides cycliques ayant une activite antimicrobienne a large spectre - Google Patents

Peptides cycliques ayant une activite antimicrobienne a large spectre Download PDF

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Publication number
WO1999021879A1
WO1999021879A1 PCT/US1997/019557 US9719557W WO9921879A1 WO 1999021879 A1 WO1999021879 A1 WO 1999021879A1 US 9719557 W US9719557 W US 9719557W WO 9921879 A1 WO9921879 A1 WO 9921879A1
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Prior art keywords
seq
cyclo
peptide
amino acid
information
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PCT/US1997/019557
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English (en)
Inventor
Conway Chang
Leo Gu
Jie Chen
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Intrabiotics Pharmaceuticals, Inc.
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Application filed by Intrabiotics Pharmaceuticals, Inc. filed Critical Intrabiotics Pharmaceuticals, Inc.
Priority to AU51535/98A priority Critical patent/AU5153598A/en
Priority to PCT/US1997/019557 priority patent/WO1999021879A1/fr
Publication of WO1999021879A1 publication Critical patent/WO1999021879A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K7/00—Peptides having 5 to 20 amino acids in a fully defined sequence; Derivatives thereof
    • C07K7/64—Cyclic peptides containing only normal peptide links

Definitions

  • the present invention is directed to cyclic peptides having broad spectrum antimicrobial activity.
  • the cyclic peptides are biocidal against a wide variety of pathogens, including clinically relevant vancomycin resistant Enterococcus faecium, methicillin resistant Staphylo coccus aureus and penicillin-resistant Streptococcus pneumoniae .
  • the cyclic peptides of the invention have improved efficacy, bioavailability and/or serum half-life as compared to non- cyclized analogues.
  • cyclic peptides related to the tachyplesin and protegrin classes of antimicrobial peptides exhibit broad spectrum antimicrobial activity typically associated with these classes of peptides while overcoming many of the disadvantages of peptide therapeutics discussed above.
  • the cyclic peptides are ideally suited for use as antimicrobial therapeutic agents.
  • cyclic peptides are more resistant to proteolytic degradation and therefore have a greater potential for oral administration and/or lower dosage levels than non-cyclized peptides.
  • Cyclization also confers structural stability without interfering with the side chains necessary for bioactivity, potentially leading to greater efficacy. Cyclic analogues of the various known classes of antimicrobial peptides have not been reported in the literature.
  • the present invention provides cyclic peptides having antimicrobial activity.
  • the cyclic peptides of the invention are generally comprised of about 10-30 amino acid residues and may contain regions or segments of peptidomimetic moieties.
  • the cyclic peptides are characterized by a structure containing three main elements or domains: an amphiphilic anti-parallel /3-sheet region, a /3-turn region and a loop region.
  • Each strand of the amphiphilic anti-parallel .-sheet region comprises about 3 to 11 amino acid residues, with each strand having the same number of residues.
  • the /3-sheet is amphiphilic, i.e., one surface of the /3-sheet has a net hydrophobic character and the other surface has a net hydrophilic character.
  • the amphiphilic /3-sheet region may optionally contain zero, one or two interstrand disulfide interlinkages .
  • the j ⁇ -turn region reverses the direction of the polypeptide chain so as to allow a portion of the polypeptide chain to adopt an anti-parallel /3-sheet secondary structure.
  • the /3-turn region comprises a four amino acid residue peptide segment.
  • the two internal amino acid residues of the /3-turn are not involved in the hydrogen- bonding of the /3-sheet; the two amino acid residues on either side of the internal residues are included in the hydrogen- bonding of the j3-sheet.
  • the / 3-turn region may comprise an organic molecule that mimics the structure of a peptide /3-turn.
  • the loop region links the anti- parallel strands comprising the /3-sheet region.
  • the loop region comprises a two to four amino acid residue reverse-turn such as a ⁇ -turn or a (3-turn.
  • the loop region may comprise an organic molecule that mimics the structure of a peptide reverse-turn.
  • the cyclic peptides of the invention are basic, i.e., they have a net positive charge at physiological pH.
  • about 15% to 50% of the amino acid residues comprising the peptide are basic amino acid residues.
  • At least one amino acid residue in the loop or /3-turn region of the peptide is a basic amino acid residue.
  • the invention is directed to cyclic peptides having the formula:
  • ⁇ 2i' ⁇ 22 ⁇ 2 ⁇ 25' ⁇ 27 an ⁇ 3- ⁇ 28 are each independently present or absent;
  • X 7 and X 14 are either both present or both absent; X 8 and X 13 are either both present or both absent;
  • X 27 and X 28 are each independently a hydrophobic amino acid, a hydrophilic amino acid or a small amino acid, with the provisos that (i) when X 2 is a hydrophobic amino acid X 7 , X 14 , X 19 , X 21 and X 28 are each independently a hydrophobic amino acid or a small amino acid and X 3 , X 8 , X 13 , X 18 , X 22 and X 27 are each independently a hydrophilic amino acid or a small amino acid; and (ii) when X 2 is a hydrophilic amino acid X 7 , X 14 , X 19 , X 21 and X 28 are each independently a hydrophilic amino acid or a small amino acid and X 3 , X 8 , X 13 , X 18 , X 22 and X 2 are each independently a hydrophobic amino acid or a small amino acid;
  • X 23 , X 24 , X 2 ⁇ and X 26 taken together are a loop
  • Z 1# Z 6 , Z 15 and Z 20 are each independently a hydrophilic amino acid, a small amino acid or a cysteine-like amino acid;
  • X 9 , X 10 , X X1 and X 12 taken together are a /3-turn; at least one of X 9 , X 10 , X ll; X 12 , X 23 , X 24 , X 25 or X 26 is a basic amino acid; and wherein the peptide has a net positive charge at physiological pH.
  • the cyclic 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, medicaments or other nutrient-containing materials. The peptides are also useful for prophylaxis or treatment of microbial infections or diseases related thereto in both plants and animals .
  • the present invention is directed to compositions comprising one or more of the above-described cyclic peptides and a carrier or excipient .
  • Such compositions are biostatic or biocidal against a wide range of microbial targets.
  • the present invention is directed to methods of using the above-described cyclic peptides, or compositions thereof, to inhibit microbial growth.
  • the method generally involves contacting a microbe with an antimicrobially effective amount of one or more of the cyclic peptides or compositions of the invention.
  • a bacteria is contacted with a bactericidally effective amount of peptide or composition.
  • the present invention is directed to methods of using the above-described cyclic peptides, or compositions thereof, to prevent or treat microbial infections or diseases related thereto in both plants and animals.
  • the method generally involves administering to a plant or animal a therapeutically effective amount of one or more of the cyclic peptides or compositions of the invention.
  • the cyclic peptides or compositions of the invention are used to treat or prevent systemic infections caused by multi-drug resistant pathogens such as vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus and penicillin- resistant Streptococcus pneumoniae .
  • FIG. 1 is a cartoon illustrating the main structural elements of the peptides of the invention
  • FIG. 2 is an illustration of a /3-sheet secondary peptide structure
  • FIG. 3 is an illustration of exemplary peptide /3-turn structures ; and FIG. 4 is an illustration of exemplary peptidomimetic j ⁇ -turn structures.
  • peptidomimetic moiety refers to an organic molecule that mimics the secondary structure of a polypeptide chain.
  • Primer structure refers to the amino acid sequence of a polypeptide chain or the chemical formula of a peptidomimetic moiety.
  • Secondary structure refers to the regular local structure of segments of polypeptide chains including, but not limited to, helices such as ⁇ -helices, extended strands such as /3-strands and sheets of extended strands such as / 3-sheets.
  • Anti-Parallel 3-Sheet refers to a secondary structure of a polypeptide chain characterized by intermolecular backbone- backbone hydrogen bonding between anti-parallel peptide strands (see, FIG. 2) .
  • an anti-parallel /3-sheet may contain as few as six amino acid residues (three amino acid residues per strand) , and may optionally contain interstrand disulfide linkages.
  • amphiphilic Anti-Parallel /3-Sheet refers to an anti-parallel (3-sheet wherein one surface has a net hydrophobic character and another surface has a net hydrophilic character. According to the usage herein, anti- parallel (3-sheets having a pair of amino acid residues flanked by disulfide bridges are explicitly included in the definition of "amphiphilic anti-parallel /3-sheet.” Thus, sequences having the following formula are explicitly included in the definition of "amphiphilic anti-parallel /3-sheet: "
  • Z l t Z 6 , Z 25 and Z 20 are each independently a cysteine- like amino acid;
  • X 2 is a hydrophobic amino acid;
  • X 19 is a hydrophobic or small amino acid; and
  • is a disulfide linkage .
  • Reverse-Turn refers to a characteristic secondary structure that links adjacent strands of an anti-parallel /3-sheet.
  • 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 (8-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. .
  • reverse-turn also includes peptidomimetic moieties that mimic the structures of peptide reverse-turns .
  • reverse-turn sequence refers to the primary structure of a reverse-turn.
  • reverse-turn sequence refers to the primary structure of the reverse-turn peptide segment.
  • reverse-turn sequence refers to the chemical formula of the reverse-turn peptidomimetic moiety.
  • ⁇ 3-Turn refers to a recognized sub-class of reverse-turns .
  • a "/3-turn” is a 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 / 3-sheet secondary structure.
  • the two internal amino acid residues of the / 3-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 /3-sheet (see, FIG. 3).
  • /3-turn expressly includes all types of peptide / 3-turns commonly known in the art including, but not limited to, type- I, type-II, type-Ill, type-I', type-II' and type-Ill' /3-turns (see, Rose et al . , 1985, Adv. Protein Chem. 37:1-109; Wilmer-White et al . , 1987, Trends Biochem. Sci. 12:189-192; ilmot et al . , 1988, J. Mol. Biol. 203:221-232; Sibanda et al . , 1989, J. Mol. Biol. 206 . : 759-777; Tramontano et al . , 1989, Proteins: Struct.
  • /3-turn sequence refers to the primary structure of the peptide /3-turn segment.
  • /3-turn sequence refers to the chemical formula of the /3-turn peptidomimetic moiety.
  • Antimicrobially effective amount refers to an amount of cyclic 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 Effective Amount” refers to an amount of cyclic 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” refers to those salts which substantially retain the antimicrobial activity of the free bases and which are obtained by reaction with inorganic acids.
  • the present invention provides cyclic peptides having antimicrobial activity, compositions comprising the cyclic peptides, methods of using the cyclic peptides (or compositions thereof) to inhibit the growth of or kill a wide variety of microbial targets and methods of using the cyclic peptides (or compositions thereof) to treat or prevent microbial infections and diseases related thereto in both plants and animals.
  • 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-negative bacteria such as Escherichia coli , Pseudomonas aeruginosa , Klebsiella ssp . , and Hemophilus influenza ; Gram-positive bacteria such as Enterococcus faecium, Staphy loco ecus aureus , the viridans group of streptococci including Streptococcus salivarius and Streptococcus mi tis; Streptococcus pneumonia ; and yeast such as Candida albicans , Candida glabrata and Candida krusei .
  • Gram-negative bacteria such as Escherichia coli , Pseudomonas aeruginosa , Klebsiella ssp .
  • Hemophilus influenza Gram-positive bacteria such as Enterococcus f
  • the cyclic peptides described herein are biostatic or biocidal against clinically relevant pathogens exhibiting multi-drug resistance such as, among others, vancomycin-resistant Enterococcus faecium (“VRE”), penicillin-resistant Streptococcus pneumoniae (“PRSP”) and methicillin-resistant Staphylococcus aureus (“MRSA”).
  • VRE vancomycin-resistant Enterococcus faecium
  • PRSP penicillin-resistant Streptococcus pneumoniae
  • MRSA methicillin-resistant Staphylococcus aureus
  • the cyclic peptides of the invention are useful as biocidal or biostatic agents in a wide variety of applications.
  • the peptides can be used to disinfect or preserve a variety of materials including medical instruments, foodstuffs, medicaments, cosmetics and other nutrient-containing materials.
  • the cyclic peptides of the invention are particularly useful as bacteriostatic or bactericidal agents against multi-drug- resistant pathogens such as VRE and MRSA in a variety of clinical settings.
  • the cyclic peptides, or compositions thereof, are also useful for the prophylaxis or treatment of microbial infections and diseases related thereto in both plants and animals.
  • diseases 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 non-cyclized antimicrobial peptides.
  • cyclic peptides described herein are related to antimicrobial peptides found naturally in plants, insects and animals, it is believed that the relatively high frequency of resistance observed for traditional antibiotics will not be observed for the cyclic peptides described herein. Additionally, the cyclic peptides described herein are more resistant to proteolytic cleavage and therefore have a longer serum and/or gut half-life than non-cyclized antimicrobial peptides, thereby providing greater potential for oral administration and lower dosage levels. Lastly, cyclization confers structural stability to the peptide, oftentimes leading to improved efficacy and concomitant lower therapeutic costs as compared to non- cyclized analogues.
  • cyclic peptides of the invention have the formula:
  • the designation X n in each case represents an amino acid at the specified position in the peptide.
  • the designation Z n represents an amino acid at the specified position and further represents those positions in the peptide which may optionally contain amino acid residues capable of forming disulfide interlinkages .
  • residues X n , X n+1 , etc. taken together comprise specified secondary structures . Some of these structures can be obtained with organic molecules that mimic the peptide secondary structure ("peptidomimetic moieties") . In these cases, the specified designations X n , X n+1 , etc. may also refer, when taken together, to the peptidomimetic moieties.
  • the peptides of the invention are cyclic and therefore do not have amino or carboxy termini, it is to be understood that the relative positions of X n and Z n in the peptides of formula I have been arbitrarily assigned for purposes of illustration and discussion only. The specified positions do not carry independent significance.
  • the amino acid residues denoted by X n or Z n 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:
  • the cyclic peptides described herein are partially defined in terms of amino acid residues of designated classes.
  • the amino acids are generally categorized into three main classes, hydrophilic amino acids, hydrophobic amino acids, and small amino acids, depending primarily on the characteristics of the amino acid side chain. These main classes are further divided into subclasses.
  • Hydrophilic amino acids include amino acids having acidic, basic or polar side chains and hydrophobic amino acids include amino acids having aromatic or apolar side chains.
  • the class of small amino acids includes amino acids having either polar or apolar side chains, but wherein the side chain does not contribute significantly to the net properties of the peptide.
  • the definitions of the classes of amino acids as used herein are as follows :
  • Hydrophobic Amino Acid refers to an amino acid having a side chain that is uncharged at physiological pH and that 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.
  • Aromatic Amino Acid refers to a hydrophobic amino acid having a side chain containing at least one ring having a conjugated ⁇ -electron system (aromatic group) .
  • Genetically encoded aromatic amino acids include phenylalanine, tyrosine and tryptophan.
  • Non-genetically encoded aromatic amino acids include phenylglycine, 2-naphthylalanine, /3-2-thienylalanine, 1, 2 , 3 , 4-tetrahydroisoquinoline-3 -carboxylic acid, 4-chloro- phenylalanine, 2-fluorophenylalanine, 3 -fluorophenylalanine and 4 -fluorophenylalanine.
  • Apolar Amino Acid refers to a hydrophobic amino acid having a side chain that is uncharged at physiological pH. Genetically encoded apolar amino acids include leucine, valine, isoleucine and methionine. Non-genetically encoded apolar amino acids include t-butylalanine, t-butylglycine, N-methylisoleucine, norleucine, N-methyl valine and cyclohexylalanine .
  • Hydrophilic Amino Acid refers to an amino acid having a side chain that is attracted by aqueous 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.
  • Acidic Amino Acid refers to a hydrophilic amino acid having a side chain pK value of less than 7. Acidic amino acids typically have negatively charged side chains at physiological pH due to loss of a hydrogen ion. Genetically encoded acidic amino acids include aspartic acid (aspartate) and glutamic acid (glutamate) .
  • Basic Amino Acid refers to a hydrophilic amino acid having a side chain pK value of greater than 7.
  • Basic amino acids typically have positively charged side chains at physiological pH due to association with hydronium ion.
  • Genetically encoded basic amino acids include the non-cyclic amino acids arginine and lysine and the cyclic amino acid histidine.
  • Non-genetically encoded basic amino acids include the non-cyclic amino acids ornithine, 2 , 3-diaminopropionic acid, 2 , 4-diaminobutyric acid and homoarginine .
  • Poly Amino Acid refers to a hydrophilic amino acid having a side chain that is uncharged at physiological pH, but that is not sufficiently repelled by aqueous solutions so as to seek inner positions in the conformation of a peptide in which it is contained when the peptide is in aqueous medium.
  • Genetically encoded polar amino acids include asparagine and glutamine.
  • Non-genetically encoded polar amino acids include citrulline, N-acetyl lysine and methionine sulfoxide.
  • Small Amino Acid refers to an amino acid having a side chain which is not sufficiently large to confer significant hydrophobicity or hydrophilicity to the peptide.
  • Small amino acids are those with side chains having four or fewer carbons when the side chain contains at least one polar group, and three or fewer carbons when the side chain does not contain a polar group.
  • Genetically encoded small amino acids include glycine, serine, alanine and threonine.
  • the gene-encoded secondary imino acid proline is also designated as a small amino acid, although it is known to affect the secondary conformation of peptide chains.
  • Non-genetically encoded small amino acids include /3-alanine, N-methyl glycine (sarcosine) and c_-aminoisobutyric acid.
  • Cysteine-Like Amino Acid refers to an amino acid 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.
  • Genetically encoded cysteine-like amino acids include cysteine.
  • Non-genetically encoded cysteine-like amino acids include homocysteine and penicillamine .
  • 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, /3-alanine (b-Ala) and other omega-amino acids such as 3-aminopropionic acid, 2 , 3-diaminopropionic acid (Dpr) , 4-aminobutyric acid and so forth; c.-aminoisobutyric acid (Aib) ; e-aminohexanoic acid (Aha) ; ⁇ -aminovaleric acid (Ava) ; N-methylglycine or sarcosine (MeGly) ; ornithine (Orn) ; citrulline (Cit) ; t-butylalanine (t-BuA) ; t-butylglycine (t-BuG) ; N-methylisoleucine (Melle) ; phenylglycine (Phg) ; cyclohexy
  • Table 1 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 cyclic peptides described herein.
  • the symbol "—" between amino acid residues A-, and/or Z n generally designates a backbone interlinkage .
  • the symbol "—” usually designates an amide linkage (-C(O)-NH) .
  • one or more amide linkages may optionally be replaced with a linkage other than amide.
  • the interlinkage designated by "—" may also be a linker.
  • a linker is a bifunctional molecule that spaces one amino acid residue from another amino acid residue in the peptide.
  • Such linkers which may be flexible, semi-rigid or rigid, are well-known in the art 0 and include polypeptides such as poly-Gly and poly-Pro, bifunctional hydrocarbons such as aminocaproic acid, ⁇ - aminovaleric acid and /3-alanine, carbohydrates, nucleic acids, and the like.
  • the cyclic peptides of the invention are 5 comprised of about 10 to 30 amino acid residues. As will be described in more detail below, certain amino acids or segments of amino acids may optionally be replaced by peptidomimetic moieties.
  • the cyclic peptides are characterized by three main structural elements or domains: 0 an amphiphilic anti-parallel /3-sheet region, a /3-turn region and a loop region. Referring to FIG. 2, the amphiphilic anti-parallel /3-sheet region comprises anti-parallel N- and C-strands non-covalently linked together via backbone- backbone hydrogen-bonds .
  • alternating amino acid 5 residues on each strand participate in interstrand hydrogen- bonds (for a detailed description of the structure of ⁇ - sheets the reader is referred to Creighton, 1993, Proteins : Structures and Molecular Properties, W.H. Freeman and Company, New York, and references cited therein) .
  • amino acid residues X 27 -X 28 -Z 1 -X 2 - (X 3 - X 4 ) m - (X 5 ) n -Z 6 -X 7 -X 8 comprise the N-strand and residues X 22 -X 21 - Z 20 -X 19 - (X 18 -X 17 ) m - (X 16 ) n -Z 15 -X 14 -X 13 comprise the C-strand.
  • Each strand is composed of about 3 to 11 amino acids residues, with each strand having the same number of residues.
  • the N- and C-strands may optionally be covalently linked via one or two disulfide bridges.
  • the / 3-sheet region of the cyclic peptides described herein is generally amphiphilic, i.e., one surface of the (3-sheet has a net hydrophobic character and the other surface has a net hydrophilic character.
  • the side chains 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 /3-sheet.
  • the side chains of L-amino acid residues adjacent to one another interstrand-wise point in the same direction so as to be positioned on the same surface of the /3-sheet.
  • an amphiphilic antiparallel / 3-sheet is obtained by selecting amino acids at each residue position so as to yield a / 3-sheet having hydrophobic side chains positioned on one surface of the sheet and hydrophilic side chains positioned on the other.
  • each side chain comprising a particular surface need not be hydrophobic or hydrophilic.
  • the surfaces may contain side chains that do not significantly alter the net character of the surface.
  • both the hydrophobic and hydrophilic surfaces may contain small amino acid side chains, as these side chains do not significantly contribute to the net character of the surface .
  • the amphiphilic anti- parallel /3-sheet region preferably has a characteristic pattern of alternating hydrophobic and hydrophilic amino acids, such that when X 2 is a hydrophobic amino acid X 7 , X 14 , X 19 , X 21 and X 28 are each independently a hydrophobic amino acid or a small amino acid and X 3 , X 8 , X 13 , X 18 , X 22 and X 27 are each independently a hydrophilic amino acid or a small amino acid and when X 2 is a hydrophilic amino acid X 7 , X 14 , X 19 , X 21 and X 28 are each independently a hydrophilic amino acid or a small amino acid and X 3 , X 8 , X 13 , X 18 , X 22 and X 27 are each independently a hydrophobic amino acid or a small amino acid.
  • Z lf Z 6 , Z 15 and Z 20 are each independently a hydrophilic amino acid, a small amino acid or a cysteine-like amino acid. Using this general structural motif one having ordinary skill in the art can easily select amino acid residues within the above-described classifications to obtain an amphiphilic anti -parallel /3-sheet region as defined herein.
  • the /3-sheet secondary structure illustrated in FIG. 2 is composed entirely of L-amino acids.
  • L-amino acids 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 /3-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 /3-sheet.
  • the /3-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 /3-sheet region as compared to peptides containing the corresponding all D- or all L-enantiomeric forms of the sheet. Enantiomeric substitutions that do not substantially affect the stability or amphiphilicity of the /3-sheet region will be readily apparent to those having skill in the art.
  • hydrophobic, hydrophilic and cysteine-like amino acids comprising the /3-sheet region are either all L-enantiomers or all D-enantiomers .
  • Small amino acids comprising the /3-sheet region may be either L-enantiomers or D-enantiomers.
  • the ⁇ - sheet region of the cyclic peptides of formula I may contain from one to four cysteine-like amino acids.
  • cysteine-like amino acids occur in pairs and participate in disulfide linkages or bridges.
  • the cyclic peptides of formula I may be mono- cyclic, bi-cyclic or tri-cyclic.
  • Tri-cyclic peptides of the invention contain two disulfide linkages
  • bi-cyclic peptides contain one disulfide linkage
  • mono-cyclic peptides contain no disulfide linkages.
  • tri- and bi-cyclic peptides of the invention include all possible permutations of disulfide bond formation, it is preferred that, when present, disulfide linkages are formed between residues Z and Z 20 and/or residues Z 6 and Z 15 , respectively.
  • the sulfur atoms involved in an interstrand disulfide bridge in a /3-sheet are not positioned within the plane defined by the interstrand backbone-backbone hydrogen-bonds ; the sulfur atoms are at an angle with respect to the j ⁇ -carbons of the bridged amino acid residues so as to be positioned on a surface of the /3-sheet.
  • the sulfur atoms of the disulfide linkages contribute to the net hydrophilicity of a surface of the /3-sheet. It is to be understood that in the peptides of formula I a (3-sheet region defined by the following formula is specifically contemplated to fall within the definition of amphiphilic antiparallel sheet as described herein:
  • Z 2 _ ⁇ 9 Z 15 wherein Z l t Z 6 , Z 25 and Z 20 are each independently a cysteine- like amino acid; X 2 is a hydrophobic amino acid; X 19 is a hydrophobic or a small amino acid; and
  • the /3-turn region of the peptides of formula I links the strands of the amphiphilic anti-parallel /3-sheet.
  • the / 3-turn region may comprise a peptide /3-turn or a peptidomimetic ⁇ -turn.
  • the jS-turn region comprises a peptide or peptidomimetic structure that reverses the direction of the polypeptide chain so as to allow a region of the peptide to adopt an anti-parallel /3-sheet secondary structure.
  • the /3-turn region may comprise any four amino acid residue peptide segment known to adopt a /3-turn secondary structure in proteins or peptides.
  • the two internal amino acid residues of the turn are usually not involved in the hydrogen-bonding of the anti-parallel ⁇ -sheet; the two amino acid residues on either side of the internal residues are usually included in the hydrogen-bonding of the /3-sheet.
  • the type-I /3-turn is compatible with any amino acid residue at positions X 9 through X 12 , except that Pro cannot occur at position X X1 .
  • Asp, Asn, Ser and Cys residues frequently occur at position X 9 , where their side chains often hydrogen-bond to the NH of residue X 1X .
  • type-II turns Gly and Asn occur most frequently at position X 1X , as they adopt the required backbone angles most easily.
  • type-I' turns have Gly at positions X 10 and X X1
  • type-II' turns have Gly at position X 10 .
  • Type-Ill turns generally can have most amino acid residues, but type- Ill' turns usually require Gly at positions X 10 and X 1X .
  • Type-VIa and Vlb turns generally have a cis peptide bond and Pro as an internal residue.
  • Preferred peptide (3-turn sequences of the invention include those typically found in the defensin and (3-defensin classes of peptides. Such peptide (3-turn sequences include, but are not limited to, the following (sequences are listed in the order :
  • APRV (SEQ ID NO: 9)
  • IPIR SEQ ID NO: 15
  • RGGI (SEQ ID NO: 23) RGWI (SEQ ID NO: 24 RGWV (SEQ ID NO: :25 RIGA (SEQ ID NO: :26 RIPA (SEQ ID NO: ;27 RIPI (SEQ ID NO: :28 RIPV (SEQ ID NO: :29 RLVF (SEQ ID NO: :30 RTSS (SEQ ID NO: :31 TTRT (SEQ ID NO: :32 VPIR (SEQ ID NO: :33 VWGR (SEQ ID NO:34 GPRI (SEQ ID NO: :35 GPRV (SEQ ID NO: :36 GRAV (SEQ ID NO: :37 GRPV (SEQ ID NO:38 INRG (SEQ ID NO: :39 LLNR (SEQ ID NO: :40 LNGR (SEQ ID NO: :41 LPNR (SEQ ID NO: :42 RNGG (SEQ ID NO:43 RNPL (SEQ ID NO: ;44
  • the /3-turn region may comprise an organic molecule or moiety that mimics the structure of a peptide j ⁇ -turn.
  • Such /3-turn peptidomimetic moieties, as well as methods for synthesizing peptides containing such moieties, are well known in art, and include, among others, those described in Giannis and Kolter, 1993, Agnew. Chem. Intl. Ed. Eng. 32:1244-1267; Kahn et al . , 1988, J. Molecular Recognition 1:75-79; and Kahn et al . , 1987, Tetrahedron Lett . 28.: 1623-1626. Exemplary peptidomimetic /3-turn moieties are illustrated in FIG. 4.
  • the loop region of the peptides of formula I connects the anti-parallel strands of the anti-parallel /3-sheet region.
  • the loop region may be comprised of amino acids or peptidomimetic moieties.
  • the loop region comprises a peptide segment that is two, three or four amino acid residues in length (residues X 24 and X 25 are each independently present or absent) .
  • Each amino acid residue X 23 , X 24 , X 25 and X 26 is independently a hydrophilic, a hydrophobic or a small amino acid.
  • the loop region comprises a two, three or four amino acid residue reverse-turn sequence.
  • reverse-turns 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; Sibanda et al . , 1989, J. Mol. Biol. 206:759-777; Tramontano et al . , 1989, Proteins : Struct . Funct .
  • IPIS SEQ ID NO:78
  • IWGV SEQ ID NO: 79
  • VWGI (SEQ ID NO: 81)
  • VWGV (SEQ ID NO: 82)
  • INGV (SEQ ID NO: 83)
  • VNGA (SEQ ID NO: 85)
  • VNGV (SEQ ID NO: 86)
  • VGW (SEQ ID NO: 90)
  • RGW (SEQ ID NO: 92)
  • VRW (SEQ ID NO: 94)
  • the loop region may comprise peptidomimetic moieties that mimic the structures of reverse- turns.
  • peptidomimetics include, e . g. , structures that mimic peptide /3-turns, as previously described.
  • the designation "-" may represent, in addition to a backbone interlinkage, a linker. Such linkers may be useful in situations where amino acid residues comprising the loop region are under significant conformational strain when connected via an amide bond or where they are relatively far apart, such as when residues X 24 and/or X 25 are absent.
  • preferred linkers are flexible bifunctional hydrocarbons and ethers such as H0 2 C- (CH 2 ) n -X and H0 2 C- (CH 2 -0-CH 2 ) n -X where X is NH 2 , OH or SH and n is 3, 4 or 5.
  • Other suitable linkers and methods for synthesizing peptides containing such linkers will be apparent to those having skill in the art.
  • the cyclic peptides of the invention are generally basic, i.e., they have a net positive charge at physiological pH. 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 net charge and some not . To fit the definition of "basic,” an excess of amino acids in the peptide molecule are positively charged at physiological pH. In preferred embodiments, at least about 15% to 50% of the amino acid residues comprising the peptides of formula I are basic amino acids.
  • the presence of a positively charged amino acid residue in either the /3-turn region or loop region of the molecule is important for antimicrobial activity. It is also believed that having a positively charged amino acid residue in either of these regions of the molecule provides the peptides with improved efficacy against antibiotic-resistant strains of bacteria.
  • at least one amino acid residue in either the loop region or the (3-turn region of the peptide is a basic amino acid residue.
  • both the j ⁇ -turn region and the loop region contain at least one basic amino acid residue.
  • peptides of formula I are defined as follows:
  • X 2i X 22 X 24 X 25 ' X 27 an d X 28 are each independently present or absent ;
  • X 7 and X 14 are either both present or both absent ;
  • X 8 and X 13 are either both present or both absent ;
  • X 27 and X 28 are each independently a hydrophobic amino acid, a hydrophilic amino acid or a small amino acid, with the provisos that (i) when X 2 is a hydrophobic amino acid X 7 , X 14 , X 19 , X 21 and X 28 are each independently a hydrophobic amino acid or a small amino acid and X 3 , X 8 , X 13 , X 18 , X 22 and X 27 are each independently a hydrophilic amino acid or a small amino acid; and (ii) when X 2 is a hydrophilic amino acid X 7 , X 14 , X 19 , X 21 and X 28 are each independently a hydrophilic amino acid or a small amino acid and X 3 , X 8 , X 13 , X 18 , X 22 and X 27 are each independently a hydrophobic amino acid or a small amino acid;
  • X 23> X 24 X 25 an & X 26 taken together are a loop; Z ⁇ , Z 6 , Z 15 and Z 20 are each independently a hydrophilic amino acid, a small amino acid or a cysteine-like amino acid;
  • X 9 , X 10 , X l and X 12 taken together are a /3-turn; at least one of X 9 , X 10 , X llf X 12 , X 23 , X 24 , X 25 or X 26 is a basic amino acid; and wherein the peptide has a net positive charge at physiological pH.
  • Preferred peptides of formula I are as follows, cyclo SVRGFRVRGF) (SEQ ID NO 100) cyclo SVR*GFSVR*GF) (SEQ ID NO 101) cyclo FVRSYVLRSV) (SEQ ID NO 102) cyclo FVPRYVLPRV) (SEQ ID NO 103) cyclo YVRGFVFGRV) (SEQ ID NO 104) cyclo CVRRYCLWRGV) (SEQ ID NO 105) cyclo CVTRYCLWRGV) (SEQ ID NO 106) cyclo CVRTYCLRGW) (SEQ ID NO 107) cyclo CVPRYCLWRGV) (SEQ ID NO 108) cyclo CVRRYCLGRW) (SEQ ID NO 109) cyclo CVRRYCLGW) (SEQ ID NO 110) cyclo CVR*RYCLWRGW) (SEQ ID NO 111) cyclo CRRRFCYDLWRGV-Dpr-V) (SEQ ID NO 112) cyclo CV-Dpr
  • the peptides of formula I are characterized by a ⁇ -sheet region having two disulfide linkages and an odd number of amino acid residues between the cysteine-like amino acids on each strand.
  • the cyclic peptides of formula I are characterized by a /3-sheet region containing an invariant conformation of two disulfide linkages (between residues Z x and Z 20 and residues Z 6 and Z 15 , respectively) and a segment of ten amino acid residues (five amino acids per /3-sheet strand) between the disulfide linkages.
  • the ten- amino acid segment is characterized by an alternating pattern of hydrophobic and hydrophilic amino acids.
  • the cyclic peptides of the invention have the formula:
  • X, X, 22 / X 24 ' X 25' X 27 and X 28 are each independently present or absent;
  • X 2 is a hydrophobic amino acid
  • X 3 , X 18 , X 22 and X 27 are each independently a hydrophilic amino acid or a small amino acid
  • X 4 , X 17 , X 19 , X 21 and X 28 are each independently a hydrophobic amino acid or a small amino acid;
  • X 23 , X 24 , X 25 and X 26 taken together are a loop;
  • Z 1# Z 6/ Z 15 and Z 20 are each cysteine, homocysteine or penicillamine ;
  • X 9 , X 10 , Xn and X 12 taken together are a /3-turn; at least one of X 9 , X 10 , X llf X 12 , X 23 , X 24 , X 25 or X 26 is a basic amino acid; and wherein the peptide has a net positive charge at physiological pH.
  • the cyclic peptides of formula I are characterized by a ⁇ -sheet region containing an invariant conformation of two disulfide linkages (between residues Z and Z 20 and residues Z 6 and Z 15 respectively) and a segment of six amino acid residues (three amino acids per / 3-sheet strand) between the disulfide linkages.
  • the six- amino acid segment is characterized by an alternating pattern of hydrophobic and hydrophilic amino acids.
  • cyclic peptides of the invention have the formula:
  • X 2i' 22 X 24 X 25 X 27 an ⁇ 3 X 28 are each independently present or absent;
  • X 2 is a hydrophobic amino acid
  • X 3 , X 18 , X 22 and X 27 are each independently a hydrophilic amino acid or a small amino acid;
  • X 4 , X 17 , X 19 , X 21 and X 28 are each independently a hydrophobic amino acid or a small amino acid;
  • X 23 24 2 5 an d X 26 taken together are a loop;
  • Z 1# Z 6 , Z 15 and Z 20 are each cysteine, homocysteine or penicillamine ;
  • X 9 , X 10 , X 1X and X 12 taken together are a /3-turn; at least one of X 9 , X 10 , X 11# X 12 , X 23 , X 24 , X 25 or X 26 is a basic amino acid; and wherein the peptide has a net positive charge at physiological pH.
  • Preferred peptides of formula III include the following: cyclo (CLRYCRRRFCVRFCLWF) (SEQ ID NO: 140) cyclo (CLRYCRR*FCVRFCLWF) (SEQ ID NO: 141) cyclo (CLRYCRPFCVSYCVRWF) (SEQ ID NO: 142) cyclo (CLRYCRIPICVRFCVPRW) (SEQ ID NO: 143) cyclo (CLRYCRF*PFCVRFCLSRW) (SEQ ID NO: 144) cyclo (CL-Dpr-YCRRRFCVDYCVRGW) (SEQ ID NO:145) cyclo (CL-Dpr-YCVRRFCVDYCVGW) (SEQ ID NO: 146) cyclo (CL-Dpr-YCRSRFCVDYCVGW) (SEQ ID NO: 147)
  • the cyclic peptides of formula I are characterized by a ⁇ -sheet region containing an invariant conformation of two disulfide linkages (between residues Z and Z 20 and residues Z 6 and Z 15 , respectively) and a segment of two amino acid residues (one amino acid per /3-sheet strand) between the disulfide linkages.
  • One of the amino acids comprising the segment is a hydrophobic amino acid; the other amino acid is a hydrophobic amino acid or a small amino acid.
  • cyclic peptides of the invention have the formula:
  • X 2 is a hydrophobic amino acid
  • X 22 and X 27 are each independently a hydrophilic amino acid or a small amino acid
  • X 19 , X 21 and X 28 are each independently a hydrophobic amino acid or a small amino acid
  • X 23' X. X, and X 26 taken together are a loop;
  • Z- L , Z 6 , Z 15 and Z 20 are each independently cysteine, homocysteine or penicillamine;
  • X 9 , X 10 , X X1 and X 12 taken together are a /3-turn; at least one of X 9 , X 10 , X 11# X 12 , X 23 , X 24 , X 25 or X 26 is a basic amino acid; and wherein the peptide has a net positive charge at physiological pH.
  • Preferred cyclic peptides of formulae IV are as follows cyclo CYCRRRFCVCVL) (SEQ ID NO 150) cyclo CYCRRRFCVCVWY) (SEQ ID NO 151) cyclo CYCRGRFCVRW) (SEQ ID NO 152) cyclo CVCFR*R*RCYCLWV) (SEQ ID NO 153) cyclo CYCRRRFCVCVRL) (SEQ ID NO 154) cyclo CVCFR*R*RCYCLRV) (SEQ ID NO 155) cyclo CYCRRRFCVCIFGR) (SEQ ID NO 156) cyclo CYCRRRFCVCISGR) (SEQ ID NO 157) cyclo CYCRRRFCVCIRGV) (SEQ ID NO 158) cyclo CYCRRRFCVCIWGR) (SEQ ID NO 159) cyclo CYCRRRFCVCRFPY) (SEQ ID NO 160) cyclo CYCRRRFCVCRGFL) (SEQ ID NO 161) cycl
  • CYCRGRFCVCVGRRGLR-Cha (SEQ ID NO:212) cyclo (CYCRGRFCVCVGRRGWRL) (SEQ ID NO: 213) cyclo (CYCRPRFCVCVGRGRWRL) (SEQ ID NO: 214) cyclo (CYCRTRFCVCVGRRGWRL) (SEQ ID NO:215) cyclo (CFCVRRFCVCFRV) (SEQ ID NO:216) cyclo (CFCRPRYCVCVR-Cha) (SEQ ID NO:217) cyclo (CFCRF*PYCVCVR-Cha) (SEQ ID NO:218) cyclo (CFCVTRYCVCVR-Cha) (SEQ ID NO:219) cyclo (CFCV-MeGly-R*YCVCYRV) (SEQ ID NO:220) cyclo (CYCRR*RFCVCVRWL) (SEQ ID NO:221) cyclo (CYCRRRFCVCVRWL) (SEQ ID NO: 222) cyclo (
  • amino acid residues comprising the segment of the ⁇ -sheet region between the disulfide linkages (residues X 2 , X 3 , X 4 , X 5 , X 16 , X 17 , X 18 and X 19 ) are selected so as to avoid juxtaposing large bulky aromatic side chains. While not intending to be bound by theory, it is believed that steric hinderance between adjacent aromatic side chains causes significant destabilization of the /3-sheet secondary structure, which results in loss of antimicrobial activity.
  • amino acid residues comprising the segment of the /3-sheet region between the disulfide linkages which are adjacent to an aromatic residue, either intrastrand-wise or interstrand-wise, are preferably polar or small amino acids.
  • preferred sequences for X 19 -X 18 -X 17 include, by way of example and not limitation, G-A-F, A-S-F, V-S-W, V-K-F, etc.
  • a person of ordinary skill in the art can easily choose particularly preferred sequences for the peptides of formulae II-IV in a similar fashion without undue experimentation.
  • cyclic peptides of formulae II-IV are as follows: cyclo (CYCRRRFCVCVWY) (SEQ ID NO: :151) cyclo (CYCRRRFCVCVRL) (SEQ ID NO: :154) cyclo (CYCRRRFCVCVGRWL) (SEQ ID NO: :196) cyclo (CYCRPRFCVCVGRGWL) (SEQ ID NO: :205) cyclo (CYCRPRFCVCVGRRGWL) (SEQ ID NO: :208) cyclo (CYCRRRFCVCVGRRGGRL) (SEQ ID NO:210) cyclo (CYCRR*RFCVCVRWL) (SEQ ID NO: :221) cyclo (CYCRRRFCVCVWL) (SEQ ID NO:240) cyclo (CVCFRRRCYCLWRGV) (SEQ ID NO:241)
  • active cyclic peptides of the invention are identified using in vi tro screening assay. Indeed, in many instances the cyclic peptides of the invention will be used in vi tro as preservatives, topical antimicrobial treatments, etc. Additionally, despite certain apparent limitations of in vi tro susceptibility tests, clinical data indicate that a good correlation exists between minimal inhibitory concentration (MIC) test results and in vivo efficacy of antibiotic compounds (Murray, 1994, Antimicrobial Susceptibility Testing, Poupard et al . , eds., Plenum Press, NY; Knudsen et al . , 1995, Antimicrob. Agents Chemother. 3.9(6) : 1253-1258) . Thus, cyclic peptides useful for treating infections and diseases related thereto are also conveniently identified by demonstrated in vi tro antimicrobial activity against specified microbial targets.
  • MIC minimal inhibitory concentration
  • the in vi tro antimicrobial activity of antimicrobial agents is tested using standard NCCLS bacterial inhibition assays, or MIC tests (see, National Committee on Clinical Laboratory Standards "Performance Standards for Antimicrobial Susceptibility Testing, " NCCLS Document M100-S5 Vol. 14, No. 16, December 1994; "Methods for dilution antimicrobial susceptibility test for bacteria that grow aerobically- Third Edition," Approved Standard M7-A3, National Committee for Clinical Standards, Villanova, PA) . It has been discovered, however, that these standard NCCLS MIC assays do not work well for identifying active peptides of the invention. Thus, preferably the compounds are screened using the modified NCCLS MIC assay and other assays provided in the Examples .
  • active peptides of the invention will exhibit MICs (as measured using the modified NCCLS assays provided in the Examples) of less than about 64 ⁇ g/mL, usually less than about 32 ⁇ g/mL, preferably less than about 16 ⁇ g/mL and most preferably less than about 4 ⁇ g/mL.
  • the cyclic peptides of the invention may be prepared using virtually any art-known technique for the preparation of cyclic peptides.
  • the peptides may be prepared in linear or non-cyclized form using conventional solution or solid phase peptide syntheses and cyclized using standard chemistries.
  • the chemistry used to cyclize the peptide will be sufficiently mild so as to avoid substantially degrading the peptide.
  • Suitable procedures for synthesizing the peptides described herein as well as suitable chemistries for cyclizing the peptides are well known in the art .
  • the chemical linkage used to covalently cyclize the peptides of the invention need not be an amide linkage. Indeed, in many instances it may be desirable to modify the N- and C-termini of the linear or non-cyclized peptide so as to provide, for example, reactive
  • linkages include, by way of example and not limitation amide, ester, thioester, CH 2 -NH, etc.
  • linkers may be desirable to attach linkers to the N- and/or C-termini to facilitate peptide
  • linkers will bear reactive groups capable of forming covalent bonds with the termini of the peptide.
  • Suitable linkers and chemistries are well-known in the art and include those previously described.
  • the peptides of the invention are cyclic, the designation of the N- and C-terminal amino acids is arbitrary.
  • the peptides of the invention can be synthesized in linear or non-cyclized form starting from any amino acid residue.
  • the peptides of the invention are synthesized in a manner so as to provide a linear or non-cyclized peptide that, when subjected to cyclization conditions, yields a substantial amount of cyclic peptide. While not intending to be bound by theory, it is believed that cyclizing the peptides of the invention in the loop region or /3-turn region is preferable to cyclizing the peptides in the /3-sheet region.
  • the amino acid residues in the loop and/or turn region readily adopt relatively stable conformations, thereby juxtaposing the N- and C-termini of the amino acids to be covalently cyclized, it is believed that cyclizing such peptides in these regions is entropically favored as compared to cyclizing the peptides in the ⁇ -sheet region of the molecule.
  • the cyclic peptides of the invention are synthesized so as to provide linear or non-cyclized peptides wherein the N- and C-terminal amino acids reside in either the loop region or the /3-turn region of the peptide.
  • One of ordinary skill in the art will be able to choose an appropriate cyclization strategy for a particular peptide sequence without undue experimentation.
  • the cyclic peptides of the invention may be prepared by way of segment condensation.
  • segment condensation techniques are well-described in the art (see, e.g., Liu et al . , 1996, Tetrahedron Lett . 32(7) :933-936; Baca, et al . , 1995, J. Am. Chem. Soc. 117:1881-1887; Tam et al . , 1995, Int . J. Peptide Protein Res. 4_5:209-216; Schn ⁇ lzer and Kent, 1992, Science 25_6: 221-225 ; Liu and Tam, 1994, J . Am . Chem . Soc .
  • the disulfide linkages in bi-cyclic and tri-cyclic peptides of the invention may be formed before or after cyclizing the peptide.
  • the disulfide linkages will add stability to the peptide structure, and because the side chain thiol groups are reactive, it is preferable to form the disulfide linkages prior to cyclizing the peptide.
  • Formation of disulfide linkages is generally conducted in the presence of mild oxidizing agents. Chemical oxidizing agents may be used, or the compounds may simply be exposed to atmospheric oxygen to effect these linkages.
  • Various methods are known in the art, including those described, for example, by Tam, J.P. et al . , 1979, Synthesis 955-957; Stewart et al . , 1984, Solid Phase Peptide Synthesis, 2d Ed. , Pierce Chemical Company Rockford, IL; Ahmed et al . , 1975, J. Biol. Chem. 250:8477-8482; and Pennington et al .
  • the peptide is composed entirely of gene-encoded amino acids, or a portion of it is so composed, the peptide or the relevant portion may also be synthesized using conventional recombinant genetic engineering techniques.
  • the isolated peptides, or segments thereof, are then cyclized or condensed, and optionally oxidized, as previously described, to yield a cyclic peptide.
  • a polynucleotide sequence encoding a linear or non-cyclized form of the cyclic peptide is inserted into an appropriate expression vehicle, i.e., a vector which contains the necessary elements for the transcription and translation of the inserted coding sequence, or in the case of an RNA viral vector, the necessary elements for replication and translation.
  • the expression vehicle is then transfected into a suitable target cell which will express the linear form of the cyclic peptide.
  • the expressed peptide is then isolated by procedures well- established in the art .
  • Methods for recombinant protein and peptide production are well known in the art (see, e.g., Maniatis et al . , 1989, Molecular Cloning A Laboratory Manual, Cold Spring Harbor Laboratory, N.Y. ; and Ausubel et al . , 1989, Current Protocols in Molecular Biology, Greene Publishing Associates and Wiley Interscience, N.Y.) .
  • host-expression vector systems may be utilized to express linear or non-cyclized forms of the cyclic peptides described herein. These include, but are not limited to, microorganisms such as bacteria transformed with recombinant bacteriophage DNA or plasmid DNA expression vectors containing an appropriate coding sequence; yeast or filamentous fungi transformed with recombinant yeast or fungi expression vectors containing an appropriate coding sequence; insect cell systems infected with recombinant virus expres- sion vectors (e.g., baculovirus) containing an appropriate coding sequence; plant cell systems infected with recombinant virus expression vectors (e.g., cauliflower mosaic virus or tobacco mosaic virus) or transformed with recombinant plasmid expression vectors (e.g., Ti plasmid) containing an appropriate coding sequence; or animal cell systems.
  • microorganisms such as bacteria transformed with recombinant bacteriophage DNA or plasmid DNA expression vectors containing an appropriate
  • non-cyclized or linear forms of the peptides of the invention may also be antimicrobial (see, e.g., U.S.S.N. 08/562,346, filed November 22, 1995, and Attorney Docket No. 22000-20540.26, filed May 17, 1996, each of which is incorporated herein in its entirety by reference)
  • expression hosts are those against which the expressed peptides are not lethal or toxic .
  • the expression elements of the expression systems vary in their strength and specificities.
  • any of a number of suitable transcription and translation elements may be used in the expression vector.
  • inducible promoters such as pL of bacteriophage ⁇ , plac, ptrp, ptac (ptrp-lac hybrid promoter) and the like may be used;
  • promoters such as the baculovirus polyhedron promoter may be used;
  • promoters derived from the genome of plant cells e.g., heat shock promoters; the promoter for the small subunit of RUBISCO; the promoter for the chlorophyll a/b binding protein
  • plant viruses e.g., the 35S RNA promoter of CaMV; the coat protein promoter of TMV
  • adenovirus late promoter e.g., the adenovirus late promoter; the vaccinia virus 7.5 K promoter
  • SV40-, BPV- and EBV-based vectors may be used with an appropriate selectable marker.
  • the expression of sequences encoding linear or non-cyclized forms of the cyclic peptides of the invention may be driven by any of a number of promoters.
  • viral promoters such as the 35S RNA and 19S RNA promoters of CaMV (Brisson et al . , 1984, Nature 310 : 511-514) , or the coat protein promoter of TMV (Takamatsu et al . , 1987, EMBO J. 3:11) may be used; alternatively, plant promoters such as the small subunit of RUBISCO (Coruzzi et al . , 1984, EMBO J.
  • Autographa californica nuclear polyhidrosis virus (AcNPV) is used as a vector to express the foreign genes.
  • the virus grows in Spodoptera frugiperda cells.
  • a coding sequence may be cloned into non-essential regions (for example the polyhedron gene) of the virus and placed under control of an AcNPV promoter (for example, the polyhedron promoter) .
  • Successful insertion of a coding sequence will result in inactivation of the polyhedron gene and production of non-occluded recombinant virus (i.e., virus lacking the proteinaceous coat coded for by the polyhedron gene) .
  • a number of viral based expression systems may be utilized.
  • a coding sequence may be ligated to an adenovirus transcription/translation control complex, e.g., the late promoter and tripartite leader sequence.
  • This chimeric gene may then be inserted in the adenovirus genome by in vi tro or in vivo recombination. Insertion in a non-essential region of the viral genome (e.g., region El or E3 ) will result in a recombinant virus that is viable and capable of expressing peptide in infected hosts. (e.g., See Logan & Shenk, 1984, Proc. Natl.
  • the vaccinia 7.5 K promoter may be used, ⁇ see, e . g. , Mackett et al . , 1982, Proc . Natl. Acad. Sci. (USA) 79:7415-7419; Mackett et al . , 1984, J. Virol. 49:857-864; Panicali et al . , 1982, Proc. Natl. Acad. Sci. 79:4927-4931) .
  • the cyclic peptides of the invention can be purified by art-known techniques such as high performance liquid chromatography, ion exchange chromatography, gel electrophoresis, affinity chromatography and the like.
  • the actual conditions used to purify a particular cyclic peptide will depend, in part, on factors such as net charge, hydrophobicity, hydrophilicity, etc., and will be apparent to those having skill in the art .
  • any antibody which specifically binds the cyclic peptide may be used.
  • various host animals including but not limited to rabbits, mice, rats, etc., may be immunized by injection with a cyclic peptide.
  • the peptide may be attached to a suitable carrier, such as BSA, by means of a side chain functional group or linkers attached to a side chain functional group.
  • adjuvants may be used to increase the immunological response, depending on the host species, including but not limited to Freund's (complete and incomplete) , mineral gels such as aluminum hydroxide, surface active substances such as lysolecithin, pluronic polyols, polyanions, peptides, oil emulsions, keyhole limpet hemocyanin, dinitrophenol , and potentially useful human adjuvants such as BCG (bacilli Calmette-Guerin) and Corynebacterium parvum.
  • Monoclonal antibodies to a cyclic peptide may be prepared using any technique which provides for the production of antibody molecules by continuous cell lines in culture.
  • Antibody fragments which contain deletions of specific 0 binding sites may be generated by known techniques.
  • such fragments include but are not limited to F(ab') 2 fragments, which can be produced by pepsin digestion of the antibody molecule and Fab fragments, which can be generated by reducing the disulfide bridges of the F(ab') 2 fragments. 5
  • Fab expression libraries may be constructed
  • the antibody or antibody fragment specific for the 0 desired cyclic peptide can be attached, for example, to agarose, and the antibody-agarose complex is used in immunochromatography to purify cyclic peptides of the invention. See, Scopes, 1984, Protein Purification: Principles and Practice, Springer-Verlag New York, Inc., NY, 5 Livingstone, 1974, Methods Enzymology: Immunoaffinity Chromatography of Proteins 34 : 723-731. 6. FORMULATION. ADMINISTRATION AND DOSAGES 6.1 Compositions and Administration
  • the cyclic peptides of the invention can be used in a wide variety of applications to inhibit the growth of or kill microorganisms.
  • the cyclic peptides can be used as disinfectants or as preservatives for materials such as foodstuffs, cosmetics, medicaments and other nutrient- containing materials.
  • the cyclic peptides can also be used to treat or prevent diseases related to microbial infection in both plants and animals.
  • the cyclic peptides can be added to the desired material singly, as mixtures of several cyclic peptides or in combination with other antimicrobial agents.
  • the cyclic peptides may be supplied as the peptide per se or may be in admixture with a variety of carriers, diluents or excipients as are well known in the art .
  • the cyclic peptides of the invention can be administered or applied singly, as mixtures of cyclic peptides, in combination with other antimicrobial or antibiotic agents or in combination with other pharmaceutically active agents.
  • the cyclic peptides can be administered or applied per se or as pharmaceutical compositions.
  • compositions comprising the cyclic peptides of the invention may be manufactured by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes.
  • Pharmaceutical compositions may be formulated in conventional manner using one or more physiologically acceptable carriers, diluents, excipients or auxiliaries which facilitate processing of the active peptides into preparations which can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen.
  • the cyclic peptides of the invention may be formulated as solutions, gels, ointments, creams, suspensions, etc. as are well-known in the art.
  • Systemic formulations include those designed for administration by injection, e.g. subcutaneous, intravenous, intramuscular, intrathecal or intraperitoneal injection, as well as those designed for transdermal, transmucosal oral or pulmonary administration.
  • the peptides of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks' s solution, Ringer's solution, or physiological saline buffer.
  • physiologically compatible buffers such as Hanks' s solution, Ringer's solution, or physiological saline buffer.
  • the solution may contain formulatory agents such as suspending, stabilizing and/or dispersing agents.
  • the peptide may be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen- free water, before use.
  • penetrants appropriate to the barrier to be permeated are used in the formulation.
  • penetrants are generally known in the art.
  • the compounds can be readily formulated by combining the active peptides with pharmaceutically acceptable carriers well known in the art.
  • Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient to be treated.
  • suitable excipients include fillers such as sugars, such as lactose, sucrose, mannitol and sorbitol; cellulose preparations such as maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl -cellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP) ; granulating agents; and binding agents.
  • disintegrating agents may be added, such as the cross-linked polyvinylpyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate .
  • solid dosage forms may be sugar-coated or enteric-coated using standard techniques.
  • suitable carriers, excipients or diluents include water, glycols, oils, alcohols, etc. Additionally, flavoring agents, preservatives, coloring agents and the like may be added.
  • compositions may take the form of tablets, lozenges, etc. formulated in conventional manner.
  • the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas .
  • a suitable propellant e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas .
  • the dosage unit may be determined by providing a valve to deliver a metered amount.
  • Capsules and cartridges of e.g. gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.
  • the compounds may also be formulated in rectal or vaginal compositions such as suppositories or retention enemas, e.g, containing conventional suppository bases such as cocoa butter or other glycerides .
  • the compounds may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection.
  • the compounds may be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.
  • suitable polymeric or hydrophobic materials for example as an emulsion in an acceptable oil
  • ion exchange resins for example as an emulsion in an acceptable oil
  • sparingly soluble derivatives for example, as a sparingly soluble salt.
  • other pharmaceutical delivery systems may be employed. Liposomes and emulsions are well known examples of delivery vehicles that may be used to deliver peptides of the invention.
  • Certain organic solvents such as dimethylsulfoxide also may be employed, although usually at the cost of greater toxicity.
  • the compounds may be delivered using a sustained-release system, such as semipermeable matrices of solid polymers containing the therapeutic agent.
  • sustained-release materials have been established and are well known by those skilled in the art.
  • Sustained-release capsules may, depending on their chemical nature, release the compounds for a few weeks up to over 100 days.
  • additional strategies for protein stabilization may be employed.
  • cyclic peptides of the invention may contain charged side chains, they may be included in any of the above-described formulations as the free bases or as pharmaceutically acceptable salts.
  • Pharmaceutically acceptable salts are those salts which substantially retain the antimicrobial activity of the free bases and which are prepared by reaction with inorganic acids. Pharmaceutical salts tend to be more soluble in aqueous and other protic solvents than are the corresponding free base forms .
  • cyclic peptides of the invention will generally be used in an amount effective to achieve the intended purpose.
  • amount used will depend on the particular application.
  • an antimicrobially effective amount of a cyclic peptide, or composition thereof is applied or added to the material to be disinfected or preserved.
  • 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 cyclic peptides, or compositions thereof, are usually added or applied to the material to be disinfected or preserved in relatively low amounts.
  • the cyclic 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 autimicrobially effective amounts of particular peptides for particular applications without undue experimentation using, for example, the in vi tro assays provided in the examples.
  • the peptides of the invention, or compositions thereof are administered or applied in a therapeutically effective amount.
  • therapeutically effective amount is meant an amount effective 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 skilled in the art, especially in light of the detailed disclosure provided herein.
  • a therapeutically effective dose can be determined using, for example, the in vi tro 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.
  • a therapeutically effective dose can be estimated initially from in vi tro assays.
  • a dose can be formulated in animal models to achieve a circulating cyclic peptide concentration range that includes the I so as determined 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 growth) or the I 100 as determined in cell culture (i.e., the concentration of peptide that is lethal to 100% of a cell culture) .
  • the I so as determined 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
  • the I 100 as determined in cell culture
  • Such information can be used to more accurately determine useful doses in humans .
  • Initial dosages can also be estimated from in vivo data, e.g., animal models, using techniques 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 administering multiple doses each day.
  • 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.
  • the amount of peptide administered 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.
  • the antimicrobial therapy may be repeated intermittently while infections 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 other antimicrobial peptides.
  • a therapeutically effective dose of the peptides described herein will provide therapeutic benefit without causing substantial toxicity.
  • Toxicity of the cyclic peptides described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the LD 50 (the dose lethal to 50% of the population) or the LD 100 (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 animal 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 administration utilized.
  • the exact formulation, route of administration 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 Pharmacological Basis of Therapeutics , Ch .1 , p .1 ) .
  • DMSO 20 mM ammonium acetate, pH 7.
  • the final concentration of peptide was about 1-8 mg/mL, the pH ranged from 7.0-7.2 and the DMSO concentration ranged from about 5- 20%.
  • the solution was stirred overnight at room temperature, and the pH adjusted to pH 5 with concentrated acetic acid.
  • the oxidized peptide was loaded onto a preparative reverse-phase HPLC column (Vydac C18, 2.2cm X 25cm, Cat. No.
  • Buffer A 0.10% (v/v) aqueous TFA
  • Buffer B 0.08% (v/v) TFA in acetonitrile.
  • Method A 224 mg purified disulfide-bridged peptide was dissolved in DMF (22 mL) and NaHC0 3 (66 mg) added. The mixture was cooled to 0°C and 36 mL DPPA added (the peptide concentration was between 1-10 mg/mL and 2-4 equivalents of DPPA were added) . The reaction mixture was stirred at 4°C for 7 days. The formation of cyclized peptide was determined by analytical HPLC (Vydac C18, 0.4cm X 25cm, Cat. No. 218TP54) using a linear gradient of 30% to 70% Buffer B (0.08% TFA/70% acetonitrile/H 2 0) over 30 min.
  • reaction mixture was diluted with 400 mL 0.1% (v/v) aqueous TFA and the cyclized peptide purified by preparative reverse-phase HPLC as described above. Fractions containing the pure cyclized peptide were pooled, the acetonitrile was stripped and the resultant aqueous solution was lyophilized to dryness. The overall yield was about 10-20%. The sequence was confirmed by mass spectrometry (MW 1897.8) .
  • Method B 435 mg of pure disulfide bridged peptide was dissolved in DMF (40mL) . The mixture was cooled to 0°C and 500 mg (15 equiv.) of DCC and 370 mg (10 equiv.) of HOBT were added. The reaction mixture was stirred overnight at room temperature. The formation of cyclized peptide was determined by analytical HPLC, as described above. The conversion yield was about 75%.
  • the reaction mixture was diluted with 900 mL 0.1% (v/v) aqueous TFA and the cyclized peptide purified by preparative HPLC as previously described. The overall yield was about 30-45%. The sequence of the cyclized peptide was confirmed by mass spectrometry (MW 1897.8).
  • Cyclo (CYCRRRFCVCVWL) (SEQ ID NO:240), cyclo (CYCRRRFCVCVWY) (SEQ ID NO: 151), cyclo (CYCRRRFCVCVGRWL) (SEQ ID N0.196), cyclo (CYCRRRFCVCVGRRGGRL) (SEQ ID NO:210) and cyclo (CYCRRRFCVCVRL) (SEQ ID NO: 154) were synthesized as described above.
  • Other cyclic peptides of the invention may be synthesized using the above-protocols or by techniques that are well-known in the art.
  • Microorganisms Escherichia coli ML-35p and vancomycin- resistant Enterococcus faecium (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.
  • Pseudo onas aeruginosa (ATCC 9027) , Candida albicans (ATCC 1023), and methicillin resistant Staphylococcus aureus ATCC 33591 were obtained from the American Type Culture Collection, Rockville, MD.
  • Microorganisms from other sources such as, for example, clinical isolates, can be used interchangeably with the above-described microorganisms in the assays described herein.
  • Trypticase Sov 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.
  • 2X Trypticase 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 phosphate 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 .
  • Phosphate-buffered saline PBS; 10 mM phosphate, 100 mM NaCl, pH 7.4) : mix 15 mL dibasic phosphate buffer (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 .
  • Phosphate 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.
  • Liguid Testing 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.
  • Agarose mix 1 g agarose (Sigma #S6013) in 80 mL deionized water, autoclave 121°C, 20 minutes.
  • Agarose 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 (50°C) agarose.
  • 2X TSB Agarose Overlay Medium dissolve 60 g TSB and 10 g agarose in 1 Liter deionized water, aliquot 100 mL per bottle, autoclave 121°C, 20 minutes, and store at room temperature .
  • Micropipettor 10-200 ⁇ L range; P20 and P200.
  • Multichannel micropipettors 10-50 ⁇ L and 50-200 ⁇ L range
  • 10 culture should be between 0.1-0.4.
  • the MCZ assay uses minimal 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 minimal nutrient buffered agarose. Agarose (not agar) is used in this gel to avoid electrostatic interactions between antimicrobial peptides and the polyanionic components of standard agar. Peptides diffuse radially into the gels from small wells and the diameter of the zone of growth inhibition is proportional to the concentration of peptide in the solution (Lehrer et al . , 1988, J. Immunol. Methods 108 : 153) . Preparation of MCZ Assay Plates:
  • the microbroth dilution method accomodates large numbers 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 microorganisms and peptide in a defined minimal nutrient buffer system that minimizes interference with the peptide' s biological activity.
  • HSA human serum albumin
  • the minimum concentration of peptide showing 5 100% biocidal activity is determined by incubating a 10 ⁇ 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) .
  • NCLS Meuller-Hinton Broth
  • the following modified NCCLS 0 assay is the preferred method for determining MICs of the cyclic peptides of the invention.
  • precipitation is avoided by preparing concentrated (10X) stock solutions of test peptide in a buffer that is suitable for the peptide and which does not exhibit deleterious 5 effects on the microorganisms (0.01% v/v acetic acid, 0.1% w/v HSA) and diluting the stock 1:10 into MHB containing the microorganisms .
  • Preparation of MIC assay plates :
  • MRSA 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 examining the bottom of the well using a tilted mirror.
  • 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 obtained by averaging the results of the three samples .
  • the minimum concentration of peptide showing 100% biocidal activity is determined by incubating a 10 ⁇ 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) .
  • the following assay is used to determine the rate at which a cyclic peptide kills a target microorganism, as well as to determine if a cyclic peptide is bactericidal or bacteriostatic .
  • Psa is Pseudo_no_as aeruginosa

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Abstract

Cette invention se rapporte à des peptides cycliques ayant une activité antimicrobienne à large spectre. Ces peptides possèdent une efficacité, une biodisponibilité et/ou une demi-vie sérique accrues par rapport à des analogues non cyclisés.
PCT/US1997/019557 1997-10-27 1997-10-27 Peptides cycliques ayant une activite antimicrobienne a large spectre WO1999021879A1 (fr)

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AU51535/98A AU5153598A (en) 1997-10-27 1997-10-27 Cyclic peptides having broad spectrum antimicrobial activity
PCT/US1997/019557 WO1999021879A1 (fr) 1997-10-27 1997-10-27 Peptides cycliques ayant une activite antimicrobienne a large spectre

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1373304A1 (fr) * 2001-03-12 2004-01-02 CTT Cancer Targeting Technologies OY PEPTIDES ACTIVANT L'INTEGRINE ALPHA IIb BETA 3 ET LEUR UTILISATION
GB2408263A (en) * 2003-11-14 2005-05-25 Pacgen Biopharmaceuticals Inc Antimicrobial peptides with reduced hemolysis and methods of their use.
US7361636B2 (en) 2004-10-06 2008-04-22 Amr Technology, Inc. Cyclosporin alkynes and their utility as pharmaceutical agents
US7378391B2 (en) 2004-09-29 2008-05-27 Amr Technology, Inc. Cyclosporin alkyne analogues and their pharmaceutical uses
US7511013B2 (en) 2004-09-29 2009-03-31 Amr Technology, Inc. Cyclosporin analogues and their pharmaceutical uses
US7538084B2 (en) 2003-03-17 2009-05-26 Amr Technology, Inc. Cyclosporins
WO2019166347A1 (fr) * 2018-02-27 2019-09-06 Lipotrue, S.L. Peptides et compositions pour utilisation en cosmétique et médecine
US11021518B2 (en) * 2019-06-26 2021-06-01 The University Of Southern California Theta defensin analogs

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5039789A (en) * 1988-04-11 1991-08-13 Eli Lilly And Company A54145 cyclic peptides

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5039789A (en) * 1988-04-11 1991-08-13 Eli Lilly And Company A54145 cyclic peptides

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1373304A1 (fr) * 2001-03-12 2004-01-02 CTT Cancer Targeting Technologies OY PEPTIDES ACTIVANT L'INTEGRINE ALPHA IIb BETA 3 ET LEUR UTILISATION
US7538084B2 (en) 2003-03-17 2009-05-26 Amr Technology, Inc. Cyclosporins
GB2408263A (en) * 2003-11-14 2005-05-25 Pacgen Biopharmaceuticals Inc Antimicrobial peptides with reduced hemolysis and methods of their use.
US7378391B2 (en) 2004-09-29 2008-05-27 Amr Technology, Inc. Cyclosporin alkyne analogues and their pharmaceutical uses
US7511013B2 (en) 2004-09-29 2009-03-31 Amr Technology, Inc. Cyclosporin analogues and their pharmaceutical uses
US7361636B2 (en) 2004-10-06 2008-04-22 Amr Technology, Inc. Cyclosporin alkynes and their utility as pharmaceutical agents
US7632807B2 (en) 2004-10-06 2009-12-15 Albany Molecular Research, Inc. Cyclosporin alkynes and their utility as pharmaceutical agents
WO2019166347A1 (fr) * 2018-02-27 2019-09-06 Lipotrue, S.L. Peptides et compositions pour utilisation en cosmétique et médecine
CN112040969A (zh) * 2018-02-27 2020-12-04 利波特鲁有限公司 用于化妆品和医药的肽和组合物
US11634458B2 (en) 2018-02-27 2023-04-25 Lipotrue, S.L. Peptides and compositions for use in cosmetics and medicine
US11021518B2 (en) * 2019-06-26 2021-06-01 The University Of Southern California Theta defensin analogs

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