Parevins and tachytegrins

An antimicrobial compound composed of 11-24 amino acid residues comprising the amino acid sequence:

• A1-A2-A3-C4-C5-C6-A7-C8-A9-A10-A11-A12-C13-A14-C15-C16-C17-A18
• or a pharmaceutically acceptable salt or an N-terminal acylated or C-terminal amidated or esterified form thereof, wherein:
• each of A1-A3 is independently present or not present, and if present each is independently a basic, hydrophobic, polar/large, or small amino acid;
• each of C4 and C17 is independently present or not present, and if present each is independently selected from the group consisting of a thiol-containing amino acid, a basic amino acid, a hydrophobic amino acid, a polar/large amino acid and a small amino acid;
• C5 is selected from the group consisting of a thiol-containing amino acid, a basic amino acid, a hydrophobic amino acid, a polar/large amino acid and a small amino acid;
• each of C8 and C13 is independently a thiol-containing amino acid;
• each of C6and C15 is independently selected from the group consisting of a thiol-containing amino acid, a basic amino acid, a hydrophobic amino acid, a polar/large amino acid, a small amino acid and an acidic amino acid;
• C16 is selected from the group consisting of a thiol-containing amino acid, a hydrophobic amino acid or a small amino acid;
• each of A7 and A14 is independently a hydrophobic or a small amino acid;
• A9-A12 taken together are capable of effecting a β-turn when contained in the compound and at least one of A9-A12 is a basic amino acid;
• A18 is present or not present, and if present, is a basic, hydrophobic, polar/large, or small amino acid;
• at least about 15% to about 50% of the amino acid residues composing said compound are basic amino acids;
• and
• said compound has a net positive charge of at least +1 at physiological pH;
• with the provisos that:
• (i) when one of C4, C5 or C6 is a thiol-containing amino acid, the other two are other than a thiol-containing amino acid;
• (ii) when one of C15, C16 or C17 is a thiol-containing amino acid, the other two are other than a thiol-containing amino acid;
• and (iii) the compound has one feature selected from the group consisting of:
• (1) C4 and C15 are each independently a thiol-containing amino acid;
• (2) C4 and C16 are each independently a thiol-containing amino acid;
• (3) C4 and C17 are each independently a thiol-containing amino acid;
• (4) C5 and C15 are each independently a thiol-containing amino acid;
• (5) C5 and C16 are each independently a thiol-containing amino acid;
• (6) C6 and C16 are each independently a thiol-containing amino acid;
• and
• (7) C6 and C17 are each independently a thiol-containing amino acid.