Sequence analysis and membrane partitioning energies of α-helical antimicrobial peptides

Abstract

Sequences of 221 α-helical antimicrobial peptides (αAMPs) were compared and 63-166 of them were selected and analyzed using Perl programs. The results showed that aliphatic amino acids Gly, Leu, Ala, Ile and two positively charged amino acids Lys and Arg were composed of more than 63% of the first 20 residues of αAMPs. The weighed mean membrane partitioning energies at positions from 1 to 25 of αAMPs were calculated. Profile of the partitioning energies suggests oblique membrane insertion and an amphipathic α-helical structure of the N-terminus of αAMP (residues from 1 to 13), a bend structure at positions 13 and 14, and a less structured C-terminus that parallels the surface of the membrane. These structural features are in good agreement with the experimentally determined membrane structure of hemagglutinin fusion peptide from influenza virus. We hypothesize that this (N-terminal oblique α-helix) - central bend - (C-terminus) could be a common structural motif of membrane-disruptive peptides. © Oxford University Press 2004; all rights reserved.