title: Interaction of cationic antimicrobial peptides with model membranes.
abstract: A series of natural and synthetic cationic antimicrobial peptides from various structural classes, including alpha-helical, beta-sheet, extended, and cyclic, were examined for their ability to interact with model membranes, assessing penetration of phospholipid monolayers and induction of lipid flip-flop, membrane leakiness, and peptide translocation across the bilayer of large unilamellar liposomes, at a range of peptide/lipid ratios. All peptides were able to penetrate into monolayers made with negatively charged phospholipids, but only two interacted weakly with neutral lipids. Peptide-mediated lipid flip-flop generally occurred at peptide concentrations that were 3- to 5-fold lower than those causing leakage of calcein across the membrane, regardless of peptide structure. With the exception of two alpha-helical peptides V681(n) and V25(p,) the extent of peptide-induced calcein release from large unilamellar liposomes was generally low at peptide/lipid molar ratios below 1:50. Peptide translocation across bilayers was found to be higher for the beta-sheet peptide polyphemusin, intermediate for alpha-helical peptides, and low for extended peptides. Overall, whereas all studied cationic antimicrobial peptides interacted with membranes, they were quite heterogeneous in their impact on these membranes.
authors.affiliation: Department of Microbiology and Immunology, University of British Columbia, 300-6174 University Boulevard, Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: A
authors.initials: A
authors.lastname: Rozek
authors.forename: R E
authors.initials: RE
authors.lastname: Hancock
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001692:Biological Transport; D002412:Cations; D005452:Fluoresceins / Q000378:metabolism; D008567:Membranes, Artificial; D008954:Models, Biological; D008969:Molecular Sequence Data; D010455:Peptides
chemical_list: D000900:Anti-Bacterial Agents; D002412:Cations; D005452:Fluoresceins; D008567:Membranes, Artificial; D010455:Peptides; C007740:fluorexon