title: Interaction between a cationic surfactant-like peptide and lipid vesicles and its relationship to antimicrobial activity.
abstract: We investigate the properties of an antimicrobial surfactant-like peptide (Ala)6(Arg), A6R, containing a cationic headgroup. The interaction of this peptide with zwitterionic (DPPC) lipid vesicles is investigated using a range of microscopic, X-ray scattering, spectroscopic, and calorimetric methods. The β-sheet structure adopted by A6R is disrupted in the presence of DPPC. A strong effect on the small-angle X-ray scattering profile is observed: the Bragg peaks from the DPPC bilayers in the vesicle walls are eliminated in the presence of A6R and only bilayer form factor peaks are observed. All of these observations point to the interaction of A6R with DPPC bilayers. These studies provide insight into interactions between a model cationic peptide and vesicles, relevant to understanding the action of antimicrobial peptides on lipid membranes. Notably, peptide A6R exhibits antimicrobial activity without membrane lysis.
authors.affiliation: School of Chemistry, Pharmacy and Food Biosciences, University of Reading , Whiteknights, Reading, RG6 6AD, United Kingdom.
authors.forename: Ashkan
authors.initials: A
authors.lastname: Dehsorkhi
authors.forename: Valeria
authors.initials: V
authors.lastname: Castelletto
authors.forename: Ian W
authors.initials: IW
authors.lastname: Hamley
authors.forename: Jani
authors.initials: J
authors.lastname: Seitsonen
authors.forename: Janne
authors.initials: J
authors.lastname: Ruokolainen
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology*; D019453:Escherichia coli O157 / Q000187:drug effects; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D009842:Oligopeptides; D013501:Surface-Active Agents; D015060:1,2-Dipalmitoylphosphatidylcholine