title: The interactions of antimicrobial peptides derived from lysozyme with model membrane systems.
abstract: Two peptides, RAWVAWR-NH2 and IVSDGNGMNAWVAWR-NH2, derived from human and chicken lysozyme, respectively, exhibit antimicrobial activity. A comparison between the L-RAWVAWR, D-RAWVAWR, and the longer peptide has been carried out in membrane mimetic conditions to better understand how their interaction with lipid and detergent systems relates to the reported higher activity for the all L-peptide. Using CD and 2D 1H NMR spectroscopy, the structures were studied with DPC and SDS micelles. Fluorescence spectroscopy was used to study peptide interactions with POPC and POPG vesicles and DOPC, DOPE, and DOPG mixed vesicle systems. Membrane-peptide interactions were also probed by ITC and DSC. The ability of fluorescein-labeled RAWVAWR to rapidly enter both E. coli and Staphylococcus aureus was visualized using confocal microscopy. Reflecting the bactericidal activity, the long peptide interacted very weakly with the lipids. The RAWVAWR-NH2 peptides preferred lipids with negatively charged headgroups and interacted predominantly in the solvent-lipid interface, causing significant perturbation of membrane mimetics containing PG headgroups. Peptide structures determined by 1H NMR indicated a well-ordered coiled structure for the short peptides and the C-terminus of the longer peptide. Using each technique, the two enantiomers of RAWVAWR-NH2 interacted in an identical fashion with the lipids, indicating that any difference in activity in vivo is limited to interactions not involving the membrane lipids.
authors.affiliation: Structural Biology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
authors.forename: Howard N
authors.initials: HN
authors.lastname: Hunter
authors.forename: Weiguo
authors.initials: W
authors.lastname: Jing
authors.forename: David J
authors.initials: DJ
authors.lastname: Schibli
authors.forename: Tony
authors.initials: T
authors.lastname: Trinh
authors.forename: In Yup
authors.initials: IY
authors.lastname: Park
authors.forename: Sun Chang
authors.initials: SC
authors.lastname: Kim
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Vogel
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D040761:Biomimetic Materials / Q000737:chemistry; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002645:Chickens; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D008560:Membrane Fluidity; D009113:Muramidase / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D011485:Protein Binding; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D023181:Antimicrobial Cationic Peptides; D008051:Lipid Bilayers; D008081:Liposomes; D010743:Phospholipids; C421864:hen egg lysozyme; D009113:Muramidase