title: Bilayer localization of membrane-active peptides studied in biomimetic vesicles by visible and fluorescence spectroscopies.
abstract: Depth of bilayer penetration and effects on lipid mobility conferred by the membrane-active peptides magainin, melittin, and a hydrophobic helical sequence KKA(LA)7KK (denoted KAL), were investigated by colorimetric and time-resolved fluorescence techniques in biomimetic phospholipid/poly(diacetylene) vesicles. The experiments demonstrated that the extent of bilayer permeation and peptide localization within the membrane was dependent upon the bilayer composition, and that distinct dynamic modifications were induced by each peptide within the head-group environment of the phospholipids. Solvent relaxation, fluorescence correlation spectroscopy and fluorescence quenching analyses, employing probes at different locations within the bilayer, showed that magainin and melittin inserted close to the glycerol residues in bilayers incorporating negatively charged phospholipids, but predominant association at the lipid-water interface occurred in bilayers containing zwitterionic phospholipids. The fluorescence and colorimetric analyses also exposed the different permeation properties and distinct dynamic influence of the peptides: magainin exhibited the most pronounced interfacial attachment onto the vesicles, melittin penetrated more into the bilayers, while the KAL peptide inserted deepest into the hydrophobic core of the lipid assemblies. The solvent relaxation results suggest that decreasing the lipid fluidity might be an important initial factor contributing to the membrane activity of antimicrobial peptides.
authors: Department of Chemistry and the Stadler Minerva Center for Mesoscopic Macromolecular Engineering, Ben Gurion University of the Negev, Beersheva, Israel.
authors: Tanya
authors: T
authors: Sheynis
authors: Jan
authors: J
authors: Sykora
authors: Ales
authors: A
authors: Benda
authors: Sofiya
authors: S
authors: Kolusheva
authors: Martin
authors: M
authors: Hof
authors: Raz
authors: R
authors: Jelinek
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D040761:Biomimetic Materials / Q000737:chemistry / Q000378:metabolism; D003124:Colorimetry; D004305:Dose-Response Relationship, Drug; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism*; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D054806:Magainins; D008555:Melitten / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D029867:Xenopus Proteins
chemical_list: D023181:Antimicrobial Cationic Peptides; D008051:Lipid Bilayers; D008081:Liposomes; D054806:Magainins; D008565:Membrane Proteins; D029867:Xenopus Proteins; C053301:magainin 2 peptide, Xenopus; D008555:Melitten