title: An antimicrobial peptide, magainin 2, induced rapid flip-flop of phospholipids coupled with pore formation and peptide translocation.
abstract: The effect of an antimicrobial peptide, magainin 2, on the flip-flop rates of phospholipids was investigated by use of fluorescent lipids, i.e., anionic N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)dipalmitoyl-L-alpha- phosphatidylethanolamine (NBD-PE), 1-oleoyl-2-[12-((7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)- dodecanoyl]-L-alpha-phosphatidic acid (C12-NBD-PA), 1-oleoyl-2-[12- ((7-nitrobenz-2-oxa-1,3-diazol-4-yl)- amino)dodecanoyl]-L-alpha-phosphatidyl-L-serine (C12-NBD-PS), and zwitterionic 1-palmitoyl-2-[6-((7- nitrobenz-2-oxa-1,3-diazol-4-yl)amino)caproyl]-L-alpha-phosphatidy lcholine (C6-NBD-PC). Their intrinsic flip-flop half-lives at 30 degrees C in the absence of the peptide were 1.1 h, ca. 7 h, ca. 8 days, and > 2 days, respectively. The peptide accelerated the flip-flop half-lives of the fluorescent lipids to an order of minutes. Furthermore, the flip-flop was coupled with the membrane permeabilization and the peptide translocation [Matsuzaki, K., Murase, O., Fujii, N., & Miyajima, K. (1995) Biochemistry 34, 6521-6526], suggesting pore-mediated flip-flop. The flip-flop rate was independent of the initial labeling conditions (outer leaflet label or inner leaflet label). From these results, a model was proposed, in which the lipids translocate across the membrane by lateral diffusion along the wall of the pores composed of the peptides and the lipids. A simple theoretical calculation could explain the coupling of the flip-flop with the permeabilization.
authors.affiliation: Faculty of Pharmaceutical Sciences, Kyoto University, Japan. katsumim@pharmsun.pharm.kyoto-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Matsuzaki
authors.forename: O
authors.initials: O
authors.lastname: Murase
authors.forename: N
authors.initials: N
authors.lastname: Fujii
authors.forename: K
authors.initials: K
authors.lastname: Miyajima
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D004058:Diffusion; D004227:Dithionite / Q000378:metabolism; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D007700:Kinetics; D008051:Lipid Bilayers / Q000378:metabolism*; D008081:Liposomes / Q000378:metabolism; D054806:Magainins; D008433:Mathematics; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D010539:Permeability / Q000187:drug effects; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D012867:Skin / Q000737:chemistry; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D005452:Fluoresceins; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D008081:Liposomes; D054806:Magainins; D010455:Peptides; D010714:Phosphatidylethanolamines; D010743:Phospholipids; D029867:Xenopus Proteins; C053301:magainin 2 peptide, Xenopus; D004227:Dithionite; C042077:N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)phosphatidylethanolamine; C007740:fluorexon