title: Transbilayer transport of ions and lipids coupled with mastoparan X translocation.
abstract: The transbilayer movement of ions and lipids induced by mastoparan X, a peptidic toxin from Vespa xanthoptera, was investigated by use of lipid vesicles as a model membrane system. Negatively charged phosphatidylglycerol remarkably enhanced the peptide-lipid interactions. Mastoparan X induced the ion flow by forming a short-lived, multimeric pore in the lipid bilayer, as determined from the leakage of an anionic dye, calcein, from the liposomes. The pore formation was coupled with the translocation of the peptide into the inner leaflet. The latter was detected by three experiments using fluorescence techniques [Matsuzaki, K., Murase, O., Fujii, N., & Miyajima, K. (1995) Biochemistry 34, 6521-6526; Matsuzaki, K., Murase, O., & Miyajima, K. (1995) Biochemistry 34, 12553-12559]. The lipid flip flop was monitored on the basis of the chemical quenching of 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-labeled lipids by sodium dithionite. Mastoparan X triggered the rapid flip-flop of both negatively charged and zwitterionic lipids in coupling with the pore formation and the peptide translocation. A novel model of the mastoparan-lipid interactions was proposed to explain these observations.
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: S
authors.initials: S
authors.lastname: Yoneyama
authors.forename: O
authors.initials: O
authors.lastname: Murase
authors.forename: K
authors.initials: K
authors.lastname: Miyajima
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives / Q000378:metabolism; D000595:Amino Acid Sequence; D001692:Biological Transport / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D007477:Ions; D008051:Lipid Bilayers / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D010539:Permeability / Q000187:drug effects; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D014862:Wasp Venoms / Q000378:metabolism* / Q000494:pharmacology
chemical_list: C078632:1-acyl-2-(12-((7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoyl)phosphatidylcholine; D005452:Fluoresceins; D005456:Fluorescent Dyes; D036341:Intercellular Signaling Peptides and Proteins; D007477:Ions; D008051:Lipid Bilayers; D010455:Peptides; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D014862:Wasp Venoms; C042077:N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)phosphatidylethanolamine; C071123:mastoparan X; D009327:4-Chloro-7-nitrobenzofurazan; C007740:fluorexon