title: Parallel and antiparallel dimers of magainin 2: their interaction with phospholipid membrane and antibacterial activity.
abstract: Magainin 2 (M2) forms pores by associating with several other M2 molecules in lipid membranes and shows antibacterial activity. To examine the effect of M2 dimerization on biological activity and membrane interaction, parallel and antiparallel M2 dimers were prepared from two monomeric precursors. Antibacterial and haemolytic activities were enhanced by dimerization. CD measurements showed that both dimers and monomers have an alpha-helical structure in the presence of lipid vesicles. Tryptophan fluorescence shift and KI quenching studies showed that all the peptides were more deeply embedded in acidic liposomes than in neutral liposomes. Experiments on dye-leakage activity and membrane translocation of peptides suggest that dimers and monomers form pores through lipid membranes, although the pore formation may be accompanied by membrane disturbance. Although dimerization of M2 increased the interaction activity with lipid membranes, no appreciable difference between the activities of parallel and antiparallel M2 dimers was observed.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, Nagasaki 852-8521, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Mukai
authors.forename: Yuko
authors.initials: Y
authors.lastname: Matsushita
authors.forename: Takuro
authors.initials: T
authors.lastname: Niidome
authors.forename: Tomomitsu
authors.initials: T
authors.lastname: Hatekeyama
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Aoyag
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002463:Cell Membrane Permeability; D002942:Circular Dichroism; D019281:Dimerization; D054806:Magainins; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000378:metabolism*; D021381:Protein Transport; D013050:Spectrometry, Fluorescence; D029867:Xenopus Proteins
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054806:Magainins; D010743:Phospholipids; D029867:Xenopus Proteins; C053301:magainin 2 peptide, Xenopus