Conformation of membrane fusion-active 20-residue peptides with or without lipid bilayers. Implication of alpha-helix formation for membrane fusion.
Fusion of small unilamellar vesicles of egg phosphatidylcholine can be triggered with synthetic 20-residue peptides. Taking the N-terminal amino acid sequence of HA-2 polypeptide of influenza virus as a guideline, we designed and synthesized several peptides having amphiphilic structures. Among the peptides so far studied, those active to induce membrane fusion took an alpha-helical conformation in the presence of phospholipid bilayers, while a peptide which was unable to induce membrane fusion was in a beta-structure. Mixing of a pair of positively and negatively charged peptides, which had a complementary arrangement of electric charges to each other, resulted in alpha-helix formation at neutral pH, the condition of forming a randomly coiled conformation for each peptide. We concluded that alpha-helix formation was one of the necessary conditions to trigger a process of membrane fusion, at least in the present set of peptides. Characteristic features of these amphiphilic peptides are also described.
Institute for Chemical Research, Kyoto University, Japan.
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Takahashi
D000595:Amino Acid Sequence; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000494:pharmacology*; D008051:Lipid Bilayers; D008561:Membrane Fusion / Q000187:drug effects*; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000494:pharmacology*; D010713:Phosphatidylcholines; D013329:Structure-Activity Relationship
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D008051:Lipid Bilayers; D010446:Peptide Fragments; D010713:Phosphatidylcholines