title: Interaction of bundled Ser-rich amphiphilic peptides with phospholipid membranes.
abstract: To investigate properties of hydrophilic bundled peptides and their interactions with phospholipid membranes, bundled peptides named [Trp2]- and [Trp12]-4alpha-46S9, which are composed of four fragments of amphiphilic 24-mer peptide, were designed and synthesized. Tryptophan (Trp) was introduced at the 2nd position from the N-terminal or at the centre (12th) of the helix to monitor the peptide-lipid interaction. Circular dichroism measurements indicated that the peptides had low alpha-helicities in a buffer solution (pH 7.4) and also in the presence of dipalmitoyl-DL-3-phosphatidylcholine (DPPC) vesicles. In the presence of DPPC/dipalmitoyl-DL-3-phosphatidylglycerol (DPPG) (3:1) vesicles, the measurement could not be taken because of turbidity induced by vesicle aggregation. Both peptides had moderate perturbation activity for both the neutral and acidic vesicles at 25 degrees C. The perturbation patterns at 50 degrees C were much different from those at 25 degrees C and the maximum activity reached 100% at a low peptide concentration. The results of the measurement of membrane fusion activity of peptides showed a similar tendency to that found in the perturbation experiment. A quenching experiment indicated that the Trp2 and Trp12 residues in [Trp2]- and [Trp12]-4alpha-46S9 were scarcely embedded in neutral lipid membranes.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: N
authors.initials: N
authors.lastname: Ohmori
authors.forename: Y
authors.initials: Y
authors.lastname: Mukai
authors.forename: T
authors.initials: T
authors.lastname: Niidome
authors.forename: T
authors.initials: T
authors.lastname: Hatakeyama
authors.forename: H
authors.initials: H
authors.lastname: Aoyagi
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D002942:Circular Dichroism; D008561:Membrane Fusion / Q000187:drug effects; D008567:Membranes, Artificial; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism*; D017433:Protein Structure, Secondary; D012694:Serine / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D008567:Membranes, Artificial; D010455:Peptides; D010743:Phospholipids; D012694:Serine