Interaction of amphipathic model lipopeptides with phospholipid bilayers.
In order to investigate the conformation and localization of lipopeptides in lipid bilayers, a basic model peptide with a long alkyl chain, Ac-Ser-Val-Lys-Amy-Ser-Trp-Lys-Val-NHCH3 Amy-1; Amy = alpha-aminomyristic acid) was synthesized. Its interaction with neutral and acidic phospholipid bilayers was studied by circular dichroism (CD) spectroscopy, dye leakage and fluorescence measurements. Another peptide, Ac-Leu-Ala-Arg-Leu-Trp-Amy-Arg-Leu-Leu-Ala-Arg-Leu-NHCH3 (Amy-2), which was prepared previously, was used for comparison. The CD data indicated that Amy-1 took a beta-turn and/or a beta-structure in the absence and presence of liposomes. Amy-2 formed a beta-structure in aqueous solution and an alpha-helical structure in liposomes. The dye leakage ability of Amy-1 was much weaker than that of Amy-2. Fluorescence spectroscopic data suggest that the peptides are immersed in lipid bilayers. Based on these results, discussion is made in terms of localization of the peptides in lipid bilayers.
Ono
S
S
Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan.
Kato
T
T
Lee
S
S
Aoyagi
H
H
Ohno
M
M
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D008074:Lipoproteins / Q000138:chemical synthesis / Q000737:chemistry*; D008081:Liposomes; D008567:Membranes, Artificial; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence
D008074:Lipoproteins; D008081:Liposomes; D008567:Membranes, Artificial; D010455:Peptides; D010743:Phospholipids