Interaction of α‐helical peptides with phospholipid membrane: effects of chain length and hydrophobicity of peptides

Abstract

To investigate the interaction of amphiphilic α‐helical peptides with phospholipid membranes, we synthesized Ac‐(Leu‐Ala‐Arg‐Leu)₃‐NHcH₃ (4₃) and three derivatives, in which the chain length and the size of the hydrophobic region of the peptides were different from each other. These peptides formed an α‐helical structure in the presence of vesicles. In the membrane‐perturbation measurement, only 4₃ showed a strong membrane‐perturbation activity below phase‐transition temperature (25°C), but above phase‐transition temperature (50°C), most peptides showed similar strong activities. On the other hand, in membrane‐fusion measurement the long peptides, e.g., Ac‐(Leu‐Ala‐Arg‐Leu)₃‐(Leu‐Arg‐Ala‐Leu)₃‐NHCH₃, had strong activities at low peptide concentrations at 25°C. The present study indicated a parallel relationship did not always exist between membrane fusion and perturbation caused by peptides.