Synthesis of [l-α-Aminomyristic Acid3,3′]gramicidin S and Its Interaction with Phospholipid Bilayer

Abstract

Abstract A lipophilized gramicidin S (GS) analog was synthesized by introducing l-α-aminomyristic acid (Amy) residues instead of l-leucine residues by the conventional solution method. Influences of lipophilization of GS on interaction with phospholipid liposomes were examined by the peptide-induced dye-leakage assays using carboxyfluorescein (CF)-entrapped liposomes of dipalmitoyl-Dl-α-phosphatidylcholine (DPPC). The [Amy3,3′]GS (Amy-GS) had the enhanced ability of CF-leakage below the phase-transition temperature of DPPC liposomes as compared with GS, while it showed weaker leakage ability at higher temperature. Conformation of Amy-GS in solution and in the presence of liposomes was similar to that of GS, which was elucidated by CD and 1H NMR measurements. The Amy residue can be utilized to enhance the affinity of a peptide to membrane environment without changing conformation of an original peptide.