A synthetic peptide corresponding to the hydrophobic amino terminal region of pardaxin can perturb model membranes of phosphatidyl choline and serine

Abstract

Peptides corresponding to the amino terminal region of pardaxin from Pardachirus pavoninus (Gly---Phe---Phe---Ala---Leu---Ile---Pro---Lys---Ile---Ile---Ser---Ser---Pro---Leu ---Phe) have been synthesized and their interaction with model membranes of phosphatidyl choline and serine studied by 90°C light scattering and fluorescence spectroscopy. The amino terminal 8-residue peptide and the protected 15-residue peptide cause only aggregation of lipid vesicles. The deprotected 15-residue peptide has the ability to cause aggregation and release of entrapped carboxyfluorescein with both phosphatidyl choline and serine lipid vesicles, like pardaxin. The membrane-perturbing ability of the amino terminal 15-residue peptide can be attributed to its ability to adopt an a-helical conformation which is amphiphilic in nature in a hydrophobic environment.