Softening of POPC membranes by magainin

Magainin 2 belongs to the family of peptides, which interacts with the lipid membranes. The present work deals with the effect of this peptide on the mechanical properties of 1-paimitoyl-2-oleoyl-sn-glycerol-3-phosphocholine Giant Unilamellar Vesicle, characterized by the bending stiffness modulus. The ber ding elastic modulus is measured by Vesicle Fluctuation Analysis at biologically relevant pH and physiological buffer conditions and shows a dramatic decrease with increasing peptide concentration. The observed bilayer softening is interpreted in terms of a continuum model describing perturbations on the membrane organization. Our analysis suggests that the adsorbed peptides give rise to considerable local curvature disruptions of the membrane. (c) 2008 Elsevier B.V. All rights reserved.