Electrostatically Controlled Interactions of Mouse Paneth Cell α-Defensins with Phospholipid Membranes

Antimicrobial peptides of the innate immune systems of many organisms are known to interact with lipid membranes, with electrostatic interactions playing an important role. We have studied the interactions of the mouse a-defensin, cryptdin-4, and its precursor, procryptdin-4, with phospholipid model membranes in the form of vesicles. Both peptides induce ‘graded’ leakage of vesicle contents, however procryptdin-4 exhibits only minimal membrane disruptive activity. Vesicles containing a higher fraction of anionic lipid are more susceptible to peptide-induced leakage. Electrophoretic mobility measurements at several vesicle compositions reveal a correlation between the surface potential of vesicles and the peptide-induced vesicle leakage.