Atomic Force Microscopy and Electrochemical Studies of Melittin Action on Lipid Bilayers Supported on Gold Electrodes

摘要: ABSTRACT Melittin is an amphipathic helical peptide which shows strong membranolytic activity against bacterial cells as well human erythrocytes. It often considered a good model for general studies on interactions of antimicrobial peptides with biological membranes since the detailed mechanisms their action are still subject intense debate. In this paper we have used electrochemical methods combined in situ AFM imaging order to evaluate involved melittin activity. We observed that high concentration causes rapid degradation single component DMPC bilayer supported gold electrode. The lipid membrane undergoes micellization and subsequent dissolution. This indicates under such conditions acts according detergent-like mechanism. mode differs substantially when lowered. case, changes structure less at initial stages adsorbs top membrane. process followed by fluidization film, facilitates further reorientation insertion into bilayer. As result, permeability increased. data sharp differentiation between carpet toroidal pore mechanism difficult it very likely mixed Yet different behavior was DMPC/Cholesterol susceptibility reduced probably due increased packing within hydrocarbon chain region also noticed common feature all systems studied here. Thus, seems be crucial step enables molecules adopt proper orientation either formation or disruption