Mechanism of Initial Stage of Pore Formation by Antimicrobial Peptide Magainin 2

Antimicrobial peptides (AMPs) are a diverse class of naturally occurring molecules that are produced as a first line of defense by all multicellular organisms and can fight against bacteria, yeasts, fungi, viruses and even cancer cells. Magainin 2, which is isolated from the skin of frogs, is a representative AMP. Magainin 2, forms pores in lipid membranes and induces membrane permeation of the cellular contents. Although this permeation is likely the main cause of its bactericidal activity, the mechanism of pore formation remains poorly understood. Recent data suggest that binding of magainin 2 (at initial stage) to the outer monolayer of lipid bilayer induces tension or stretching in the inner monolayer that plays an important role in pore formation. To confirm the mechanism of magainin 2-induced pore formation at initial stage, I prepared asymmetrically packed giant unilameller vesicles, GUVs (diameter > 10 m), where inner monolayer is highly packed (less stretched) than outer one. Then the interaction of magainin 2 with these GUVs were investigated by single GUV method.