Magainin II is a member of the antimicrobial peptides family

Magainin 2 exhibits bactericidal activity by permeabilizing cell membranes and inducing early apoptosis-like morphological changes in Escherichia coli. It enhances the expression of a bacterial protein with caspase substrate affinity and modulates RecA expression, akin to caspase-like proteins. Notably, it disrupts membranes without significant harm to mammalian cells, targeting primarily the lipid matrix. In Paramecium caudatum, a protozoan, magainin 2 at 10 μg/mL induces osmotic swelling and cell burst by interfering with membrane functions crucial for osmotic regulation. Its mechanism differs in bacterial and mammalian cells; it forms approximately 2.8 nm pores in B. megaterium membranes and crosses into the cytosol, whereas in CHO-K1 cells, it causes significant membrane disturbance, allowing entry of molecules larger than 23 nm, and results in membrane budding and lipid redistribution, notably affecting mitochondria and nuclei.