Mechanism of membrane permeabilization by sticholysin I, a cytolysin isolated from the venom of the sea anemone Stichodactyla helianthus

The interaction of Stichodactyla helianthus sticholysin I (St-1) with lipid bilayers was investigated to elucidate the mechanism of the formation of oligomeric pores in host plasma membrane by actinaria cytolysins. Results were consistent with the model that the release of toxins occurs through a trimeric pore. With other actinoporins, a power dependence of the permeabilizing effects on the toxin concentration between 3 and 4 was observed leading to the proposal that the pore might be a tetrameric aggregate.