[Study of channel-forming properties of latrotoxin in liposomes]

Interaction of latrotoxin with phospholipid vesicles and bilayer lipid membranes is shown to proceed differently. Latrotoxin when interacting with liposomes is sorbed on the membrane surface forming no ionic channels in this case. Only latrotoxin fragments obtained due to the toxin hydrolysis by pronase or trypsin are able to form channels. These fragments being inserted into liposomes are coupled strongly with the membrane and are not subjected to the further splitting by proteinases. The electrophoretic spectrum of peptides bound with liposomes is presented by protein components with a molecular weight of 116, 100, 92, 67, 52 and 45 kDa, while zone typical of latrotoxin is absent in this spectrum. The method of small-angle X-rays scattering has shown that tryptic fragments of latrotoxin penetrate into the phospholipid bilayer of liposomes.