CHANGE IN MEMBRANE-PERMEABILITY INDUCED BY PROTEGRIN-1 - IMPLICATION OF DISULFIDE BRIDGES FOR PORE FORMATION

Protegrin 1 (PG-1) is a naturally occurring cationic antimicrobial pep tide that is 18 residues long, has an aminated carboxy terminus and co ntains two disulphide bridges. Here, we investigated the antimicrobial activity of PG-1 and three linear analogues. Then, the membrane perme abilisation induced by these peptides was studied upon Xenopus laevis oocytes by electrophysiological methods. From the results obtained, we concluded that protegrin is able to form anion channels. Moreover, it seems clear that the presence of disulphide bridges is a prerequisite for the pore formation at the membrane level and not for the antimicr obial activity.