NOVEL ANTIMICROBIAL PEPTIDES FROM SKIN SECRETION OF THE EUROPEAN FROGRANA-ESCULENTA

Three antimicrobial peptides were isolated from skin secretion of the European frog, Rana esculenta. Two of them show similarity to brevinin -1 and brevinin-2, respectively, two antimicrobial peptides recently i solated from a Japanese frog [Morikawa, N., Hagiwara, K. and Nakajima, T. (1992) Biochem. Biophys. Res. Commun. 189, 184-1901. The third one , named esculentin, is 46 residues long and represents a different typ e of peptide. All these peptides have as a common motif an intramolecu lar disulfide bridge located at the COOH-terminal end. The peptides fr om R. esculenta show distinctive antibacterial activity against repres entative Gram-negative and Gram-positive bacterial species. In particu lar, esculentin is the most active against Staphylococcus aureus, and has a much lower hemolytic activity.