Purification and characterization of novel antimicrobial peptides from the skin secretion of Hylarana guentheri

Linear, amphipathic and cationic antimicrobial peptides have been previously reported from a wide range of amphibian species especially frogs of the genus Rana. Such antimicrobial peptides are attracting increasing attention in pharmacological applications because they mainly act by permeabilizing and disrupting the target cell or virion membranes with a low degree of resistance. The Guenther's frog, Hylarana guentheri, is a Chinese frog of the genus Rana that is widely distributed in Southern China. It is commonly the dominant amphibian species even where the amphibian population is declining. In this study, we describe the isolation, purification, structural and biological characterization of five novel peptides from H. guentheri frog skin secretions that possess antimicrobial activity, including brevinin-2GHa, brevinin-2GHb, brevinin-2GHc, temporin-GH and a novel antimicrobial peptide named guentherin. The cDNAs encoding two novel members of the brevinin-2 family, brevinin-2GHb and brevinin-2GHc were also subsequently cloned and sequenced.