Kassinatuerin-1: A peptide with broad-spectrum antimicrobial activity isolated from the skin of the hyperoliid frog, Kassina senegalensis

Kassinatuerin-1 (GFMKYIGPLI(10)PHAVKAISDL(20)I.NH2) was isolated in high yi eld (75 nmol/g) from an extract of the skin of a Hyperoliid frog, the Afric an running frog Kassina senegalensis and its sequence was confirmed by tota l synthesis. The peptide inhibited growth of the gram-negative bacterium Es cherichia coli (minimum inhibitory concentration, MIC = 4 mu M), the gram-p ositive bacterium Staphylococcus aureus (MIC = 8 mu M), and the yeast Candi da albicans (MIC = 70 mu M). A structurally related peptide, kassinatuerin- 2 (FIQYLAPLI(10)PHAVKAISDL(20)I.NH2) was also isolated in high yield (96 nm ol/g) from the extract but was devoid of antimicrobial activity against the se microrganisms. Kassinatuerin-1 may be classified with other linear, cati onic antimicrobial peptides that can potentially adopt an amphipathic alpha -helical conformation but it contains almost no amino acid sequence identit y with previously characterized bioactive peptides from frog skin. (C) 2000 Academic Press.