Ranatuerin 1T:: an antimicrobial peptide isolated from the skin of the frog, Rana temporaria

A peptide, termed ranatuerin 1T, with growth-inhibiting activity toward Staphylococcus aureus, was isolated from an extract of the skin of the European brown frog, Rana temporaria. The primary structure of the peptide was established as: GLLSGLKKVG(10) KHVAKNVAVS(20)LMDSLKCKIS(30)GDC. In common with other anti-microbial peptides from Ranid frogs, (e.g., ranalexin, ranatuerins, gaegurins, brevinins, esculetins, rugosins), ranatuerin 1T contains an intramolecular disulfide bridge forming a heptapeptide ring but there is little structural similarity outside this cyclic region. The minimum inhibitory concentration (MTC) of ranatuerin 1T was 120 mu M against the Gram-positive bacterium S. aureus and 40 mu M against the Gram-negative bacterium Escherichia coli, but the peptide was not active against the yeast Candida albicans. (C) 1999 Elsevier Science Inc. All rights reserved.