Kurstakins: A new class of lipopeptides isolated from Bacillus thuringiensis

A novel class of Lipopeptides was isolated from Bacillus thuringiensis kurs taki HD-1. Four compounds (1-4) were separated by high-performance liquid c hromatography and their primary structures determined using a combination o f chemical reactions and mass spectrometry. The four Lipopeptides were foun d to have the same amino acid sequence, Thr-Gly-Ala-Ser-His-Gln-Gln, but di fferent fatty acids. The fatty acyl chain is linked to the N-terminal amino acid residue via an amide bond. Each lipopeptide has a lactone linkage bet ween the carboxyl terminal amino acid and the hydroxyl group in the side ch ain of the serine residue. Antifungal activity was demonstrated against Sta chybotrys charatum.