The structures of the antibiotics, active against a few Gram-negative bacteria and Clostridium difficile, were determined on the basis of physicochemical analyses on the intact molecules and on the acid hydrolysate of A21459 A. FAB-MS and 1H and 13C NMR investigations identified the amino acid units and determined their sequence. Antibiotics A21459 A and B are homodetic cyclic peptides constituted by eight amino acid units. They are glycine, methoxytryptophan, tryptophan, cysteine, alanine, sarcosine, dehydroalanine, and α-aminobutyric acid for A21459 A (alanine for A21459 B). Cysteine and alanine condensed to form a thiazole moiety, according to the biosymthesis of thiazole containing antibiotics.
ASJC Scopus subject areas
- Drug Discovery