title: Antibiotics A21459 A and B, new inhibitors of bacterial protein synthesis. II. Structure elucidation.
abstract: 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 alpha-aminobutyric acid for A21459 A (alanine for A21459 B). Cysteine and alanine condensed to form a thiazole moiety, according to the biosynthesis of thiazole containing antibiotics.
authors.affiliation: Marion Merrell Dow Research Institute, Lepetit Research Center, Gerenzano (VA), Italy.
authors.forename: P
authors.initials: P
authors.lastname: Ferrari
authors.forename: K
authors.initials: K
authors.lastname: Vékey
authors.forename: M
authors.initials: M
authors.lastname: Galimberti
authors.forename: G G
authors.initials: GG
authors.lastname: Gallo
authors.forename: E
authors.initials: E
authors.lastname: Selva
authors.forename: L F
authors.initials: LF
authors.lastname: Zerilli
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000737:chemistry / Q000494:pharmacology; D013057:Spectrum Analysis
chemical_list: C099219:A21459 A; C099220:A21459 B; D000596:Amino Acids; D000900:Anti-Bacterial Agents; D010456:Peptides, Cyclic