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Biosynthesis of the modified peptide antibiotic nosiheptide in Streptomyces actuosus

Journal Article · · J. Am. Chem. Soc.; (United States)
DOI:https://doi.org/10.1021/ja00225a035· OSTI ID:6181056

The biosynthesis of the modified, sulfur-rich peptide antibiotic nosiheptide (1) was studied in feeding experiments with radioactive and /sup 13/C-labeled precursors in Streptomyces actuosus. Following extensive chemical-shift assignments, /sup 13/C-labeled samples of 1 were analyzed by /sup 13/C NMR spectroscopy. In addition to supporting the expected origin of the thiazole ring and the L-cysteine moiety from cysteine, the L-threonine and butyrine moieties from threonine, and the hydroxyglutamate moiety from glutamate, the results demonstrated that the dehydroalanine moiety arises by dehydration of serine. The pyridine ring is formed uniquely by tail-to-tail condensation of two serine residues. As demonstrated by a double-labeling experiment, the indolic acid moiety arises by a novel intramolecular rearrangement of tryptophan in which the carboxyl group is connected to C2 of the indole and the ..cap alpha..-carbon and the amino nitrogen are eliminated. Only the hydroxymethyl group at C4 of the indole ring is derived by a C-methylation, but not via 4-methyltryptophan. The results define the sequence of a hypothetical peptide precursor of 1. 34 references, 3 figures, 4 tables.

Research Organization:
Ohio State Univ., Columbus (USA)
OSTI ID:
6181056
Journal Information:
J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 110:17; ISSN JACSA
Country of Publication:
United States
Language:
English