Pyrrolo[1, 4]benzodiazepine Antibiotics. Biosynthesis of the Antitumor Antibiotic Sibiromycin by Streptosporangium sibiricum

The biosynthesis of the antitumor antibiotic sibiromycin by Streptosporangium sibiricum requires the construction of four units: the amino sugar from glucose; the anthranilate ring from dl-tryptophan probably via kynurenine; the aromatic methyl group from methionine; the propylidene proline from l-tyrosine with the loss of two aromatic carbons and addition of a C-l from methionine. Retention of tritium from dl-[5-3H]tryptophan in sibiromycin suggests an NIH shift during hydroxylation of an intermediate.