title: Thiazorifamycins. III. Biosynthesis of rifamycins P, Q and verde, novel metabolites from a mutant of Nocardia mediterranea.
abstract: The thiazorifamycins are derived from rifamycin S and cysteine; rifamycins P and Verde are formed by chemical reactions, while rifamycin Q synthesis involves obligatory enzymatic assistance. All antibiotics come from a common six-member precursor lacking C-1 of cysteine; the thiazin-2-one ring of rifamycin Verde retains both C-2 and C-3 of cysteine, while the thiazole ring of rifamycins P and Q retains only C-2, C-3 becoming exocyclic in the ring-contraction C-3 is present in rifamycin Q but not in P.
mesh_terms: D001711:Biotransformation; D055598:Chemical Phenomena; D002621:Chemistry; D009154:Mutation; D009615:Nocardia / Q000235:genetics / Q000378:metabolism*; D012294:Rifamycins / Q000096:biosynthesis*
chemical_list: D012294:Rifamycins; C027407:rifamycin P; C027408:rifamycin Q; C027409:rifamycin Verde