The biosynthetic origin of the pyridone ring of efrotomycin.
Nocardia lactamdurans has been shown to catabolyse uracil via the reductive pathway. The end product of this pathway, beta-alanine, is incorporated into the pyridone ring of efrotomycin. Support for this proposal includes: (1) reversal of thymine inhibition of efrotomycin biosynthesis by dihydrouracil and N-carbamoyl-beta-aline, two intermediates of the catabolic pathway; (2) incorporation of [5,6-3H]-uracil into efrotomycin with a relative molar specific activity of approximately 0.5, close to the theoretical maximum; and (3) 13C coupling at C4 and C5 of efrotomycin after feeding resting cells with [4,5-13C]-uracil. Our results do not rule out the possibility of an alternative source of beta-alanine or the coexistence of uracil catabolism via oxidative reactions.
Darland
G
G
Merck Sharp and Dohme Research Laboratories, Rahway, New Jersey 07065.
Arison
B
B
Kaplan
L
L
D000900:Anti-Bacterial Agents / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000737:chemistry; D005285:Fermentation; D015394:Molecular Structure; D016296:Mutagenesis; D009615:Nocardia / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D011728:Pyridones / Q000037:antagonists & inhibitors / Q000737:chemistry; D013936:Thymidine / Q000494:pharmacology; D013941:Thymine / Q000494:pharmacology; D014498:Uracil / Q000037:antagonists & inhibitors / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D011728:Pyridones; D014498:Uracil; C012954:efrotomycin; D013941:Thymine; D013936:Thymidine