文摘
The biosynthesis of 4-hydroxy-3-nitrosobenzamide inStreptomyces murayamaensis mutants MC2andMC3 has been studied using sodium [1,2-13C2]-and [1-13C,18O2]acetate,sodium [2,3-13C2]succinate,[1,2-13C2]glutamicacid, [4-13C]aspartic acid, and sodium[1-13C]- and[2,3-13C2]pyruvate. 13CNMR analysis of the labeling patternsfrom the first two of these suggested a pathway via condensation of afour-carbon unit from the tricarboxylic acid(TCA) cycle with a three-carbon unit, possibly phosphoenol pyruvate.Subsequent specific incorporations of thelabeled succinic acid, aspartic acid, and glutamic acid confirmed theTCA cycle involvement and the orientation ofthe four-carbon intermediate. Specific incorporation of thelabeled pyruvic acids confirmed the involvement of athree-carbon unit and defined its orientation. This is the firstaminohydroxybenzoic acid derivative shown not to bederived from a shikimic acid-type pathway, and its origin provides arationale for the biosynthesis of other microbialproducts such as asukamycin, manumycin, and themichigazones.