control of aromatic amino acid biosynthesis in an obligate methlotrophic bacterium Methylobacillus mucogenes M75

摘要

We studied control of biosynthesis of aromatic amino acids in obligate methylotrophic bacteria Methylobacillus mucogenes M75. control of the shikmate pathway occurs at the level of 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase due to retroinhibition of DAHPS-[Phe], DAHPS-[Tyr], and DAHPS-[Trp] isozymes by phenylalanine, tyrosine, and tryptophan respectively. Biosynthesis of tryptophan is controlled through repression of genes trpE, trpD, and trpC by tryptophan, as well as by retroinhibition of anthranilate-synthase. Regulation of synthesis of phenylalanine and tyrosine, as well as through retroinhibition of prephenate-dehydratase activity.