Three different classes of aminotransferases evolved prephenate aminotransferase functionality in arogenate-competent microorganisms [Enzymology]

December 3rd, 2013 by Graindorge, M., Giustini, C., Kraut, A., Moyet, L., Curien, G., Matringe, M.

The aromatic amino acids phenylalanine and tyrosine represent essential sources of high value natural aromatic compounds for human health and industry. Depending on the organism, alternative routes exist for their synthesis. Phenylalanine and tyrosine are synthesized either via phenylpyruvate/4-hydroxyphenylpyruvate, or via arogenate. In arogenate-competent microorganisms an aminotransferase is required for the transamination of prephenate into arogenate but the identity of the genes is still unknown. We present here the first identification of prephenate aminotransferases (PAT) in seven arogenate-competent microorganisms and the discovery that PAT activity is provided by three different classes of aminotransferase which belong to two different fold-types of PLP enzymes: an aspartate aminotransferase subgroup 1β in tested α- and β-proteobacteria, a branched-chain aminotransferase in tested cyanobacteria, and an N-succinyl-diaminopimelate amino-transferase in tested actinobacteria and in the β-proteobacterium Nitrosomonas europaea. Recombinant PAT enzymes exhibit high activity towards prephenate, indicating that the corresponding genes encode bona fide PAT. PAT functionality was acquired without other modification of substrate specificity, and is not a general catalytic property of the three classes of aminotransferases.
  • Posted in Journal of Biological Chemistry, Publications
  • Comments Off on Three different classes of aminotransferases evolved prephenate aminotransferase functionality in arogenate-competent microorganisms [Enzymology]