4je5
Crystal structure of the aromatic aminotransferase Aro8, a putative alpha-aminoadipate aminotransferase in Saccharomyces cerevisiae
Structural highlights
FunctionARO8_YEAST General aromatic amino acid transaminase involved in several otherwise unrelated metabolic pathways. Responsible for phenylalanine and tyrosine biosynthesis. Active with glutamate, phenylalanine, tyrosine and tryptophan as amino donors and with phenylpyruvate, hydroxyphenylpyruvate, 2-oxoglutarate and pyruvate as amino acceptors. Also active with methionine, alpha-aminoadipate and leucine as amino donors when phenylpyruvate is the amino acceptor and in the reverse reactions with the corresponding oxo acids and phenylalanine as amino donor. Catalyzes the formation of methionine from 2-keto-4-methylthiobutyrate (KMTB) in the methionine salvage pathway primarily using aromatic amino acids (tyrosine, phenylalanine and tryptophan) as the amino donors. Catalyzes the formation of alpha-aminoadipate from alpha-ketoadipate in the lysine biosyntheic pathway.[1] [2] [3] [4] [5] Publication Abstract from PubMedalpha-Aminoadipate aminotransferase (AAA-AT) catalyzes the amination of 2-oxoadipate to alpha-aminoadipate in the fourth step of the alpha-aminoadipate pathway of lysine biosynthesis in fungi. The aromatic aminotransferase Aro8 has recently been identified as an AAA-AT in Saccharomyces cerevisiae. This enzyme displays broad substrate selectivity, utilizing several amino acids and 2-oxo acids as substrates. Here we report the 1.91A resolution crystal structure of Aro8 and compare it to AAA-AT LysN from Thermus thermophilus and human kynurenine aminotransferase II. Inspection of the active site of Aro8 reveals asymmetric cofactor binding with lysine-pyridoxal-5-phosphate bound within the active site of one subunit in the Aro8 homodimer and pyridoxamine phosphate and a HEPES molecule bound to the other subunit. The HEPES buffer molecule binds within the substrate-binding site of Aro8, yielding insights into the mechanism by which it recognizes multiple substrates and how this recognition differs from other AAA-AT/kynurenine aminotransferases. Crystal structure of Saccharomyces cerevisiae Aro8, a putative alpha-aminoadipate aminotransferase.,Bulfer SL, Brunzelle JS, Trievel RC Protein Sci. 2013 Jul 24. doi: 10.1002/pro.2315. PMID:23893908[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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