Crystal structure of Saccharomyces cerevisiae Aro8, a putative [alpha]-aminoadipate aminotransferase

• Published in: Protein science Vol. 22; no. 10; pp. 1417 - 1424
• Main Authors: Bulfer, Stacie L, Brunzelle, Joseph S, Trievel, Raymond C
• Format: Journal Article
• Language: English
• Published: Bethesda Wiley Subscription Services, Inc 01-10-2013
• Subjects: Acids; Saccharomyces cerevisiae
• ISSN: 0961-8368; 1469-896X
• DOI: 10.1002/pro.2315

[alpha]-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 1.91Å 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. PDB Code(s): 4JE5 [PUBLICATION ABSTRACT]