3pdb
Crystal structure of mouse mitochondrial aspartate aminotransferase in complex with oxaloacetic acid
Structural highlights
FunctionAATM_MOUSE Catalyzes the irreversible transamination of the L-tryptophan metabolite L-kynurenine to form kynurenic acid (KA). Plays a key role in amino acid metabolism. Important for metabolite exchange between mitochondria and cytosol. Facilitates cellular uptake of long-chain free fatty acids.[1] [2] Publication Abstract from PubMedMammalian mitochondrial aspartate aminotransferase (mAspAT) is recently reported to have kynurenine aminotransferase (KAT) activity and plays a role in the biosynthesis of kynurenic acid (KYNA) in rat, mouse and human brains. This study concerns the biochemical and structural characterization of mouse mAspAT. In this study, mouse mAspAT cDNA was amplified from mouse brain first stand cDNA and its recombinant protein was expressed in an Escherichia coli expression system. Sixteen keto acids were tested for the co-substrate specificity of mouse mAspAT and fourteen of them were shown to be capable of serving as co-substrates for the enzyme. Structural analysis of mAspAT by macromolecular crystallography revealed that the cofactor binding residues of mAspAT are similar to those of other KATs. The substrate binding residues of mAspAT are slightly different from those of other KATs. Our data provide a biochemical and structural basis towards understanding the overall physiological role of mAspAT in vivo and insight into controlling the levels of endogenous KYNA through modulation of the enzyme in the mouse brain. Biochemical and structural characterization of mouse mitochondrial aspartate aminotransferase, a newly identified kynurenine aminotransferase-IV.,Han Q, Robinson H, Cai T, Tagle DA, Li J Biosci Rep. 2010 Oct 26. PMID:20977429[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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