Three-dimensional structure of a pyridoxal-phosphate-dependent enzyme, mitochondrial aspartate aminotransferase.

X-ray diffraction studies to 2.8-A resolution have yielded the three-dimensional structure of mitochondrial aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1), an isologous alpha 2 dimer (Mr = 2 x 45,000). The subunits are rich in secondary structure and contain two domains, one of which anchors the coenzyme, pyridoxal 5'-phosphate. Each active site lies between the subunits and is composed of residues from both of them.