Download MendeleyThree-dimensional structure of Escherichia coli branched-chain amino acid aminotransferase at 2.5 A resolution.
Okada, K., Hirotsu, K., Sato, M., Hayashi, H., Kagamiyama, H.(1997) J Biochem 121: 637-641
- PubMed: 9163511
- DOI: https://doi.org/10.1093/oxfordjournals.jbchem.a021633
- Primary Citation of Related Structures:
1A3G - PubMed Abstract:
The X-ray crystallographic structure of the branched-chain amino acid aminotransferase from Escherichia coli was determined by means of isomorphous replacement using the selenomethionyl enzyme as one of the heavy atom derivatives. The enzyme is a homo hexamer with D3 symmetry, and the polypeptide chain of the subunit is folded into two domains (small and large domains). The coenzyme, pyridoxal 5'-phosphate, resides at the domain interface, its re-face facing toward the protein. The active site structure shows that the following sites can recognize branched-chain amino acids and glutamate as substrates: (1) a hydrophobic core formed by Phe36, Tyr164, Tyr31*, and Val109* for a branched-chain; (2) Arg97 for an acidic side chain of glutamate; and (3) Tyr95 and two main chain NH groups of Thr257 and Ala258 for the alpha-carboxylate of substrates. Although the main chain conformation of the active site is homologous to that of D-amino acid aminotransferase, many of the active site residues are different between them.
Organizational Affiliation:
Department of Chemistry, Faculty of Science, Osaka City University, Sumiyoshi-ku, Osaka.
