Download MendeleyMechanism of inactivation of Escherichia coli aspartate aminotransferase by (S)-4-amino-4,5-dihydro-2-furancarboxylic acid .
Liu, D., Pozharski, E., Fu, M., Silverman, R.B., Ringe, D.(2010) Biochemistry 49: 10507-10515
- PubMed: 21033689
- DOI: https://doi.org/10.1021/bi101325z
- Primary Citation of Related Structures:
3PA9, 3PAA - PubMed Abstract:
As a potential drug to treat neurological diseases, the mechanism-based inhibitor (S)-4-amino-4,5-dihydro-2-furancarboxylic acid (S-ADFA) has been found to inhibit the γ-aminobutyric acid aminotransferase (GABA-AT) reaction. To circumvent the difficulties in structural studies of a S-ADFA-enzyme complex using GABA-AT, l-aspartate aminotransferase (l-AspAT) from Escherichia coli was used as a model PLP-dependent enzyme. Crystal structures of the E. coli aspartate aminotransferase with S-ADFA bound to the active site were obtained via cocrystallization at pH 7.5 and 8. The complex structures suggest that S-ADFA inhibits the transamination reaction by forming adducts with the catalytic lysine 246 via a covalent bond while producing 1 equiv of pyridoxamine 5'-phosphate (PMP). Based on the structures, formation of the K246-S-ADFA adducts requires a specific initial binding configuration of S-ADFA in the l-AspAT active site, as well as deprotonation of the ε-amino group of lysine 246 after the formation of the quinonoid and/or ketimine intermediate in the overall inactivation reaction.
Organizational Affiliation:
Department of Biochemistry, Rosenstiel Basic Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts 02454-9110, United States.
