Download MendeleyStructural Insight into Concerted Inhibition of alpha(2)beta(2)-Type Aspartate Kinase from Corynebacterium glutamicum
Yoshida, A., Tomita, T., Kurihara, T., Fushinobu, S., Kuzuyama, T., Nishiyama, M.(2007) J Mol Biol 368: 521-536
- PubMed: 17350037
- DOI: https://doi.org/10.1016/j.jmb.2007.02.017
- Primary Citation of Related Structures:
2DTJ - PubMed Abstract:
Aspartate kinase (AK) catalyzes the first step of the biosynthesis of the aspartic acid family amino acids, and is regulated via feedback inhibition by end-products including Thr and Lys. To elucidate the mechanism of this inhibition, we determined the crystal structure of the regulatory subunit of AK from Corynebacterium glutamicum at 1.58 A resolution in the Thr-binding form, the first crystal structure of the regulatory subunit of alpha(2)beta(2)-type AK. The regulatory subunit contains two ACT domain motifs per monomer and is arranged as a dimer. Two non-equivalent ACT domains from different chains form an effector-binding unit that binds a single Thr molecule, and the resulting two effector-binding units of the dimer associate perpendicularly in a face-to-face manner. The regulatory subunit is a monomer in the absence of Thr but becomes a dimer by adding Thr. The dimerization is eliminated in mutant AKs with changes in the Thr-binding region, suggesting that the dimerization induced by Thr binding is a key step in the inhibitory mechanism of AK from C. glutamicum. A putative Lys-binding site and the inhibitory mechanism of CgAK are discussed.
Organizational Affiliation:
Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
