Download MendeleyThe Crystal Structure of Murine CMP-5-N-acetylneuraminic Acid Synthetase
Krapp, S., Muenster-Kuehnel, A.K., Kaiser, J.T., Huber, R., Tiralongo, J., Gerardy-Schahn, R., Jacob, U.(2003) J Mol Biol 334: 625-637
- PubMed: 14636592
- DOI: https://doi.org/10.1016/j.jmb.2003.09.080
- Primary Citation of Related Structures:
1QWJ - PubMed Abstract:
Sialic acids are activated by CMP-5-N-acetylneuraminic acid synthetase prior to their transfer onto oligo- or polysaccharides. Here, we present the crystal structure of the N-terminal catalytically active domain of the murine 5-N-acetylneuraminic acid synthetase in complex with the reaction product. In contrast to the previously solved structure of 5-N-acetylneuraminic acid synthetase from Neisseria meningitidis and the related CMP-KDO-synthetase of Escherichia coli, the murine enzyme is a tetramer, which was observed with the active sites closed. In this conformation a loop is shifted by 6A towards the active site and thus an essential arginine residue can participate in catalysis. Furthermore, a network of intermolecular salt-bridges and hydrogen bonds in the dimer as well as hydrophobic interfaces between two dimers indicate a cooperative behaviour of the enzyme. In addition, a complex regulation of the enzyme activity is proposed that includes phosphorylation and dephosphorylation.
Organizational Affiliation:
Max-Planck-Institut für Biochemie, Abteilung für Strukturforschung, Am Klopferspitz 18a, 82152, Martinsried, Germany.
