Download MendeleyCrystal structure of the ATPPase subunit and its substrate-dependent association with the GATase Subunit: a novel regulatory mechanism for a two-subunit-type GMP synthetase from Pyrococcus horikoshii OT3.
Maruoka, S., Horita, S., Lee, W.C., Nagata, K., Tanokura, M.(2010) J Mol Biol 395: 417-429
- PubMed: 19900465
- DOI: https://doi.org/10.1016/j.jmb.2009.10.053
- Primary Citation of Related Structures:
3A4I - PubMed Abstract:
Guanosine 5'-monophosphate synthetase(s) (GMPS) catalyzes the final step of the de novo synthetic pathway of purine nucleotides. GMPS consists of two functional units that are present as domains or subunits: glutamine amidotransferase (GATase) and ATP pyrophosphatase (ATPPase). GATase hydrolyzes glutamine to yield glutamate and ammonia, while ATPPase utilizes ammonia to convert adenyl xanthosine 5'-monophosphate (adenyl-XMP) into guanosine 5'-monophosphate. Here we report the crystal structure of PH-ATPPase (the ATPPase subunit of the two-subunit-type GMPS from the hyperthermophilic archaeon Pyrococcus horikoshii OT3). PH-ATPPase consists of two domains (N-domain and C-domain) and exists as a homodimer in the crystal and in solution. The N-domain contains an ATP-binding platform called P-loop, whereas the C-domain contains the xanthosine 5'-monophosphate (XMP)-binding site and also contributes to homodimerization. We have also demonstrated that PH-GATase (the glutamine amidotransferase subunit of the two-subunit-type GMPS from the hyperthermophilic archaeon P. horikoshii OT3) alone is inactive, and that all substrates of PH-ATPPase except for ammonia (Mg(2+), ATP and XMP) are required to stabilize the active complex of PH-ATPPase and PH-GATase subunits.
Organizational Affiliation:
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
