3A4I: Crystal Structure Of Gmp Synthetase Ph1347 From Pyrococcus Horikoshii Ot3

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.
PDB ID: 3A4IDownload
MMDB ID: 75434
PDB Deposition Date: 2009/7/7
Updated in MMDB: 2009/07
Experimental Method:
x-ray diffraction
Resolution: 1.79  Å
Source Organism:
Similar Structures:
Biological Unit for 3A4I: dimeric; determined by author and by software (PISA)
Molecular Components in 3A4I
Label Count Molecule
Proteins (2 molecules)
GMP Synthase [glutamine-hydrolyzing] Subunit B(Gene symbol: PH_RS06390)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB