Activating Compound | Comment | Organism | Structure |
---|---|---|---|
GTP | activating allosteric regulation by GTP. The regulatory triphosphate binds at a site in the center of the tetramer changing the quaternary arrangement. The effector contacts Pro94 at the beginning of a long beta-strand in the dimer interface, which extends into a flexible loop over the active site. In the GTP-bound state, two flexible loop residues, Tyr123 and Lys125, bind the diphosphate moiety of PRPP in the neighboring subunit and contribute to catalysis. The C-terminal Gly216 participates in a hydrogen-bond network in the dimer interface that stabilizes the inhibited, but not the activated, state | Saccharolobus solfataricus |
Crystallization (Comment) | Organism |
---|---|
two structures of the activated state enzyme in complex with GTP, X-ray diffraction structure determination and analysis at 2.8 A resolution, the first structure which contains PRPP in all active sites, and 2.9 A resolution, for the second structure with PRPP in two sites and the hydrolysis products ribose-5-phosphate and diphosphate in the other sites, respectively, and a third structure of the enzyme in complex with UMP and the allosteric inhibitor CTP | Saccharolobus solfataricus |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
CTP | inhibitory allosteric regulation by CTP. The regulatory triphosphate binds at a site in the center of the tetramer changing the quaternary arrangement. The effector contacts Pro94 at the beginning of a long beta-strand in the dimer interface, which extends into a flexible loop over the active site, two flexible loops. In the inhibited state, residues, Tyr123 and Lys125 contribute to the configuration of the active site for UMP rather than PRPP binding. The C-terminal Gly216 participates in a hydrogen-bond network in the dimer interface that stabilizes the inhibited, but not the activated, state | Saccharolobus solfataricus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | allosteric transition, structural and kinetic studies, overview | Saccharolobus solfataricus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
uracil + 5-phospho-alpha-D-ribose 1-diphosphate | Saccharolobus solfataricus | - |
UMP + diphosphate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Saccharolobus solfataricus | Q980Q4 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
uracil + 5-phospho-alpha-D-ribose 1-diphosphate | - |
Saccharolobus solfataricus | UMP + diphosphate | - |
? |
Subunits | Comment | Organism |
---|---|---|
tetramer | - |
Saccharolobus solfataricus |