Structural basis for the mechanism of inhibition of uridine phosphorylase from Salmonella typhimurium
The three-dimensional structures of three complexes of Salmonella typhimurium uridine phosphorylase with the inhibitor 2,2'-anhydrouridine, the substrate PO{sub 4}, and with both the inhibitor 2,2'-anhydrouridine and the substrate PO{sub 4} (a binary complex) were studied in detail by X-ray diffraction. The structures of the complexes were refined at 2.38, 1.5, and 1.75 A resolution, respectively. Changes in the three-dimensional structure of the subunits in different crystal structures are considered depending on the presence or absence of the inhibitor molecule and (or) the phosphate ion in the active site of the enzyme. The presence of the phosphate ion in the phosphate-binding site was found to substantially change the orientations of the side chains of the amino-acid residues Arg30, Arg91, and Arg48 coordinated to this ion. A comparison showed that the highly flexible loop L9 is unstable. The atomic coordinates of the refined structures of the complexes and the corresponding structure factors were deposited in the Protein Data Bank (their PDB ID codes are 3DD0 and 3C74). The experimental data on the spatial reorganization of the active site caused by changes in its functional state from the unligated to the completely inhibited state suggest the structural basis for the mechanism of inhibition of Salmonella typhimurium uridine phosphorylase.
- OSTI ID:
- 22051244
- Journal Information:
- Crystallography Reports, Vol. 55, Issue 1; Other Information: Copyright (c) 2010 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7745
- Country of Publication:
- United States
- Language:
- English
Similar Records
Isolation, crystallization and preliminary crystallographic analysis of Salmonella typhimurium uridine phosphorylase crystallized with 2,2′-anhydrouridine
In silico analysis of the three-dimensional structures of the homodimer of uridine phosphorylase from Yersinia Pseudotuberculosis in the ligand-free state and in a complex with 5-fluorouracil