4yek

X-ray structure of the thymidine phosphorylase from Salmonella typhimurium in complex with thymidine

spinqualitylabelsall models 4yek, resolution 2.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4yek is a 2 chain structure with sequence from Salmonella enterica subsp. enterica serovar Typhimurium. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EDO, GOL, PGE, SO4, THM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TYPH_SALTY The enzymes which catalyze the reversible phosphorolysis of pyrimidine nucleosides are involved in the degradation of these compounds and in their utilization as carbon and energy sources, or in the rescue of pyrimidine bases for nucleotide synthesis. Publication Abstract from PubMed Highly specific thymidine phosphorylases catalyze the phosphorolytic cleavage of thymidine, with the help of a phosphate ion, resulting in thymine and 2-deoxy-alpha-D-ribose 1-phosphate. Thymidine phosphorylases do not catalyze the phosphorolysis of uridine, in contrast to nonspecific pyrimidine nucleoside phosphorylases and uridine phosphorylases. Understanding the mechanism of substrate specificity on the basis of the nucleoside is essential to support rational drug-discovery investigations of new antitumour and anti-infective drugs which are metabolized by thymidine phosphorylases. For this reason, X-ray structures of the thymidine phosphorylase from Salmonella typhimurium were solved and refined: the unliganded structure at 2.05 A resolution (PDB entry 4xr5), the structure of the complex with thymidine at 2.55 A resolution (PDB entry 4yek) and that of the complex with uridine at 2.43 A resolution (PDB entry 4yyy). The various structural features of the enzyme which might be responsible for the specificity for thymidine and not for uridine were identified. The presence of the 2'-hydroxyl group in uridine results in a different position of the uridine furanose moiety compared with that of thymidine. This feature may be the key element of the substrate specificity. The specificity might also be associated with the opening/closure mechanism of the two-domain subunit structure of the enzyme. Structural investigation of the thymidine phosphorylase from Salmonella typhimurium in the unliganded state and its complexes with thymidine and uridine.,Balaev VV, Lashkov AA, Gabdulkhakov AG, Dontsova MV, Seregina TA, Mironov AS, Betzel C, Mikhailov AM Acta Crystallogr F Struct Biol Commun. 2016 Mar 1;72(Pt 3):224-33. doi:, 10.1107/S2053230X1600162X. Epub 2016 Feb 19. PMID:26919527 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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