3kvv

Trapping of an oxocarbenium ion intermediate in UP crystals

spinqualitylabelsall models 3kvv, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3kvv is a 6 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: R2B, SO4, URF Related: 3ku4, 3kuk, 3kvr, 3kvy Gene: UDP (Escherichia coli) Activity: Uridine phosphorylase, with EC number 2.4.2.3 Resources: FirstGlance, OCA, RCSB, PDBsum Function [UDP_ECOLI] Catalyzes the reversible phosphorylytic cleavage of uridine and deoxyuridine to uracil and ribose- or deoxyribose-1-phosphate. The produced molecules are then utilized as carbon and energy sources or in the rescue of pyrimidine bases for nucleotide synthesis. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Uridine phosphorylase is a key enzyme in the pyrimidine salvage pathway. This enzyme catalyzes the reversible phosphorolysis of uridine to uracil and ribose 1-phosphate (or 2'-deoxyuridine to 2'-deoxyribose 1-phosphate). Here we report the structure of hexameric Escherichia coli uridine phosphorylase treated with 5-fluorouridine and sulfate and dimeric bovine uridine phosphorylase treated with 5-fluoro-2'-deoxyuridine or uridine, plus sulfate. In each case the electron density shows three separate species corresponding to the pyrimidine base, sulfate, and a ribosyl species, which can be modeled as a glycal. In the structures of the glycal complexes, the fluorouracil O2 atom is appropriately positioned to act as the base required for glycal formation via deprotonation at C2'. Crystals of bovine uridine phosphorylase treated with 2'-deoxyuridine and sulfate show intact nucleoside. NMR time course studies demonstrate that uridine phosphorylase can catalyze the hydrolysis of the fluorinated nucleosides in the absence of phosphate or sulfate, without the release of intermediates or enzyme inactivation. These results add a previously unencountered mechanistic motif to the body of information on glycal formation by enzymes catalyzing the cleavage of glycosyl bonds. Glycal formation in crystals of uridine phosphorylase.,Paul D, O'Leary SE, Rajashankar K, Bu W, Toms A, Settembre EC, Sanders JM, Begley TP, Ealick SE Biochemistry. 2010 Apr 27;49(16):3499-509. PMID:20364833 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Uridine phosphorylase

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