7cuc

Crystal Structure of Urate Oxidase from Bacillus sp. TB-90 in the absence from Chloride Anion at 1.44 A resolution

spinqualitylabelsall models 7cuc, resolution 1.44Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7cuc is a 2 chain structure with sequence from Bacillus sp. TB-90. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.44Å Ligands: AZA, MXE, NA, OXY, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PUCL_BACSB Catalyzes two steps in the degradation of uric acid, i.e. the oxidation of uric acid to 5-hydroxyisourate (HIU) and the stereoselective decarboxylation of 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) to (S)-allantoin (By similarity). Publication Abstract from PubMed Urate oxidases catalyze the cofactor-independent oxidation of uric acid, and an extensive water network in the active site has been suggested to play an essential role in the catalysis. For our present analysis of the structure and function of the water network, the crystal qualities of Bacillus sp. TB-90 urate oxidase (BTUO) were improved by controlled dehydration using the humid air and glue-coating method. After the dehydration, the P21212 crystals were transformed into the I222 space group, leading to an extension of the maximum resolution to 1.42 A. The dehydration of the crystals revealed a significant change in the five-water-molecules' binding mode in the vicinity of the catalytic diad, indicating that these molecules are quasi-stable. The pH profile analysis of log(kcat) gave two pKa values: pKa1 at 6.07 +/- 0.07 and pKa2 at 7.98 +/- 0.13. The site-directed mutagenesis of K13, T73, and N276 involved in the formation of the active-site water network revealed that the activities of these mutant variants were significantly reduced. These structural and kinetic data suggest that the five quasi-stable water molecules play an essential role in the catalysis of the cofactor-independent urate oxidation by reducing the energy penalty for the substrate-binding or an on-off switching for the proton-relay rectification. Identification of quasi-stable water molecules near the Thr73-Lys13 catalytic diad of Bacillus sp. TB-90 urate oxidase by X-ray crystallography with controlled humidity.,Hibi T, Itoh T J Biochem. 2020 Oct 1. pii: 5917020. doi: 10.1093/jb/mvaa114. PMID:33002140 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Urate oxidase 3D structures

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