4n9m | pdb_00004n9m

Joint neutron/x-ray structure of urate oxidase in complex with 8-hydroxyxanthine

spinqualitylabelsall models 4n9m, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4n9m is a 1 chain structure with sequence from Aspfl. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 8HX, CL, DOD, NA NonStd Res: ACE Related: 4n3m, 3l9g, 4n9s, 4n9v Gene: uaZ, uox (ASPFL) Activity: Factor independent urate hydroxylase, with EC number 1.7.3.3 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [URIC_ASPFL] Catalyzes the oxidation of uric acid to 5-hydroxyisourate, which is further processed to form (S)-allantoin. Publication Abstract from PubMed Urate oxidase transforms uric acid to 5-hydroxyisourate without the help of cofactors, but the catalytic mechanism has remained enigmatic, as the protonation state of the substrate could not be reliably deduced. We have determined the neutron structure of urate oxidase, providing unique information on the proton positions. A neutron crystal structure inhibited by a chloride anion at 2.3 A resolution shows that the substrate is in fact 8-hydroxyxanthine, the enol tautomer of urate. We have also determined the neutron structure of the complex with the inhibitor 8-azaxanthine at 1.9 A resolution, showing the protonation states of the K10-T57-H256 catalytic triad. Together with X-ray data and quantum chemical calculations, these structures allow us to identify the site of the initial substrate protonation and elucidate why the enzyme is inhibited by a chloride anion. The neutron structure of urate oxidase resolves a long-standing mechanistic conundrum and reveals unexpected changes in protonation.,Oksanen E, Blakeley MP, El-Hajji M, Ryde U, Budayova-Spano M PLoS One. 2014 Jan 23;9(1):e86651. doi: 10.1371/journal.pone.0086651. eCollection, 2014 Jan 23. PMID:24466188 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Urate Oxidase

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