2zka

Urate oxidase complexed with 8-azaxanthine under 1.0 MPa oxygen pressure

spinqualitylabelsall models 2zka, resolution 1.61Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2zka is a 1 chain structure with sequence from Aspergillus flavus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.61Å Ligands: ACE, AZA, NA, OXY 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. 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 The localization of dioxygen sites in oxygen-binding proteins is a nontrivial experimental task and is often suggested through indirect methods such as using xenon or halide anions as oxygen probes. In this study, a straightforward method based on x-ray crystallography under high pressure of pure oxygen has been developed. An application is given on urate oxidase (UOX), a cofactorless enzyme that catalyzes the oxidation of uric acid to 5-hydroxyisourate in the presence of dioxygen. UOX crystals in complex with a competitive inhibitor of its natural substrate are submitted to an increasing pressure of 1.0, 2.5, or 4.0 MPa of gaseous oxygen. The results clearly show that dioxygen binds within the active site at a location where a water molecule is usually observed but does not bind in the already characterized specific hydrophobic pocket of xenon. Moreover, crystallizing UOX in the presence of a large excess of chloride (NaCl) shows that one chloride ion goes at the same location as the oxygen. The dioxygen hydrophilic environment (an asparagine, a histidine, and a threonine residues), its absence within the xenon binding site, and its location identical to a water molecule or a chloride ion suggest that the dioxygen site is mainly polar. The implication of the dioxygen location on the mechanism is discussed with respect to the experimentally suggested transient intermediates during the reaction cascade. Oxygen pressurized X-ray crystallography: probing the dioxygen binding site in cofactorless urate oxidase and implications for its catalytic mechanism.,Colloc'h N, Gabison L, Monard G, Altarsha M, Chiadmi M, Marassio G, Sopkova-de Oliveira Santos J, El Hajji M, Castro B, Abraini JH, Prange T Biophys J. 2008 Sep;95(5):2415-22. Epub 2008 Mar 28. PMID:18375516 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Urate oxidase 3D structures

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