3p9f

Urate oxidase-azaxanthine-azide ternary complex

spinqualitylabelsall models 3p9f, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3p9f 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: AZA, AZI, NA NonStd Res: ACE Related: 1r4s, 3bjp, 3obp, 3l8w, 3p9o 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 BACKGROUND: Urate oxidase (EC 1.7.3.3 or UOX) catalyzes the conversion of uric acid and gaseous molecular oxygen to 5-hydroxyisourate and hydrogen peroxide, in the absence of cofactor or particular metal cation. The functional enzyme is a homo-tetramer with four active sites located at dimeric interfaces. RESULTS: The catalytic mechanism was investigated through a ternary complex formed between the enzyme, uric acid, and cyanide that stabilizes an intermediate state of the reaction. When uric acid is replaced by a competitive inhibitor, no complex with cyanide is formed. CONCLUSION: The X-ray structure of this compulsory ternary complex led to a number of mechanistic evidences that support a sequential mechanism in which the two reagents, dioxygen and a water molecule, process through a common site located 3.3 A above the mean plane of the ligand. This site is built by the side chains of Asn 254, and Thr 57, two conserved residues belonging to two different subunits of the homo-tetramer. The absence of a ternary complex between the enzyme, a competitive inhibitor, and cyanide suggests that cyanide inhibits the hydroxylation step of the reaction, after the initial formation of a hydroperoxyde type intermediate. Structural analysis of urate oxidase in complex with its natural substrate inhibited by cyanide: mechanistic implications.,Gabison L, Prange T, Colloc'h N, El Hajji M, Castro B, Chiadmi M BMC Struct Biol. 2008 Jul 20;8:32. PMID:18638417 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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