2o73

Structure of OHCU decarboxylase in complex with allantoin

spinqualitylabelsall models 2o73, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2o73 is a 6 chain structure with sequence from Danio rerio. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.8Å Ligands: 2AL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function URAD_DANRE Catalyzes the stereoselective decarboxylation of 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) to (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 complete degradation of uric acid to (S)-allantoin, as recently elucidated, involves three enzymatic reactions. Inactivation by pseudogenization of the genes of the pathway occurred during hominoid evolution, resulting in a high concentration of urate in the blood and susceptibility to gout. Here, we describe the 1.8A resolution crystal structure of the homodimeric 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline decarboxylase, which catalyzes the last step in the urate degradation pathway, for both ligand-free enzyme and enzyme in complex with the substrate analogs (R)-allantoin and guanine. Each monomer comprises ten alpha-helices, grouped into two domains and assembled in a novel fold. The structure and the mutational analysis of the active site have allowed us to identify some residues that are essential for catalysis, among which His-67 and Glu-87 appear to play a particularly significant role. Glu-87 may facilitate the exit of the carboxylate group because of electrostatic repulsion that destabilizes the ground state of the substrate, whereas His-67 is likely to be involved in a protonation step leading to the stereoselective formation of the (S)-allantoin enantiomer as reaction product. The structural and functional characterization of 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline decarboxylase can provide useful information in view of the potential use of this enzyme in the enzymatic therapy of gout. The structure of 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline decarboxylase provides insights into the mechanism of uric acid degradation.,Cendron L, Berni R, Folli C, Ramazzina I, Percudani R, Zanotti G J Biol Chem. 2007 Jun 22;282(25):18182-9. Epub 2007 Apr 11. PMID:17428786 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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