3m0k

Structure of oxaloacetate acetylhydrolase in complex with the product oxalate

spinqualitylabelsall models 3m0k, resolution 1.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3m0k is a 1 chain structure with sequence from Cryphonectria parasitica. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.65Å Ligands: CA, MN, OXL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 Oxalacetate acetylhydrolase (OAH), a member of the phosphoenolpyruvate mutase/isocitrate lyase superfamily, catalyzes the hydrolysis of oxalacetate to oxalic acid and acetate. This study shows that knock-out of the oah gene in Cryphonectria parasitica, the chestnut blight fungus, reduces the ability of the fungus to form cankers on chestnut trees, suggesting that OAH plays a key role in virulence. OAH was produced in Escherichia coli and purified, and its catalytic rates were determined. Oxalacetate is the main OAH substrate, but the enzyme also acts as a lyase of (2R,3S)-dimethyl malate with approximately 1000-fold lower efficacy. The crystal structure of OAH was determined alone, in complex with a mechanism-based inhibitor, 3,3-difluorooxalacetate (DFOA), and in complex with the reaction product, oxalate, to a resolution limit of 1.30, 1.55, and 1.65 A, respectively. OAH assembles into a dimer of dimers with each subunit exhibiting an (alpha/beta)(8) barrel fold and each pair swapping the 8th alpha-helix. An active site "gating loop" exhibits conformational disorder in the ligand-free structure. To obtain the structures of the OAH.ligand complexes, the ligand-free OAH crystals were soaked briefly with DFOA or oxalacetate. DFOA binding leads to ordering of the gating loop in a conformation that sequesters the ligand from the solvent. DFOA binds in a gem-diol form analogous to the oxalacetate intermediate/transition state. Oxalate binds in a planar conformation, but the gating loop is largely disordered. Comparison between the OAH structure and that of the closely related enzyme, 2,3-dimethylmalate lyase, suggests potential determinants of substrate preference. Structure of oxalacetate acetylhydrolase, a virulence factor of the chestnut blight fungus.,Chen C, Sun Q, Narayanan B, Nuss DL, Herzberg O J Biol Chem. 2010 Aug 20;285(34):26685-96. Epub 2010 Jun 17. PMID:20558740 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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