1r87

Crystal structure of the extracellular xylanase from Geobacillus stearothermophilus T-6 (XT6, monoclinic form): The complex of the WT enzyme with xylopentaose at 1.67A resolution

spinqualitylabelsall models 1r87, resolution 1.67Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1r87 is a 1 chain structure with sequence from Atcc 12980. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, SO4, ZN, XYP Related: 1r85, 1r86 Gene: xynA (ATCC 12980) Activity: Endo-1,4-beta-xylanase, with EC number 3.2.1.8 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 Relating thermodynamic parameters to structural and biochemical data allows a better understanding of substrate binding and its contribution to catalysis. The analysis of the binding of carbohydrates to proteins or enzymes is a special challenge because of the multiple interactions and forces involved. Isothermal titration calorimetry (ITC) provides a direct measure of binding enthalpy (DeltaHa) and allows the determination of the binding constant (free energy), entropy, and stoichiometry. In this study, we used ITC to elucidate the binding thermodynamics of xylosaccharides for two xylanases of family 10 isolated from Geobacillus stearothermophilus T-6. The change in the heat capacity of binding (DeltaCp = DeltaH/DeltaT) for xylosaccharides differing in one sugar unit was determined by using ITC measurements at different temperatures. Because hydrophobic stacking interactions are associated with negative DeltaCp, the data allow us to predict the substrate binding preference in the binding subsites based on the crystal structure of the enzyme. The proposed positional binding preference was consistent with mutants lacking aromatic binding residues at different subsites and was also supported by tryptophan fluorescence analysis. Mapping glycoside hydrolase substrate subsites by isothermal titration calorimetry.,Zolotnitsky G, Cogan U, Adir N, Solomon V, Shoham G, Shoham Y Proc Natl Acad Sci U S A. 2004 Aug 3;101(31):11275-80. Epub 2004 Jul 26. PMID:15277671 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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