2b4f

Structure Of A Cold-Adapted Family 8 Xylanase in complex with substrate

spinqualitylabelsall models 2b4f, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2b4f is a 1 chain structure with sequence from Pseudoalteromonas haloplanktis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.95Å Ligands: XYP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8RJN8_PSEHA 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 structures of inactive mutants D144A and E78Q of the glycoside hydrolase family 8 (GH-8) endo-beta-1,4-d-xylanase (pXyl) from the Antarctic bacterium Pseudoalteromonas haloplanktis TAH3a in complex with its substrate xylopentaose (at 1.95 A resolution) and product xylotriose (at 1.9 A resolution) have been determined by X-ray crystallography. A detailed comparative analysis of these with the apo-enzyme and with other GH-8 structures indicates an induced fit mechanism upon ligand binding whereby a number of conformational changes and, in particular, a repositioning of the proton donor into a more catalytically competent position occurs. This has also allowed for the description of protein-ligand interactions in this enzyme and for the demarcation of subsites -3 to +3. An in-depth analysis of each of these subsites gives an insight into the structure-function relationship of this enzyme and the basis of xylose/glucose discrimination in family 8 glycoside hydrolases. Furthermore, the structure of the -1/+1 subsite spanning complex reveals that the substrate is distorted from its ground state conformation. Indeed, structural analysis and in silico docking studies indicate that substrate hydrolysis in GH-8 members is preceded by a conformational change, away from the substrate ground-state chair conformation, to a pretransition state local minimum (2)S(O) conformation. Oligosaccharide binding in family 8 glycosidases: crystal structures of active-site mutants of the beta-1,4-xylanase pXyl from Pseudoaltermonas haloplanktis TAH3a in complex with substrate and product.,De Vos D, Collins T, Nerinckx W, Savvides SN, Claeyssens M, Gerday C, Feller G, Van Beeumen J Biochemistry. 2006 Apr 18;45(15):4797-807. PMID:16605248 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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