7d88

Crystal structure of a novel thermostable GH10 xylanase XynA

spinqualitylabelsall models 7d88, resolution 2.34Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7d88 is a 1 chain structure with sequence from Bacillus sp. (in: Bacteria). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.3448203Å Ligands: CA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A4P8ESF9_BACSP Publication Abstract from PubMed Xylan and cellulose are the two major constituents of numerous types of lignocellulose. The bifunctional enzyme that exhibits xylanase/cellulase activity has attracted a great deal of attention in biofuel production. Previously, a thermostable GH10 family enzyme (XynA) from Bacillus sp. KW1 was found to degrade both xylan and cellulose. To improve bifunctional activity on the basis of structure, we first determined the crystal structure of XynA at 2.3 A. Via molecular docking and activity assays, we revealed that Gln250 and His252 were indispensable to bifunctionality, because they could interact with two conserved catalytic residues, Glu182 and Glu280, while bringing the substrate close to the activity pocket. Then we used a structure-based engineering strategy to improve xylanase/cellulase activity. Although no mutants with increased bifunctional activity were obtained after much screening, we found the answer in the N-terminal 36-amino acid truncation of XynA. The activities of XynA_DeltaN36 toward beechwood xylan, wheat arabinoxylan, filter paper, and barley beta-glucan were significantly increased by 0.47-, 0.53-, 2.46-, and 1.04-fold, respectively. Furthermore, upon application, this truncation released more reducing sugars than the wild type in the degradation of pretreated corn stover and sugar cane bagasse. These results showed the detailed molecular mechanism of the GH10 family bifunctional endoxylanase/cellulase. The basis of these catalytic performances and the screened XynA_DeltaN36 provide clues for the further use of XynA in industrial applications. Insights into the Catalytic Mechanism of a Novel XynA and Structure-Based Engineering for Improving Bifunctional Activities.,Xie W, Yu Q, Zhang R, Liu Y, Cao R, Wang S, Zhan R, Liu Z, Wang K, Wang C Biochemistry. 2021 Jul 6;60(26):2071-2083. doi: 10.1021/acs.biochem.1c00134. Epub, 2021 Jun 22. PMID:34156819 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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