7D88
Crystal structure of a novel thermostable GH10 xylanase XynA
Summary for 7D88
| Entry DOI | 10.2210/pdb7d88/pdb |
| Descriptor | Beta-xylanase, CALCIUM ION (3 entities in total) |
| Functional Keywords | gh10 family, thermostable, bifunctional., hydrolase |
| Biological source | Bacillus sp. |
| Total number of polymer chains | 1 |
| Total formula weight | 50003.14 |
| Authors | |
| Primary citation | Xie, W.,Yu, Q.,Zhang, R.,Liu, Y.,Cao, R.,Wang, S.,Zhan, R.,Liu, Z.,Wang, K.,Wang, C. Insights into the Catalytic Mechanism of a Novel XynA and Structure-Based Engineering for Improving Bifunctional Activities. Biochemistry, 60:2071-2083, 2021 Cited by PubMed Abstract: 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 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 Å. 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_ΔN36 toward beechwood xylan, wheat arabinoxylan, filter paper, and barley β-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_ΔN36 provide clues for the further use of XynA in industrial applications. PubMed: 34156819DOI: 10.1021/acs.biochem.1c00134 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.34482019351 Å) |
Structure validation
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