7D89

Crystal structure of an inactivated double mutant (E182AE280A) of a novel thermostable GH10 xylanase XynA

7D89 の概要

• エントリーDOI: 10.2210/pdb7d89/pdb
• 分子名称: Beta-xylanase, CALCIUM ION (3 entities in total)
• 機能のキーワード: gh10 family, thermostable, inactivated, mutant, hydrolase
• 由来する生物種: Bacillus sp.
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 49887.07

構造登録者

Xie, W.,Yu, Q.,Wang, C. (登録日: 2020-10-07, 公開日: 2021-08-18, 最終更新日: 2023-11-29)

主引用文献

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

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: 34156819
DOI: 10.1021/acs.biochem.1c00134

実験手法

X-RAY DIFFRACTION (2.89384086853 Å)