8JST

GH11 family xylanase rMxylcd from the compost-soil metagenome

8JST の概要

• エントリーDOI: 10.2210/pdb8jst/pdb
• 分子名称: Endo-beta-1,4-xylanase rMxylcd, GLYCEROL (3 entities in total)
• 機能のキーワード: glycoside hydrolase, thermostable xylanase, disulfide bond, hydrolase
• 由来する生物種: compost metagenome
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 21414.19

構造登録者

Wu, S.N.,Zhang, N.Y.,Wan, Q. (登録日: 2023-06-20, 公開日: 2024-06-26, 最終更新日: 2025-06-04)

主引用文献

Wu, S.,Zhang, N.,Wan, Q.
Disulfide bonds enhance thermal stability and thumb region drives activity of the glycoside hydrolase 11 xylanase rMxyl cd .
J.Struct.Biol., 217:108209-108209, 2025

PubMed Abstract: Thermostable enzymes have significant advantages in industries, yet uncovering novel candidates with superior properties remains a scientific pursuit. This study identified rMxyl, a glycoside hydrolase 11 family thermophilic xylanase from compost-soil metagenome, which exhibited a high specific activity of 5954 U·mg at pH 5.5 and 80°C. rMxyl was crystallized and diffracted to 1.5 Å resolution. Compared to the mesophilic xylanase Xyn II, rMxyl exhibits a more compact architecture. Notably, B-factor analysis reveals a uniquely flexible thumb region, hinting at its critical role in the enzyme's catalytic mechanism. rMxyl contains two disulfide bonds in the thumb and the N-terminal regions. Breaking these disulfide bonds by mutagenesis has dramatically decreased activities and thermostability. Conversely, introducing an extra disulfide bond at the N-terminal region of its α-helix extended its half-life for more than five folds at 80°C. Our studies firmly establish that the disulfide bonds are essential for its high thermal stability and the flexibility of the thumb region is crucial for its activity. Comparing the rMxyl crystal structure with the AlphaFold2-predicted model shows overall similarity, but the crystal structure offers higher local accuracy, especially in key functional regions. These findings not only deepen our understanding of the structure-function relationship of thermophilic xylanases but also inform a rational design of industrial enzymes.

PubMed: 40368259
DOI: 10.1016/j.jsb.2025.108209

実験手法

X-RAY DIFFRACTION (1.5 Å)