期刊
BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS
卷 1814, 期 12, 页码 1832-1840出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.bbapap.2011.07.020
关键词
Cellulose; Cellulase; Biofuel; Crystal structure; Synchrotron radiation
资金
- National Science Council of Taiwan [NSC98-3114-B-002-003, NSC98-2313-B-002-033-MY3]
- National Basic Research Program of China [2011CB710800]
- Tianjin Municipal Science and Technology Commission [10ZCKFSY06000]
The hyperthermophilic endoglucanase Cel5A from Thermotoga maritime can find applications in lignocellulosic biofuel production, because it catalyzes the hydrolysis of glucan- and mannan-based polysaccharides. Here, we report the crystal structures in apo-form and in complex with three ligands, cellotetraose, cellobiose and mannotriose, at 1,29 angstrom to 2.40 angstrom resolution. The open carbohydrate-binding cavity which can accommodate oligosaccharide substrates with extensively branched chains explained the dual specificity of the enzyme. Combining our structural information and the previous kinetic data, it is suggested that this enzyme prefers beta-glucosyl and beta-mannosyl moieties at the reducing end and uses two conserved catalytic residues, E253 (nucleophile) and E136 (general acid/base), to hydrolyze the glycosidic bonds. Moreover, our results also suggest that the wide spectrum of Tm_Cel5A substrates might be due to the lack of steric hindrance around the C2-hydroxyl group of the glucose or mannose unit from active-site residues. (C) 2011 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据