4hu8

Publication Abstract from PubMed

Bacterial Ig-like (Big) domains are commonly distributed in glycoside hydrolases (GH), but their structure and function remains undefined. Xylanase is a GH, and catalyzes the hydrolysis of the internal beta-xylosidic linkages of xylan. In this study, we report the molecular cloning, biochemical and biophysical characterization, and crystal structure of a termite gut bacterial xylanase, Xyl-ORF19, which was derived from gut bacteria of a wood-feeding termite (Globitermes brachycerastes). The protein architecture of Xyl-ORF19 reveals that it has two domains, a C-terminal GH10 catalytic domain and an N-terminal Big_2 non-catalytic domain. The catalytic domain folds in an (alpha/beta)8 barrel as most GH10 xylanases do, but it has two extra beta-strands. The non-catalytic domain is structurally similar to an immunoglobulin-like domain of intimins. The recombinant enzyme without the non-catalytic domain has fairly low catalytic activity, and is different from the full-length enzyme in kinetic parameters, pH and temperature profiles, which suggests the non-catalytic domain could affect the enzyme biochemical and biophysical properties as well as the role for enzyme localization. This study provides a molecular basis for future efforts in xylanase bioengineering. Biotechnol. Bioeng. 2013;9999: 1-11. (c) 2013 Wiley Periodicals, Inc.

Biochemical characterization and crystal structure of a GH10 xylanase from termite gut bacteria reveal a novel structural feature and significance of its bacterial Ig-like domain.,Han Q, Liu N, Robinson H, Cao L, Qian C, Wang Q, Xie L, Ding H, Wang Q, Huang Y, Li J, Zhou Z Biotechnol Bioeng. 2013 Jun 21. doi: 10.1002/bit.24982. PMID:23794438^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.