Biochemical and structural properties of a low-temperature-active glycoside hydrolase family 43 beta-xylosidase: Activity and instability at high neutral salt concentrations.
Zhang, R., Li, N., Liu, Y., Han, X., Tu, T., Shen, J., Xu, S., Wu, Q., Zhou, J., Huang, Z.(2019) Food Chem 301: 125266-125266
- PubMed: 31387037 
- DOI: https://doi.org/10.1016/j.foodchem.2019.125266
- Primary Citation of Related Structures:  
6IFE - PubMed Abstract: 
β-Xylosidase, of the glycoside hydrolase family 43 from Bacillus sp. HJ14, was expressed in Escherichia coli. Recombinant β-xylosidase (rHJ14GH43) exhibited maximum activity at 25 °C, approximately 15, 45, and 88% of maximum activity at 0, 10, and 20 °C, respectively, and poor stability at temperatures over 20 °C. rHJ14GH43 showed moderate or high activity, but poor stability, in NaCl, KCl, NaNO 3 , KNO 3 , Na 2 SO 4 , and (NH 4 ) 2 SO 4 at concentrations from 3.0 to 30.0% (w/v). The crystal structure of rHJ14GH43 was resolved and showed higher structural flexibility due to fewer salt bridges and hydrogen bonds compared to mesophilic and thermophilic β-xylosidases. High structural flexibility is presumed to be a key factor for catalytic adaptations to low temperatures and high salt concentrations. Approximately one-third of the surface of rHJ14GH43 is positively charged, which may be the primary factor responsible for poor stability in high neutral salt environments.
Organizational Affiliation: 
Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, PR China; College of Life Sciences, Yunnan Normal University, Kunming 650500, PR China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, PR China.