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Improvement of the catalytic characteristics of a salt-tolerant GH10 xylanase from Streptomyce rochei L10904

Li, Qin, Sun, Baoguo, Li, Xiuting, Xiong, Ke, Xu, Youqiang, Yang, Ran, Hou, Jie, Teng, Chao
International journal of biological macromolecules 2018 v.107 pp. 1447-1455
carbohydrate binding, catalytic activity, corn cobs, mutants, salt tolerance, sodium chloride, thermal stability, xylan, xylanases, xylose
A GH10 xylanase Srxyn10 from Streptomyce rochei L10904, and its truncated derivative, Srxyn10M, were investigated. Both displayed great salt-tolerant ability, retaining more than 95% and 91% activity after incubation at 37°C for 1h in 3.0M and 5.0M NaCl, respectively. They exhibited a special hydrolytic property of forming xylobiose as the major product and produced fewer xylose compounds when combined with a reported xylanase while digesting corncob xylans. The mutant, Srxyn10M, was constructed from Srxyn10 by deleting the C-terminal carbohydrate-binding module. It possessed a 3.26-fold higher specific activity on beechwood xylan than Srxyn10. Moreover, Srxyn10M showed greater substrate affinity and catalytic efficiency than Srxyn10 when beechwood xylan, birchwood xylan, and oat-spelt xylan were used as substrates. The thermostability was also greatly improved. Therefore, the application potential was markedly enhanced by the improvement of these properties.