Li Qin, Sun Baoguo, Jia Huiyong, Hou Jie, Yang Ran, Xiong Ke, Xu Youqiang, Li Xiuting
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing 100048, China; School of Food and Chemical Engineering, Beijing Technology and Business University, No.33, Fucheng Road, Beijing 100048, China.
School of Food and Chemical Engineering, Beijing Technology and Business University, No.33, Fucheng Road, Beijing 100048, China; Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology and Business University (BTBU), Beijing 100048, China.
Int J Biol Macromol. 2017 Aug;101:366-372. doi: 10.1016/j.ijbiomac.2017.03.135. Epub 2017 Mar 27.
Protein engineering was performed by N-terminal region replacement and site-directed mutagenesis in the cord of a xylanase (Srxyn) from Streptomyce rochei L10904 to improve its catalytic characteristics. Three mutants SrxynF, SrxynM and SrxynFM displayed 2.1-fold, 3.2-fold and 5.3-fold higher specific activities than that of Srxyn, respectively. Moreover, all of the mutants showed greater substrate affinity and k/K than the native Srxyn. In addition, the enzymes showed improved hydrolysis characteristics, of which the most noteworthy is the enhanced ability of producing xylobiose (X2) and xylotriose (X3) from polymeric substrates. The engineered xylanases have greater potential for applications in oligosaccharide preparation industry.
通过对罗氏链霉菌L10904木聚糖酶（Srxyn）的N端区域替换和定点诱变进行蛋白质工程改造，以改善其催化特性。三个突变体SrxynF、SrxynM和SrxynFM的比活性分别比Srxyn高2.1倍、3.2倍和5.3倍。此外，所有突变体都表现出比天然Srxyn更高的底物亲和力和k/K。另外，这些酶的水解特性得到改善，其中最值得注意的是从聚合底物产生木二糖（X2）和木三糖（X3）的能力增强。工程化木聚糖酶在低聚糖制备工业中具有更大的应用潜力。
