短小芽孢杆菌木聚糖酶的同源建模及分子动力学模拟

Homology Modeling and Molecular Dynamic Simulation of Xylanase from Bacillus pumilus

克隆并测序来源于短小芽孢杆菌的木聚糖酶基因,测定其编码产物的理化性质并鉴定其表达产物为常温酶蛋白.利用同源建模构建出具有较高精度的三级结构模型,并进行优化和评估.利用分子动力学模拟木聚糖酶基因对热不稳定的分子机制,了解影响该酶热稳定性的因素,寻找对热不稳定性的区域.通过与嗜热木聚糖酶比较发现,两者在3个区域的分子动力学行为存在较明显的差异.

The gene of xylanase from Bacillus pumilus was cloned and sequenced.This xylanase was identified as a mesophilic enzyme.The tertiary structure of the xylanase originated from homology modeling was evaluated and optimized.Based on the optimal structure,molecular dynamic simulation of the mesophilic xylanase and a thermphilic one was performed using NAMD.The results showed that there were three regions which showed differences between the mesophilic and thermophilic xylanase.The molecular dynamic analysis suggested regions in the protein structure which were more unstable and thus potential targets for mutation to improve its thermostability.