Enhanced the catalytic efficiency and thermostability of maltooligosyltrehalose synthase from Arthrobacter ramosus by directed evolution
Enhanced the catalytic efficiency and thermostability of maltooligosyltrehalose synthase from Arthrobacter ramosus by directed evolution
复制标题
通过定向进化增强支枝节杆菌麦芽低聚海藻糖合酶的催化效率和热稳定性
DOI：
10.1016/j.bej.2020.107724
复制
发表时间：
2020-10-15
影响因子：
3.9
通讯作者：
Wu, Jing
中科院分区：
文献类型：
--
作者：
Chen, Chun;Su, Lingqia;Wu, Jing
麦芽寡糖基海藻糖合酶（MTSase）是海藻糖制备过程中的关键酶。随着人们对海藻糖研究兴趣的增加，需要进一步改进MTSase的催化性能，以提高海藻糖的产率，但迄今为止，有关MTSase的修饰报道显示海藻糖的产率仅提高了1%。在这项研究中，MTSase从节杆菌ramosus的突变体S44 P是通过定向进化获得的，并显示出K-m从野生型的6.6 mM降低到3.5 mM，并且k（cat）/K-m增加了2.2倍。因此，S44 P的海藻糖产率为76.9%，比野生型酶的海藻糖产率高6.6%。这种提高的海藻糖产率对于工业应用具有潜在的重要意义。同时，与野生型相比，S44 P表现出增加的热稳定性。我们解决了野生型和突变型酶的结构，并评估其结构的差异，以阐明改变的性质，这为MTSase的未来修饰提供了见解。
Maltooligosyltrehalose synthase (MTSase) is a key enzyme in the preparation of trehalose. Increasing interest in trehalose requires further improvement in the catalytic performance of MTSase in order to increase trehalose yield, but so far, the reports about modification of MTSase revealed that the trahalose yield was increased only by 1%. In this study, the mutant S44 P of MTSase from Arthrobacter ramosus was obtained by directed evolution and showed a decrease in K-m to 3.5 mM from 6.6 mM of wild-type, and an increase in k(cat) /K-m by 2.2-fold. Thus, S44 P exhibited a trehalose yield of 76.9 %, which was 6.6 % higher than that obtained by wild-type enzyme. This improved trehalose yield is potentially of great importance for the industrial application. Meanwhile, S44 P exhibits increased thermostability compared to wild-type. We solved the structures of both wild-type and mutant enzymes and evaluated differences in their structures to elucidate the changed properties, which provides the insight for future modification of MTSase.