State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States.
Int J Biol Macromol. 2019 Oct 15;139:1002-1008. doi: 10.1016/j.ijbiomac.2019.08.075. Epub 2019 Aug 8.
Cellobiose 2-epimerase (CE) is a promising industrial enzyme that can be utilized in the dairy industry. More thermostable CEs from different microorganisms are still needed for a higher lactulose productivity. This study demonstrated the feasibility to use molecular dynamics (MD) simulation as the preliminary computational filter for thermostable enzymes screening. Sequence information of eleven uncharacterized CEs were chosen to be analyzed by MD simulations. The CE from Dictyoglomus thermophilum (Dith-CE) was determined experimentally to be one of the most thermostable CEs with the highest epimerization (160 ± 6.5 U mg) and isomerization activities (3.52 ± 0.23 U mg) among all the reported CEs. This enzyme shows the highest isomerization activity at 85 °C and pH 7.0. The kinetic parameters (k and K) of isomerization activity of this CE are 3.98 ± 0.3 s and 235.2 ± 11.2 mM, respectively. These results suggest that the CE from Dith-CE is a promising lactulose-producing enzyme.
纤维二糖 2-差向异构酶（CE）是一种有前途的工业酶，可用于乳制品行业。为了提高半乳糖产量，仍需要来自不同微生物的更耐热的 CE。本研究证明了使用分子动力学（MD）模拟作为耐热酶筛选的初步计算筛选器的可行性。选择了十一种未表征的 CE 的序列信息进行 MD 模拟分析。实验确定嗜热 Dictyoglomus thermophilum（Dith-CE）中的 CE 是所有报道的 CE 中最耐热的 CE 之一，具有最高的差向异构化（160±6.5 U mg）和异构化活性（3.52±0.23 U mg）。该酶在 85°C 和 pH 7.0 下表现出最高的异构化活性。该 CE 的异构化活性的动力学参数（k 和 K）分别为 3.98±0.3 s 和 235.2±11.2 mM。这些结果表明，Dith-CE 中的 CE 是一种很有前途的半乳糖生产酶。
