Chen Anke, Wang Dan, Ji Rui, Li Jixi, Gu Shaohua, Tang Rong, Ji Chaoneng
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China.
Front Microbiol. 2021 Oct 1;12:723678. doi: 10.3389/fmicb.2021.723678. eCollection 2021.
Beta-glucosidase is an enzyme that catalyzes the hydrolysis of the glycosidic bonds of cellobiose, resulting in the production of glucose, which is an important step for the effective utilization of cellulose. In the present study, a thermostable β-glucosidase was isolated and purified from the sp. ex4484_79 and subjected to enzymatic and structural characterization. The purified β-glucosidase (TsBGL) exhibited maximum activity at 90°C and pH 5.0 and displayed maximum specific activity of 139.2μmol/min/mg against -nitrophenyl β-D-glucopyranoside (NPGlc) and 24.3μmol/min/mg against cellobiose. Furthermore, TsBGL exhibited a relatively high thermostability, retaining 84 and 47% of its activity after incubation at 85°C for 1.5h and 90°C for 1.5h, respectively. The crystal structure of TsBGL was resolved at a resolution of 2.14Å, which revealed a classical (α/β)-barrel catalytic domain. A structural comparison of TsBGL with other homologous proteins revealed that its catalytic sites included Glu210 and Glu414. We provide the molecular structure of TsBGL and the possibility of improving its characteristics for potential applications in industries.
β-葡萄糖苷酶是一种催化纤维二糖糖苷键水解的酶，水解产物为葡萄糖，这是纤维素有效利用的重要一步。在本研究中，从sp. ex4484_79中分离并纯化了一种耐热β-葡萄糖苷酶，并对其进行了酶学和结构表征。纯化后的β-葡萄糖苷酶（TsBGL）在90°C和pH 5.0时表现出最大活性，对β-D-硝基苯葡萄糖苷（NPGlc）的最大比活性为139.2μmol/min/mg，对纤维二糖的最大比活性为24.3μmol/min/mg。此外，TsBGL表现出较高的热稳定性，在85°C孵育1.5小时和90°C孵育1.5小时后，分别保留了84%和47%的活性。TsBGL的晶体结构分辨率为2.14Å，揭示了一个经典的（α/β）-桶状催化结构域。TsBGL与其他同源蛋白的结构比较表明，其催化位点包括Glu210和Glu414。我们提供了TsBGL的分子结构以及改善其特性以用于工业潜在应用的可能性。
