Improving the thermostability of endo-β-1,4-glucanase by the fusion of a module subdivided from hyperthermophilic CBM9_1-2

Endo-1,4-glucanases have long been applied in many fields, such as in biomass waste conversion, papermaking, food, textile and animal feed production. To improve the thermostability of endo-beta-1,4-glucanase (CMCase-I), submodule C2 from hyperthermophilic CBM9_1-2 was inserted into the N- and C-terminal regions of the CMCase-I protein (producing C2-CMCase-I, CMCase-I-C2 and C2-CMCase-I-C2) by engineering. CMCase-I and the hybrid genes were successfully expressed in Escherichia coli BL21 (DE3). Enzymatic property analysis indicates that the C2 submodule only had a significant positive effect on the thermostability of CMCase-I glucanase. At the optimum temperature (50 degrees C), the half-life of the C2-CMCase-I chimera (313.91 min) was 1.53 times longer than that of wild-type glucanase CMCase-I (204.67 min). More importantly, structural analysis showed that the thermal stability of the C2-CMCase-I chimera was improved due to the formation of a new beta-sheet in the structure. In addition, this beta-sheet structure formed 3 pairs of effective hydrogen bonds, in contrast to the wild-type glucanase CMCase-I. The thermostability characteristics of C2-CMCase-I make this chimera a potential enzyme for industrial applications.

Automated summary

In this study, the thermostability of CMCase-I enzyme was improved by engineering and inserting the C2 submodule. The resulting C2-CMCase-I chimera showed significantly enhanced stability and the formation of a new beta-sheet structure. This chimera has potential for industrial applications.