Effect of carbohydrate binding modules alterations on catalytic activity of glycoside hydrolase family 6 exoglucanase from Chaetomium thermophilum to cellulose

• Published in: International journal of biological macromolecules Vol. 191; pp. 222 - 229
• Main Authors: Hu, Yanmei, Li, Huanan, Ran, Qiuping, Liu, Jiashu, Zhou, Shanna, Qiao, Qiming, Song, Huiting, Peng, Fang, Jiang, Zhengbing
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30.11.2021
• Subjects: Binding ability; Binding Sites; Carbohydrate binding module; Catalytic activity; Cellulose - chemistry; Cellulose - metabolism; Cellulose 1,4-beta-Cellobiosidase - chemistry; Cellulose 1,4-beta-Cellobiosidase - genetics; Cellulose 1,4-beta-Cellobiosidase - metabolism; Chaetomium - enzymology; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungal Proteins - metabolism; Hydrolysis; Protein Binding; Binding ability; Carbohydrate binding module; Catalytic activity
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2021.09.002

Exoglucanase (CBH) is the rate limiting enzyme in the process of cellulose degradation. The carbohydrate binding module (CBM) can improve the accessibility of cellulase to substrate, thereby promoting the enzymatic hydrolysis of cellulase. In this study, the influence of CBM on the properties of GH6 exoglucanase from Chaetomium thermophilum (CtCBH) is systematically explored from three perspectives: the fusion of exogenous CBM, the exogenous CBM replacement of its own CBM, and the deletion of its own CBM. The parental and reconstructed CtCBH presented the same optimum pH (6.0) and temperature (60 °C) for maximum activity. Fusion of exogenous CBM increased the binding capacity of CtCBH to Avicel by 8% and 9%, respectively, but it had no significant effect on its catalytic activity. The exogenous CBM replacement of its own CBM resulted in a 12% reduction in the binding ability of CtCBH to Avicel, and a 26% reduction in the catalytic activity of Avicel. The deletion of its own CBM significantly reduced the binding ability of CtCBH to Avicel by approximately 53%, but its catalytic activity was not obviously reduced. These observations suggest that binding ability of CBM is not necessary for the catalysis of CtCBH. •CBM is not necessary for the catalysis of CtCBH.•The deletion of CBM significantly reduced the binding ability of CtCBH.•The deletion of CBM did not significantly reduce its catalytic activity.•The fusion of exogenous CBM can improve the binding ability of CtCBH.•The replacement of CBM affected the catalytic activity and binding ability of CtCBH.