A novel pH-stable, endoglucanase (JqCel5A) isolated from a salt-lake microorganism, Jonesia quinghaiensis

作者：Lin, Ling^*; Liu, Xiaozhou; Zhou, Yating; Guan, Linyan; He, Jiajia; Huang, Weiqian

来源：Electronic Journal of Biotechnology, 2016, 24: 56-62.

DOI：10.1016/j.ejbt.2016.09.004

• Protein modeling
• Site-directed mutagenesis
• Cellulases
• Recombinant endoglucanase gene
• Catalytic domain of glycoside hydrolase
• Carbohydrate-binding module
• High pH stability
• Tolerance to deleterious chemicals
• Tolerance to heavy metals
• Tolerance to detergents

Background: Endoglucanase, one of three type cellulases, can randomly cleave internal beta-1,4-linkages in cellulose polymers. Thus, it could be applied in agricultural and industrial processes.
Results: A novel endoglucanase gene (JqCel5A) was cloned from Jonesia quinghaiensis and functionally expressed in Escherichia coli Rosetta (DE3). It contained 1722 bp and encoded a 573-residue polypeptide consisting of a catalytic domain of glycoside hydrolase family 5 (GH5) and a type 2 carbohydrate-binding module (CBM2), together with a predicted molecular mass of 61.79 kD. The purified JqCel5A displayed maximum activity at 55 degrees C and pH 7.0, with 21.7 U/mg, 26.19 U/mg and 4.81 U/mg towards the substrate carboxymethyl cellulose, barley glucan and filter paper, respectively. Interestingly, JqCel5A exhibited high pH stability over a broad pH range of pH (3-11), and had good tolerance to a wide variety of deleterious chemicals including heavy metals and detergent. The catalytic mechanism of JqCel5A was also investigated by site mutagenesis and homology-modeling in this study.
Conclusions: It was believed that these properties might make JqCel5A to be potentially used in the suitable industrial catalytic condition, which has a broad pH fluctuation and/or chemical disturbance.

• 出版日期2016-11
• 单位安徽师范大学