Improvement of the catalytic performance of a Bispora antennata cellulase by replacing the N-terminal semi-barrel structure. (October 2016)

• Record Type: Journal Article
• Authors: Zheng, Fei; Huang, Huoqing; Wang, Xiaoyu; Tu, Tao; Liu, Qiong; Meng, Kun; Wang, Yuan; Su, Xiaoyun; Xie, Xiangming; Luo, Huiying
• Is Part Of: Bioresource technology. Volume 218(2016)
• Page Start: 279
• Page End: 285
• Publication Date: 2016-10
• Subjects: Cellulase -- Hybrid enzyme -- Glycosyl hydrolase (GH) family 5 -- Catalytic efficiency -- N-terminal (βα)-replacement; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2016.06.094
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: An acidic mesophilic cellulase of GH5 ( Ba Cel5) was identified in B. antennata . Effect of N-terminal barrel structures on its catalytic performance was studied. Replacing the N-terminal (βα)3 or (βα)4 barrel with that of Te Egl5A improved the specific activity up to 6.7-fold. Barrel structure replacement also improved the catalytic efficiency up to 4.7-fold. N-terminal replacement introduced more hydrogen bonds and enlarged catalytic cavity. Abstract: The aim of this work was to study the contribution of the N-terminal structure to cellulase catalytic performance. A wild-type cellulase ( Ba Cel5) of glycosyl hydrolase (GH) family 5 from Bispora antennata and two hybrid enzymes ( Ba Cel5 127 and Ba Cel5 167 ) with replacement of the N-terminal (βα)3 (127 residues) or (βα)4 (167 residues)-barrel with the corresponding sequences of Te Egl5A from Talaromyces emersonii were produced in Pichia pastoris and biochemically characterized. Ba Cel5 exhibited optimal activity at pH 5.0 and 50 °C but had low catalytic efficiency (25.4 ± 0.8 mL s −1 mg −1 ). In contrast, Ba Cel5 127 and Ba Cel5 167 showed similar enzymatic properties but improved catalytic performance. When using CMC-Na, barley β-glucan, lichenan, and cellooligosaccharides as substrates, Ba Cel5 127 and Ba Cel5 167 had increased specific activities and catalytic efficiencies by ∼1.8−6.7-fold and ∼1.0−4.7-fold, respectively. The catalytic efficiency of Ba Cel5 167 was even higher than that of parental proteins. The underlying mechanism was analyzed by molecular docking and molecular dynamic simulation.