title: Cellulose chain binding free energy drives the processive move of cellulases on the cellulose surface.
abstract: Processivity is essential for cellulases in their catalysis of cellulose hydrolysis. But what drives the processive move is not well understood. In this work, we use Trichoderma reesei Cel7B as a model system and show that its processivity is directly correlated to the binding free energy difference of a cellulose chain occupying the binding sites -7 to +2 and that occupying sites -7 to -1. Several mutants that have stronger interactions with glycosyl units in sites +1 and +2 than the wild type enzyme show higher processivity. The results suggest that after the release of the product cellobiose located in sites +1 and +2, the enzyme pulls the cellulose chain to fill the vacant sites, which propels its processive move on the cellulose surface. Biotechnol. Bioeng. 2016;113: 1873-1880. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Shandong Provincial Key Laboratory of Synthetic Biology, Chinese Academy of Sciences, Qingdao, China.|Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China.
authors.forename: Yefei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Shandong Provincial Key Laboratory of Synthetic Biology, Chinese Academy of Sciences, Qingdao, China.|Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China.
authors.forename: Shujun
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Shandong Provincial Key Laboratory of Synthetic Biology, Chinese Academy of Sciences, Qingdao, China.|Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China.
authors.forename: Xiangfei
authors.initials: X
authors.lastname: Song
authors.affiliation: Shandong Provincial Key Laboratory of Synthetic Biology, Chinese Academy of Sciences, Qingdao, China. yaols@qibebt.ac.cn.|Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China. yaols@qibebt.ac.cn.
authors.forename: Lishan
authors.initials: L
authors.lastname: Yao
mesh_terms: D044602:Cellulases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics; D014242:Trichoderma / Q000201:enzymology / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D011994:Recombinant Proteins; D002482:Cellulose; D044602:Cellulases
keywords: Cel7B; Trichoderma reesei; free energy calculations; processivity