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Cellulose chain binding free energy drives the processive move of cellulases on the cellulose surface
Author(s) -
Wang Yefei,
Zhang Shujun,
Song Xiangfei,
Yao Lishan
Publication year - 2016
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.25970
Subject(s) - processivity , cellulase , cellulose , trichoderma reesei , cellobiose , chemistry , biochemistry , hydrolysis , biophysics , enzyme , biology , polymerase
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.