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Title: Catalytic Mechanism of Cellulose Degradation by a Cellobiohydrolase, CelS

Abstract

The hydrolysis of cellulose is the bottleneck in cellulosic ethanol production. The cellobiohydrolase CelS from Clostridium thermocellum catalyzes the hydrolysis of cello-oligosaccharides via inversion of the anomeric carbon. Here, to examine key features of the CelS-catalyzed reaction, QM/MM (SCCDFTB/MM) simulations are performed. The calculated free energy profile for the reaction possesses a 19 kcal/mol barrier. The results confirm the role of active site residue Glu87 as the general acid catalyst in the cleavage reaction and show that Asp255 may act as the general base. A feasible position in the reactant state of the water molecule responsible for nucleophilic attack is identified. Sugar ring distortion as the reaction progresses is quantified. The results provide a computational approach that may complement the experimental design of more efficient enzymes for biofuel production.

Authors:
 [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1017392
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 5; Journal Issue: 10; Journal ID: ISSN 1932--6203
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; BIOFUELS; CARBON; CATALYSTS; CELLULOSE; CELLULOSIC ETHANOL; CLEAVAGE; CLOSTRIDIUM THERMOCELLUM; DESIGN; ENZYMES; FREE ENERGY; HYDROLYSIS; PRODUCTION; RESIDUES; SACCHAROSE; WATER

Citation Formats

Saharay, Moumita, Guo, Hong, and Smith, Jeremy C. Catalytic Mechanism of Cellulose Degradation by a Cellobiohydrolase, CelS. United States: N. p., 2010. Web. doi:10.1371/journal.pone.0012947.
Saharay, Moumita, Guo, Hong, & Smith, Jeremy C. Catalytic Mechanism of Cellulose Degradation by a Cellobiohydrolase, CelS. United States. https://doi.org/10.1371/journal.pone.0012947
Saharay, Moumita, Guo, Hong, and Smith, Jeremy C. 2010. "Catalytic Mechanism of Cellulose Degradation by a Cellobiohydrolase, CelS". United States. https://doi.org/10.1371/journal.pone.0012947.
@article{osti_1017392,
title = {Catalytic Mechanism of Cellulose Degradation by a Cellobiohydrolase, CelS},
author = {Saharay, Moumita and Guo, Hong and Smith, Jeremy C},
abstractNote = {The hydrolysis of cellulose is the bottleneck in cellulosic ethanol production. The cellobiohydrolase CelS from Clostridium thermocellum catalyzes the hydrolysis of cello-oligosaccharides via inversion of the anomeric carbon. Here, to examine key features of the CelS-catalyzed reaction, QM/MM (SCCDFTB/MM) simulations are performed. The calculated free energy profile for the reaction possesses a 19 kcal/mol barrier. The results confirm the role of active site residue Glu87 as the general acid catalyst in the cleavage reaction and show that Asp255 may act as the general base. A feasible position in the reactant state of the water molecule responsible for nucleophilic attack is identified. Sugar ring distortion as the reaction progresses is quantified. The results provide a computational approach that may complement the experimental design of more efficient enzymes for biofuel production.},
doi = {10.1371/journal.pone.0012947},
url = {https://www.osti.gov/biblio/1017392}, journal = {PLoS ONE},
issn = {1932--6203},
number = 10,
volume = 5,
place = {United States},
year = {Sun Aug 01 00:00:00 EDT 2010},
month = {Sun Aug 01 00:00:00 EDT 2010}
}