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Determination of the molecular states of the processive endocellulase Thermobifida fusca Cel9A during crystalline cellulose depolymerization
Author(s) -
Kostylev Maxim,
MoranMirabal Jose M.,
Walker Larry P.,
Wilson David B.
Publication year - 2012
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.23299
Subject(s) - cellulase , cellulose , depolymerization , chemistry , glycoside hydrolase , substrate (aquarium) , cell wall , cellulosome , biochemistry , clostridium thermocellum , enzyme , hemicellulose , organic chemistry , biology , ecology
Detailed understanding of cell wall degrading enzymes is important for their modeling and industrial applications, including in the production of biofuels. Here we used Cel9A, a processive endocellulase from Thermobifida fusca, to demonstrate that cellulases that contain a catalytic domain (CD) attached to a cellulose binding module (CBM) by a flexible linker exist in three distinct molecular states. By measuring the ability of a soluble competitor to reduce Cel9A activity on an insoluble substrate, we show that the most common state of Cel9A is bound via its CBM, but with its CD unoccupied by the insoluble substrate. These findings are relevant for kinetic modeling and microscopy studies of modular glycoside hydrolases. Biotechnol. Bioeng. 2012;109: 295–299. © 2011 Wiley Periodicals, Inc.