Exploration of cellulose surface-binding properties of acidothermus cellulolyticus Cel5A by site-specific mutagenesis.
Understanding the interactions between cellulases and cellulosic substrates is critical to the development of an efficient artificial cellulase system for conversion of biomass to sugars. We directed specific mutations to the interactive surface of the Acidothermus cellulolyticus EI endoglucanase catalytic domain. The cellulose-binding domain is not translated in these mutants. Amino acid mutations were designed either to change the surface charge of the protein or to modify the potential for hydrogen bonding with cellulose. The relationship between cellulase-to-cellulose (Avicel PH101) binding and hydrolysis activity was determined for various groupings of mutations. While a significant increase in hydrolysis activity was not observed, certain clusters of residues did significantly alter substrate binding and some interesting correlations emerged. In the future, these observations may be used to aid the design of endoglucanases with improved performance on pretreated biomass.
McCarter
Suzanne L
SL
Biotechnology for Fuels and Chemicals Division, National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
Adney
William S
WS
Vinzant
Todd B
TB
Jennings
Edward
E
Eddy
Fannie Posey
FP
Decker
Stephen R
SR
Baker
John O
JO
Sakon
Joshua
J
Himmel
Michael E
ME
D000192:Actinomycetales / Q000201:enzymology*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001120:Arginine; D001224:Aspartic Acid; D001665:Binding Sites; D020134:Catalytic Domain; D002480:Cellulase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002482:Cellulose / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013499:Surface Properties
D011994:Recombinant Proteins; D001224:Aspartic Acid; D002482:Cellulose; D001120:Arginine; C407024:endoglucanase Cel5A; D002480:Cellulase