title: Exploration of cellulose surface-binding properties of acidothermus cellulolyticus Cel5A by site-specific mutagenesis.
abstract: 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.
authors.affiliation: Biotechnology for Fuels and Chemicals Division, National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
authors.forename: Suzanne L
authors.initials: SL
authors.lastname: McCarter
authors.forename: William S
authors.initials: WS
authors.lastname: Adney
authors.forename: Todd B
authors.initials: TB
authors.lastname: Vinzant
authors.forename: Edward
authors.initials: E
authors.lastname: Jennings
authors.forename: Fannie Posey
authors.initials: FP
authors.lastname: Eddy
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Decker
authors.forename: John O
authors.initials: JO
authors.lastname: Baker
authors.forename: Joshua
authors.initials: J
authors.lastname: Sakon
authors.forename: Michael E
authors.initials: ME
authors.lastname: Himmel
mesh_terms: 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
chemical_list: D011994:Recombinant Proteins; D001224:Aspartic Acid; D002482:Cellulose; D001120:Arginine; C407024:endoglucanase Cel5A; D002480:Cellulase