Model cellulose films exposed to H. insolens glucoside hydrolase family 45 endo-cellulase--the effect of the carbohydrate-binding module.
The effects of enzyme structure and activity on the degradation of model cellulose substrates were investigated by ellipsometry for the cellulase Humicola insolens GH45. The inactive variant D10N was found to adsorb at the cellulose surface but also to be incorporated into the cellulose films to an extent that depended on pH. For the native protein, the initial adsorption monitored for the inactive variant D10N was followed by enzyme-mediated degradation of the cellulose films. Again, a dependence on pH was found, such that higher pH resulted in slower enzymatic degradation. Removing the carbohydrate-binding module eliminated this pH dependence but also resulted in a decreased adsorption to the cellulose surface, and in a decreased net catalytic effect.
Eriksson
Jonny
J
Institute for Surface Chemistry, Box 5607, SE-114 86 Stockholm, Sweden. jonny.olaspers@bredband.net
Malmsten
Martin
M
Tiberg
Fredrik
F
Callisen
Thomas Hønger
TH
Damhus
Ture
T
Johansen
Katja S
KS
D001203:Ascomycota / Q000201:enzymology*; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose; D005656:Fungal Proteins / Q000378:metabolism; D005959:Glucosidases / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D011487:Protein Conformation
D005656:Fungal Proteins; D002482:Cellulose; D005959:Glucosidases; D002480:Cellulase