title: Adsorption characteristics of fungal family 1 cellulose-binding domain from Trichoderma reesei cellobiohydrolase I on crystalline cellulose: negative cooperative adsorption via a steric exclusion effect.
abstract: Cellobiohydrolases (CBHs) hydrolyzing crystalline cellulose share a two-domain structure of catalytic domain (CD) and cellulose-binding domain (CBD). To focus on the binding characteristics of CBD, we analyzed the adsorption of fusion protein of fungal family 1 CBD from  Trichoderma reesei  CBH I and red-fluorescent protein on crystalline and amorphous celluloses. Binding data were better fitted by Hill's model with negative cooperativity than by other adsorption models, suggesting the occurrence of a steric exclusion effect among the fusion molecules on the cellulose surfaces. The degree of negative cooperativity depended on the nature of the cellulose. The significance of this phenomenon for catalysis by intact CBHI is discussed.
authors.affiliation: Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Naohisa
authors.initials: N
authors.lastname: Sugimoto
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Igarashi
authors.forename: Masahisa
authors.initials: M
authors.lastname: Wada
authors.forename: Masahiro
authors.initials: M
authors.lastname: Samejima
mesh_terms: D000327:Adsorption; D002482:Cellulose / Q000737:chemistry* / Q000378:metabolism*; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D011993:Recombinant Fusion Proteins; D002482:Cellulose; D043366:Cellulose 1,4-beta-Cellobiosidase