The cellulose-binding domain of the major cellobiohydrolase of Trichoderma reesei exhibits true reversibility and a high exchange rate on crystalline cellulose.

AUTOR(ES)

Linder, M

RESUMO

Cellulose-binding domains (CBDs) bind specifically to cellulose, and form distinct domains of most cellulose degrading enzymes. The CBD-mediated binding of the enzyme has a fundamental role in the hydrolysis of the solid cellulose substrate. In this work we have investigated the reversibility and kinetics of the binding of the CBD from Trichoderma reesei cellobiohydrolase I on microcrystalline cellulose. The CBD was produced in Escherichia coli, purified, and radioactively labeled by reductive alkylation with 3H. Sensitive detection of the labeled CBD allowed more detailed analysis of its behavior than has been possible before, and important novel features were resolved. Binding of the CBD was found to be temperature sensitive, with an increased affinity at lower temperatures. The interaction of the CBD with cellulose was shown to be fully reversible and the CBD could be eluted from cellulose by simple dilution. The rate of exchange measured for the CBD-cellulose interaction compares well with the hydrolysis rate of cellobiohydrolase I, which is consistent with its proposed mode of action as a processive exoglucanase.

Documentos Relacionados

• Characterization of the cellulose-binding domain of the Clostridium cellulovorans cellulose-binding protein A.
• Mutation analysis of the cellulose-binding domain of the Clostridium cellulovorans cellulose-binding protein A.
• Cellulose-binding domains promote hydrolysis of different sites on crystalline cellulose
• Crystal structure of a bacterial family-III cellulose-binding domain: a general mechanism for attachment to cellulose.
• Use of Recombinant Cellulose-Binding Domains of Trichoderma reesei Cellulase as a Selective Immunocytochemical Marker for Cellulose in Protozoa