Molecular modeling of cellulose hydrolysis: The hydrated Cel7a linker peptide

Plant biomass is the most abundant source of fermentable carbohydrates in the world, which when converted to fuels such as ethanol, holds the potential for significant environmental, economic, and strategic gains. Cellobiohydrolase I (Cel7A), from Trichoderma reesei, is one of the most active cellulases known. Cel7A is a multi-domain exoglucanase enzyme, consisting of a large catalytic domain containing an active site tunnel and a small cellulose binding module joined to one another by a 27 residue linker peptide. This enzyme, which is found in fungal cellulase systems, is believed to hydrolyze cellulose in a processive manner, beginning from a reduced end of a cellodextrine chain, liberating cellobiose residues. Computer simulations of the O-linked glycosylated linker peptide in an aqueous environment are carried out to gain insight into the role the linker may play in cellulose hydrolysis. Preliminary results for the interaction of the peptide with a cellulose surface are also presented to study possible interactions of the linker with the surface. This is an abstract of a paper presented at the AIChE Annual Meeting and Fall Showcase (Cincinnati, OH 10/30/2005-11/4/2005).