7-12: Insights into the molecular-level mechanism of a processive, glycosylated cellulase from molecular simulation

The Hypocrea jecorina Family 6 cellobiohydrolase (Cel6A) is a key enzyme in industrial cocktails used to deconstruct cellulose into soluble sugars for conversion to biofuels. Here, we use a variety of molecular simulation approaches to gain insight into the molecular-level mechanisms of Cel6A in cellulose deconstruction. With thermodynamic integration, MD simulations, and normal mode analysis, we define the roles of the aromatic residues lining the active site tunnel, which has broad implications for many other glycoside hydrolase enzymes in terms of carbohydrate metabolism. With umbrella sampling and MD simulation, we examine the behavior of the multi-modular domain enzyme on a cellulose microfibril, evaluating the effect of microfibril morphology and linker glycosylation on the enzyme dynamics at the crystal surface of cellulose. Our results highlight new roles for the sub-domains of this key cellulase enzyme.