11-04: Computational and experimental studies of fungal cellulases

Fungal cellulases are the cornerstone of modern enzyme cocktails for biomass deconstruction to soluble sugars, and understanding the mechanisms they employ at the molecular level is of significant importance for improvements to stability and activity. Here, we apply a large suite of computational tools (and experiments where possible) to understand how fungal cellulases bind to, depolymerize, and hydrolyze cellulose. Specifically, we use theory and experiment in concert to demonstrate that glycosylation has a significant influence on a wide range of properties of the Family 1 carbohydrate-binding modules and linkers typical of fungal cellulases. We examine the role that pH plays in cellulase activity and stability, especially related to catalysis and processivity. We apply advanced sampling methods to examine how Glycoside Hydrolase Family 7 cellulases employ a two-step reaction mechanism, both in solution and on the surface of a cellulose crystal. Lastly, we will cover recent work to examine the ligand binding free energy of a cellodextrin chain to GH Family 7 cellobiohydrolases, which is hypothesized to be related to the degree of processivity and the ability of a cellulase to depolymerize cellulose.