Docking and Molecular Dynamics Study of the Carbohydrate Binding Module from Trichoderma reesei Cel7A on the Surfaces of the Cellulose IIII Crystal

Abstract

We report the systematic survey of the binding free energies at the interface between a carbohydrate binding module (CBM) of Cel7A and the cellulose III_I crystal model using grid docking searches and molecular dynamics simulations. The two hydrophobic crystal surfaces were involved in the distinct energy minima of the binding free energy. The complex models, each with the CBM at the minimum energy position, stably formed in the solution state. The binding free energies of the cellulose III_I complex models, based on both static and dynamics states, were comparable to those of the native cellulose complex models. However, the cellulose III_I crystal had a larger binding surface, which is compatible with the observed high enzymatic activity of Cel7A for the cellulose III_I substrate.