S3: Exploring the nano confinement space for cell wall degrading molecular machines

Nature has engineered a number of approaches for the assembly and deconstruction of plant cell walls. Plants and microorganisms synthesize these molecular machines for a number of goals, and these molecular machines must operate within a complex heterogeneous catalyst framework to polymerize simple carbohydrates and depolymerize the polymers to make cell walls a dynamic structure for plant cell growth, to overcome plant defenses, and to provide simple carbohydrates for microbial growth and activities.  At the most fundamental level cellulases must bind and react on the surface of exposed cellulose micro-fibrils.  This heterogeneous reaction takes place on arrays of densely packed cellulose polymers with a width of 3 to 5 nm and length on the order of a few hundred nanometers. Cellulases also have characteristic dimensions on the scale of 5 to 20 nm. However, these nano-scale interactions are often masked by the enzyme transport challenges such as pore diffusion limitation and steric hindrance that are determined by the pore size distribution of the substrate.  Thus, any effort to resolve cellulase binding, mobility and synergistic interactions must also consider the influence of the micro-scale pore structure on enzyme transport to the reactive sites.  This presentation will presented some of the methods and research outcomes that have evolved out of a multidisciplinary program at Cornell focused on understanding these nano- and micro-scale interactions.