7-21: Crystal structure and performance testing of Caldicellulosiruptor bescii CelA

Unlike fungal cellulase systems which typically produce multiple single enzymes for biomass degradation such as family 7 and family 5 glycoside hydrolases, some bacterial systems utilize an alternative strategy that utilizes tethered multi-enzyme complexes to effectively degrade biomass. The enzyme CelA from the thermopile Caldicellulosiruptor bescii is one such example. The modular structure of CelA is defined as: Cel48-Cbm3-Cbm3-Cbm3-Cel9 and the enzyme is extremely thermostable and highly active at elevated temperatures.

We will present 2.4 Å resolution structures of the GH48 and GH9 modules of CelA as well as biochemical performance data of this enzyme on a variety of process relevant feedstocks. We will also present circular dichroism (CD) secondary structure data and thermostability measurements. Understanding the structures, the performance, and the thermostability of this interesting enzyme is critical to understanding and improving the effectiveness of this enzyme on biomass degradation.