Title : Structural analysis of glycoside hydrolase family 43, beta-xylosidase and its complex with xylose from mesophilic Pseudopedobacter saltans
Abstract:
In bioethanol production, enzymatic saccharification of lignocellulosic biomass is cost limiting step. Therefore, to reduce the production cost of bioethanol, the structural insights of new efficient Carbohydrate-Active enZYmes (CAZy) with high catalytic efficiency, productivity, high temperature and pH stability are required. Structural studies of CAZy enzymes are crucial for unraveling the mechanisms of catalysis, this in turn enhances their structural stability. Understanding, the detailed interactions and stability of these enzymes allows for better tailoring of their properties, leading to more effective biomass conversion and ultimately more sustainable biofuel production. β-1,4-xlyosidase is one of the XOS acting enzymes that specifically hydrolyzes beta 1-4 glycosidic bonds present between the two xylose units. According to the Carbohydrate Active Enzyme (CAZy) database, β-1,4-xlyosidase belongs to the glycoside hydrolase family 43 (GH43).
In this study, we reported two different crystal structures: the native β-1,4-xlyosidase and its complex with xylose in catalytic core from mesophilic Pseudopedobacter saltans. We have also performed biochemical characterization using various substrates. The native protein was crystallized using the hanging drop vapor diffusion method and data was collected at the European Synchrotron Radiation Facility, Grenoble, France at 2.5 Å resolution. The soaking experiments were conducted to obtain the complex structure with xylose, data collected at 2.8 Å resolution. The structure of native β-1,4-xlyosidase comprises two domains connected through a linker: the five-bladed β-propeller domain which catalyzes the substrate and a β sandwich domain which binds to the substrate. This study pinpoints the mechanism of action of GH43 β-1,4-xlyosidase in enzymatic degradation.
