The crystallographic structure of GH5-106: A new biomass degrading enzyme from thermal spring bacteria

This study presents the crystallographic structure of GH5-106, a novel mannanase of family GH5. This enzyme was found in a scanning of metagenomes from thermal springs, while searching for natural thermostable and thermoactive cellulases that may be used in bioethanol production.
Bioethanol is a promoted alternative fuel, which production improves constantly with further research. Bioethanol production utilizes carbohydrates-based biomass that exist in practically unlimited masses on our planet, making it a desired substitute for fossil-fuels.
The first step of bioethanol production is degrading polysaccharides into simple sugars, preferably by dedicated enzymes that can do it quickly and efficiently.
GH5 is an important enzyme family employed for this critical step, consisting of over ten thousand enzymes from all taxa that catalyze the hydrolysis of the glycosidic bonds in oligo- and polysaccharides. Therefore, GH5 enzymes form an attractive pool of biomass degrading catalysts, especially those thermostable ones isolated from thermal springs.
GH5-106 was recently crystallized and its 3D structure solved to 1.6 Å resolution, allowing now its comprehensive structure-function study. Such study includes the determination of the exact mode of action, and further improvement of the catalytic properties of this enzyme by structure-based rational mutagenesis, making it better suited for various industrial applications.