Functional and structural studies of an atypical fungal endoglucanase

The importance of studying cellulases is not limited to the acquisition of scientific knowledge but also to the great biotechnological potential they represent. This is due to the fact that cellulose is the most abundant molecule present in nature and provides a wide range of sustainable products and processes. Many cellulase families have already been well characterized while others remain unknown. Among the latter family 45 of glycoside hydrolases is the least characterized family of fungal cellulases both structurally and functionally. In this book we report the crystallographic structure of the endoglucanase V enzyme from a microorganism called Phanerochaete chrysosporium (PcCel45A). We also report the structure of this enzyme with a ligand (cellobiose). In order to study its function we carried out studies on the enzyme's catalytic site using site-directed mutagenesis in the main residues of the active site. This enzyme showed a structure and mechanism of action that was totally different from the other enzymes in the family.