Study of active site adjacent residues on Serratia marcescens B4A chitinase catalytic activity

Chitinases are one of the important industrial enzymes which have significant role in different industries such as digestion of chitin and chitoligosaccharides, bioremediation and control of plants pathogenic fungal as well as insects. This enzyme catalyzes the β 1→6 glycoside bond and then hydrolyses chitin polymers. chitinases consists of a (ß/α)8-barrel catalytic domain contain of conserved sequence called DXDXE motif on β4 strand which D, E and residue around of this conserved sequence have essential role in cleavage and hydrolysis of the glycosidic bond. Study of active site adjacent amino acids can help us to understand their function in catalytic properties. In this project are mutated Ser390 and Gly191 for investigating role of this two residue existing in the adjacent of conserved sequence at catalytically process of Serratia marcescens B4A chitinase and after of cloning in expression vector and analysis of expression with SDS-PAGE are investigated effect of two mutations on the enzyme activity.