Function Of Linker Region Between Catalytic Module And Carbohydrate-binding Module In The Endoglucanases Of Bacillus Subtilis'strsain 115

Thermolstable cellulose Cel 115 of Bacillus subtilis strain 115 is composed of a catalytic module(CM),carbohydrate-binding carbohydrate-binding(CBM),which are jointed by a flexible linker region(LR).In order to evaluate the function of LR,we made the 6 mutants which were LR-null and LRs with 1 to 5 repeats.We studied their kinetics,adsorption,activity,thermodynamic and pH stability,and relative flexibilities.The data indicated that the mutant which contained three LRs had the highest activity in the normal situation.And the mutants with fewer LRs were much more stable,but had lower ability in binding to microcrystalline cellulose,as versus those with longer LRs had a higher catalytic efficiency at low and moderate temperatures.