OVERPRODUCTION OF BETA-GLUCOSIDASE IN ACTIVE FORM BY AN ESCHERICHIA-COLI SYSTEM COEXPRESSING THE CHAPERONIN GROEL ES/

beta-Glucosidase from Cellvibrio gilvus was successfully overproduced in soluble form in Escherichia coli with the coexpression of GroEL/ES. Without the GroEL/ES protein: the beta-glucosidase overexpressed in E . coli constituted a huge amount (80%) of the total cellular protein, but was localized in the insoluble fraction, and little activity was d etected in the soluble fraction. Coexpression of the E. coli GroEL/ES had a drastic impact on the proper folding of the beta-glucosidase; 20 % of the overexpressed enzyme was recovered in the soluble fraction in active form. In addition, the synergistic effect of GroEL/ES and the low induction temperature led to 70% solubilization of the total expre ssed target protein and more than a 20-fold increase in activity. Simi lar effects of GroEL/ES were also observed on the overexpressed beta-g lucosidase From Agrobacterium tumefaciens. (C) 1998 Federation of Euro pean Microbiological Societies. Published by Elsevier Science B.V.