Improving enzyme characteristics by gene shuffling; application to β-glucosidase

The genes of family 3 β-glucosidase enzymes consist of five distinct regions; the N-terminal residues, an N-terminal catalytic domain, a nonhomologous region, a C-terminal domain of unknown function and the C-terminal residues. The β-glucosidase genes derived from Cellvibrio gilvus (CG) and Agrobacterium tumefaciens (AT) have been subjected to gene deletion, truncation and shuffling. The folding information was found to be distributed unevenly across the different regions based on the gene manipulation results. Chimeric enzymes with improved enzyme characteristics were obtained only by gene shuffling at the C-terminal domain.