Abstract:
Using overlap extension PCR, two amino acid residues Y127 and R254 within the conserved protein domain of β-cyclodextrin glucosyl transferase were subjected to site-directed mutagenesis, respectively.The mutant genes were subcloned into prokaryotic expression vector pUC-18, by PCR and sequence analysis, these recombinant expression plasmids were transformed into Escherichia coli BL21 (DE3) for effective expression, respectively.It can be proved that expression vectors of Y127F and R254F were successfully constructed.