For easy expression in E. coli, optimized gene of CALB and TLL
were synthesized. They were inserted into the corresponding
restriction enzyme sites of plasmid pRSFDuet to give recombinant
expression plasmid pRSFDuet-Calb and pRSFDuet-Tll, respectively.
CALB gene was also inserted into the corresponding restriction enzyme
sites of plasmid pRSFDuet-Tll to give recombinant co-expression
plasmid pRSFDuet-Calb-Tll. After transformation into E. coli BL
21 (DE3) and selection with kanamycin, E. coli (Calb/Tll) coexpressing
CALB and TLL with one plasmid (pRSFDuet-Calb-Tll)
and E. coli (Calb-Tll) co-expressing the two enzymes with two plasmids
(PETDuet-Calb and pRSFDuet-Tll) were obtained. In addition,
E. coli (Calb) expressing CALB and E. coli (Tll) expressing TLL were
also engineered for comparison.