Approximately 5 L of the plasmid preparations containing the inserted amplicons were used to transform competent E. coli DH 5cells by heat shock, and the transformed cells were plated on Luria-Bertani medium (LB) plates containing ampicillin(100 g/mL) plus IPTG (0.1 mM) and X-Gal (20 g/mL). The recombinant colonies were identified based on the white color of the colonies and then transferred to liquid LB medium containing ampicillin (100 g/mL) and incubated at 37◦C for 12 h at 250 rpm.
The presence of recombinant colonies containing the target fragment was confirmed by PCR using the primers RD6F and RD6R.
These PCR products were purified for nucleotide sequencing using the QIAquick@ PCR Purification Kit, following the protocol provided by the manufacturer