Restriction endonucleases, PrimeSTARTM HS DNA Polymerase
and T4 DNA ligase were purchased from Takara, China. Genomic
DNA Purification Kit was obtained from Dongsheng, China. Gel
extraction kit and Plasmid Miniprep kit were obtained from
Axygen, China. Primers were synthesized by Invitrogen, China.
Ni–NTA resins were purchased from GE Healthcare Bio-Science AB, Sweden