ABSTRACT
Objective To prepare PTD4-Cu,Zn-SOD fusion protein.Methods The recombinant plasmid of pET 1 6b-Cu,Zn-SOD and pET16b-PTD4-Cu,Zn-SOD was transformed into Escherichia coli BL21 (DE3).Isopropyl β-D-1-thiogalactopyranoside was then added at a final concentration of 0.84 mmol/L,and the cells were incubated for 4 h to induce the expression of Cu,Zn-SOD and PTD4-Cu,Zn-SOD fusion protein.Lysozyme and ultrasound were used to lyse the bacteria,the supernatant was collected for 15％ SDS-PAGE to analyze the expression of the target protein.Ni-NTA His bind resin was used to purify Cu,Zn-SOD protein and PTD4-Cu,Zn-SOD fusion protein under natural conditions.Western blot was used to identify the target protein.Results The results of Western blot showed that the purity of the target protein was about 90％,and the Cu,Zn-SOD protein with a molecular weight about 19 kDa and the PTD4-Cu,Zn-SOD fusion protein with a molecular weight about 20 kDa were found.Conclusion PTD4-Cu,Zn-SOD fusion protein is prepared successfully.
ABSTRACT
Objective To construct the prokaryotic recombinant expression vector of PTD4-Cu,Zn-SOD.Methods By using the techniques of gene recombination,the primers of Cu,Zn-SOD and the oligonucleotide sequences of PTD4 were designed,PCR amplification was performed for Cu,Zn-SOD genes,the PCR products were identified,reclaimed and purified,and pET16b served as carrier.The prokaryotic recombinant expression vector of pET16b-Cu,Zn-SOD was constructed using double digestion with Xho Ⅰ and BamH Ⅰ,ligated reaction and plasmid transformation.Then PTD4 gene and pET16b-Cu,Zn-SOD carrier were double digested with Nde Ⅰ and Xho Ⅰ and ligated,and the plasmid was transformed,and the prokaryotic recombinant expression vector of pET16b-PTD4-Cu,Zn-SOD was constructed.The reconstructed vector was analyzed by restriction mapping and was verified by gene sequencing.Results The prokaryotic recombinant expression vector of pET16b-PTD4-Cu,Zn-SOD with a length of 6 207 bp was constructed successfully.The carrier fragment about 5.7 kp and PTD4-Cu,Zn-SOD gene fragment about 510 bp were obtained by double digestion with Nde Ⅰ and BamH Ⅰ,which was consistent with the expected results.The results of gene sequencing showed that the base sequences of pET16b-PTD4-Cu,Zn-SOD were correct when compared with the expected gene sequences.Conclusion The prokaryotic recombinant expression vector of pET16b-PTD4-Cu,Zn-SOD is constructed successfully.