Expression and purification of HIS-IFNβ fusion protein in E.coli BL21(DE3)

Objective To express and purify the fusion protein HIS-IFNβ of human interferon β(IFNβ) and His-tag in E.coli BL21(DE3).Methods IFNβ gene was obtained from the total DNA of human Bel-7402 cell by PCR.IFNβ gene was then inserted into prokaryotic expression vector pET-16b and transformed into E.coli BL21(DE3).The expressed product was purified by affinity chromatography using Ni-NTA column and its antigenicity was analyzed by Western blotting analysis.The specific biological activity was detected by standard survival activity test on Wish cells challenged with VSV virus.Results SDS-PAGE result indicated HIS-IFNβ was expressed at the right molecular weight after induced by IPTG.Western blotting test showed the protein had reaction with either IFNβ monoclonal antibody or His-tag antibody.The purity of HIS-IFNβ purified by affinity chromatography reached 92% and the specific activity was about 4.2 × 107 U/mg.Conclusions The fusion protein of human interferon β with His-tag was successfully expressed and purified in E.coli BL21(DE3).The bioactivity of the fusion protein has been identified by cell anti-virus test.