Construction and Expression of the Plasmid Vector of the Human α_1-Microglobulin in Escharichia Coli

ObjectiveTo construct a recombinant plasmid expressing theα_1-microglobulin(α_1-MG) from human liver and purify the target protein. MethodscDNA of human α_1-mg was obtained by RT-PCR from the tissue of human liver. The gene was constructed into the pET-15b expression vector and expression in Escharichia coli BL21(DE3) after transformation and induction by IPTG. The complete protein of the host bacteria was extracted for SDS-PAGE. Afterwards the recombinant protein with an N-terminal His tag sequence was purified by affinity chromatography on a Ni~(2+)-Sepharose column. ResultsThe expressed humanα_1-MG in Escherichia coli was formed in inclusion body. After denaturation and renaturation, the inclusion protein became a soluble form with nature conformation. ConclusionThe humanα_1-MG was successfully expressed and purified, which can be used to get polyclone or monoclone antibody.