Construction of an Expression Vector pHis-EGFP with the Enhanced Green Fluorescent Protein (EGFP) Gene

The plasmid pHis-EGFP is a expression vector based on the plasmid pUC 18. It was constructed by assembling a T7 operator region, the 6×His tag coding sequence, the multiple cloning site, and T7 terminator from plasmid pET-32a(+) with the ColE 1 origin of the replicon and the fragment of the enhanced green fluorescent protein gene (EGFP) from pEGFP-N1. The constructed vector could be used to express the His-tagged, EGFP-labeled fusion proteins in Escherichia coli. Thus, the recombinant protein will be easy to detect and purified. With the constructed vector the geranylgeranyl diphosphate synthase of yeast has been successfully expressed in E. coli and purified. The result indicates that the constructed vector is effective and practicable. A simple, 2-step method of protein purification was developed by the combination of ion exchange and affinity chromatography.