Purification of Poly-Histidine-Tagged Proteins

His-tagging is the most widespread and versatile strategy used to purify recombinant proteins for biochemical and structural studies. Recombinant DNA methods are first used to engineer the addition of a short tract of poly-histidine tag (His-tag) to the N terminus or C terminus of a target protein. The His-tag is then exploited to enable purification of the "tagged" protein by immobilised metal affinity chromatography (IMAC). Here, we describe efficient procedures for the isolation of highly purified His-tagged target proteins from an Escherichia coli host using IMAC.