Polyhistidine tag (His-tag) (His-tag)

The polyhistidine tag, commonly referred to as a His-tag, is an amino acid motif consisting of at least six histidine residues typically fused to the N- or C-terminus of a recombinant protein (Hochuli et al., 1988). It is one of the most widely used affinity tags in molecular biology and biotechnology for the purification of proteins from various expression systems (Bornhorst and Falke, 2000). The tag operates on the principle of immobilized metal affinity chromatography (IMAC), where the imidazole rings of the histidine residues form coordinate covalent bonds with transition metal ions like nickel (Ni2+) or cobalt (Co2+) immobilized on a resin (Block et al., 2009). This interaction allows for the selective capture and subsequent elution of the tagged protein using imidazole or a low pH buffer (Hochuli et al., 1988). While primarily a laboratory tool for protein engineering and structural biology, the His-tag is not a natural therapeutic target in human physiology (Bornhorst and Falke, 2000). However, it is frequently employed in the production of therapeutic proteins and vaccines, where its removal is often required to prevent potential immunogenicity or interference with the protein's biological activity (Block et al., 2009).

Other names

6xHis-tagHexahistidine tagHis6 tagPoly-His tag

Not applicable as this is an artificial peptide tag used for protein purification and detection, not a therapeutic target.