Polyhistidine-tag
（重定向自Histag）
![A simple column for Ni2+-affinity chromatography. The sample and subsequent buffers are manually poured into the column.](/Images/godic/202501/18/Simple_column_for_Ni2+-affinity_chromatography4650.jpg")
![Adding polyhistidine tags. A) The His-tag is added by inserting the DNA encoding a protein of interest in a vector that has the tag ready to fuse at the C-terminus. B) The His-tag is added using primers containing the tag, after a PCR reaction the tag gets fused to the N-terminus of the gene.](/Images/godic/202501/18/His-tag4650.png")
![](/Images/godic/202501/18/His-tag-primers4650.png")
A polyhistidine-tag is an amino acid motif in proteins that consists of at least six histidine (His) residues, often at the N- or C-terminus of the protein. It is also known as hexa histidine-tag, 6xHis-tag, His6 tag and by the trademarked name His-tag (registered by EMD Biosciences). The tag was invented by Roche, although the use of histidines and its vectors are distributed by Qiagen. Various purification kits for histidine-tagged proteins are available from Qiagen, Sigma, Thermo Scientific, GE Healthcare, Macherey-Nagel, Clontech, Bio-Rad, and others.