The oligohistidine domain is a Ni2+-binding peptide sequence comprising a string of four to six histidine residues. When the DNA sequence corresponding to the oligohistidine domain is fused in frame with a gene of interest, the resulting fusion protein can be easily purified using a nickel-chelating resin. The Penta-His monoclonal IgG1 antibody provides a sensitive method for specific detection of fusion proteins that have an oligohistidine domain comprising five or six consecutive histidine residues. The antibody does not recognize tetrahistidine domains or domains in which the histidine string is interrupted by another amino acid. The antibody binds to the oligohistidine domain regardless of the surrounding amino acid context and even when the group is partially hidden, although subtle differences in the amino acid context may change the sensitivity limit for a particular fusion protein. This antibody can be used to detect oligohistidine fusion proteins on western blots, dot blots or colony blots, or in tissues.
5Xhis; Histidine 5X; pentahistidine