The Tag:HBH sequence is a multiple component tag designed for tandem affinity purification and consists of RGSH[[6]] (a nine-amino acid peptide that binds to Ni[2+] chelate resins and can be specifically detected with a monoclonal antibody), a 75-amino acid sequence derived from a Propionibacterium shermanii transcarboxylase that has been shown to be efficiently biotinylated in vivo in yeast and mammalian cells, and a hexahistidine tag (description adapted from PMID:16432255). When fused to the N- or C-terminal end of a protein of interest, a tandem affinity purification tag allows for rapid purification under native conditions of complexes, even when expressed at their natural level. Prior knowledge of complex composition or function is not required (PMID:11403571).