Tandem affinity purification

TAP uses two types of agarose beads that bind to the protein of interest and that can be separated from the cell lysate by centrifugation, without disturbing, denaturing or contaminating the involved complexes.

TAP tagging was invented by a research team working in the European Molecular Biology Laboratory in the late 1990s (Rigaut et al., 1999,[2] Puig et al.,2001[3]) and proposed as a new tool for proteome exploration.

The first successful report of using TAP tag technology in plants came in 2004 (Rohila et al., 2004,[6]) There are a few methods in which the fusion protein can be introduced into the host cells.

Whichever method that is being used, it is preferable to maintain expression of the fusion protein as close as possible to its natural level.

An advantage of this method is that there can be real determination of protein partners quantitatively in vivo without prior knowledge of complex composition.

[citation needed] In 2002, the TAP tag was first used with mass spectrometry in a large-scale approach to systematically analyse the proteomics of yeast by characterizing multiprotein complexes.

[9] They used multifaceted mass spectrometry proteomic screens to identify yeast ribosomal complexes and then used TAP tagging to functionally link up all these proteins.

The principle of tandem-affinity purification of multiprotein complexes is not limited to the combination of CBP and Protein A tags used in the original work by Rigaut et al. (1999).

For example, the combination of FLAG- and HA-tags has been used since 2000 by the group of Nakatani [10][11] to purify numerous protein complexes from mammalian cells.