The tandem affinity purification (TAP) method: A general procedure of protein complex purification

Identification of components present in biological complexes requires their purification to near homogeneity. Methods of purification vary from protei n to protein, making it impossible to design a general purification strateg y valid for all cases. We have developed the tandem affinity purification ( TAP) method as a tool that allows rapid purification under native condition s of complexes, even when expressed at their natural level. Prior knowledge of complex composition or function Is not required. The TAP method require s fusion of the TAP tag, either N- or C-terminally, to the target protein o f interest. starting from a relatively small number of cells, active macrom olecular complexes can be isolated and used for multiple applications. Vari ations of the method to specifically purify complexes containing two given components or to subtract undesired complexes can easily be implemented. Th e TAP method was initially developed in yeast but can be successfully adapt ed to various organisms. Its simplicity, high yield, and wide applicability make the TAP method a very useful procedure for protein purification and p roteome exploration. (C) 2001 Academic Press.