High yield bacterial expression and purification of active recombinant PA28alphabeta complex.

The PA28 complexes (also termed REG or 11S complexes) are described as activators of the 20S proteasome, a major intracellular protease in eukaryotic cells. They bind to the ends of the barrel-shaped 20S proteasome, and activate its peptidase activities. The interferon gamma inducible PA28alphabeta, made of the two related subunits PA28alpha and beta, is under sustained investigation as it plays important roles in the production by the proteasome of class I antigen peptides.