Practice question

Tandem Affinity Purification requires a highly specific, mild protease to release first affinity complex without disrupting interacting partners. Tobacco Etch Virus protease recognizes seven amino acid sequence ENLYFQG and cleaves between Q and G with high specificity under low temperature, physiological pH, and in presence of mild detergents that preserve protein-protein interactions. This orthogonal cleavage site is engineered between Protein A and CBP modules. Trypsin, caspase, and collagenase are more promiscuous or require conditions that would dissociate or degrade complexes, unsuitable for preserving interactome.