Protein fragment complementation assay

Patent Granted Protein-fragment complementation assay, or PCA, is a method for the identification of protein–protein interactions in biological systems. It is used in the field of proteomics. In the PCA, the proteins of interest ("Bait" and "Prey") are each covalently linked to incomplete fragments of a third protein (e.g. DHFR, which acts as a "reporter"). Interaction between the "bait" and the "prey" proteins brings the fragments of the "reporter" protein in close enough proximity to allow them to form a functional reporter protein whose activity can be measured.