Fluc PCA using purified probes (A) Purification of the Fluc PCA probes. Lane 1, FKBP/N; Lane 2, FRB/N; Lane 3, FKBP/C; Lane 4, FRB/C. (B) PCA using the purified probes at 50 nM each, with/without equimolar rapamycin (Rap). Average and SD values of three samples are shown. (C) Control experiments using non-interacting partners. All the conditions are the same as above.