AlphaScreen®-based characterization of TAR-R06 interaction. (A) Competition assay setup. The assay was carried out as described in Figure 2A in the presence of untagged R06 (fR06). (B) Competition assay performed as described in A. Increasing concentrations of fR06 were added to the reaction containing 10 nM of dig-R06 and 40 nM of biot-TAR and the AlphaScreen® signal was measured. Data are presented as percent of maximal signal (mean ± SD) and are representative of at least 3 independent experiments carried out in triplicate. (C) Rop binding assay to the TAR-R06 kissing complex. Alphascreen® signal was obtained with a constant amount of biotinylated TAR and digoxiginated R06 (40 nM and 10 nM, respectively) as described in Materials and Methods, in the presence of increasing concentrations of the E. coli Rop protein. Data are representative of 3 independent experiments carried out in triplicate.