Real time association of Alexa488-labeled CLIP to (A) 1.6 μM DR1, (B) 0.8 μM DR1, (C) 0.4 μM DR1, (D) 0.2 μM DR1, (E) 0.1 μM DR1, and (F) 0.05 μM DR1 in the presence of a gradient concentration of DM was tracked by fluorescence polarization. (G) Initial rate versus DM concentration for various DR1 concentrations. Initial rate of peptide binding was calculated as the slope of the linear portion of peptide binding curve. (H) Initial rate versus DR1 concentration for various DM concentrations. These experiments are representative of at least three independent experiments.