Figure 5.

TR-FRET binding assays using HEK293TR-hCB₁R cell membranes. (A) Observed association curves of TAMRA probe 29 to hCB₁R. (B) Saturation binding analysis of 29 to hCB₁R after 60 min. (C) Competition binding using 29 (300 nM) as a tracer with increasing concentrations of CB₁R ligand 6 and HU210. (D) Competition binding using NBD probe 28 (60 nM) as a tracer with increasing concentrations of CB₁R ligand 6 and HU210. Kinetic and equilibrium data were fitted to the equations described in the Supporting Information to calculate K_D, k_on, and k_off values for fluorescent and unlabeled ligands. Data are presented as mean ± SEM, N = 3.