Figure 5

FRET-efficiencies of SNAP-labeled MOR constructs plotted as a function of acceptor intensity (i.e., expression level) before photobleaching. CD28 (blue color) is used as reference dimer whereas β1AR (orange color) is used as reference monomer. Wild-type MOR (green color), as well as inactive MOR mutant T279D (purple color) and constitutively active MOR mutant T279K (red color), all show an unspecific increase in FRET efficiencies.