Fig. 2

Differences between agonistic and antagonistic binding site for β₂-AR. Depicted by the 2D-SIFt profile for agonists (red) and antagonists (blue) (A), and visualized in the crystal structure of β₂-AR, 2RH1 (B). Residues in white are common to both binding modes, blue is unique to antagonist binding and red is unique to agonist binding. For clarity, the 2D-SIFt heatmaps display the per-residue interactions found in more than 30% of the investigated complexes