Fig. 7.

Model of NAM interaction and effect of β₂AR mutation on NAM-mediated inhibition of β-arrestin recruitment. (A) Best molecular model of DFPQ showing key residue contacts in the β₂AR identified by mutagenesis. The all-atom consensus model of DFPQ is shown in gray. The β₂AR residue side chains are shown for the three mutations E122W, V129L, and M156T with the strongest effects on NAM activity. Concentration–activity curves for inhibition of ISO-induced β-arrestin recruitment by DFPQ, AP-7-168, and AP-7-203 at the β₁AR and β₂AR were compared with mutants of residues E122 (B); V129 (C) and M156 (D) of the β₂AR. Data are normalized to 1 μM ISO and are the mean % ± SEM, n = 3.