Fig. 8.

Comparison of predicted binding site pharmacophores for three ligands bound to active-state β₂AR. (A) C1-S binding sites include HB (pink arrows) to Ser203^5.42 and Asn312^7.39; SB (purple line) to Asp113^3.32; and Pi–Pi stacking at Phe193^ECL2 with an internal aromatic bond (green line). (B) The binding site of C1-R is characterized primarily by the SB to Asp113^3.32. (C) Epinephrine binding sites include HB to Ser203^5.42, Ser207^5.46, Asn293^6.55, Asn312^7.39 and Asp113^3.32; SB to Asp113^3.32; cation–π interaction with Phe193^ECL2; and a π-stacking interaction with Phe290^6.52.