Figure 3: Molecular determinants of nonselective binding at aminergic receptors.

Structures of a risperidone-bound 5-HT_2AR (light green, PDB: 6A93) and ritanserin-bound 5-HT_2CR (dark green, PDB: 6BQH) show aromatic and hydrophobic interactions with conserved residues forming a hydrophobic cleft deep in the binding pocket, and an ionic bond between the ligand’s protonated amine and the negatively charged side chain of D^3.32. The whole 5-HT_2AR is shown (left) for perspective, with each transmembrane domain numbered.