Initial conformation of dopamine in the D2R-Gα_i-complexes.

<p>The backbone of D2R is shown as green ribbon, with important amino acids (indicated as green sticks) that stabilize the ligand dopamine in its initial conformation. Dopamine is represented as orange sticks and stabilized by ionic interactions to D114^3.32 and hydrogen bonds to S193^5.42 and S197^5.46. The second conformation of residue H393^6.55 is shown as red sticks.