DRD2 and Parkinson disease: As the treatment of Parkinson’s disease necessitates activation of D2R through agonist binding, we generated a model of the active receptor state using homology modeling based on an agonist-bound cryogenic electron microscopy (cryo-EM) structure of the D3 subtype (Protein Data Bank (PDB) accession code: 7CMV), which is described in detail in ‘Homology modeling of active-state D2 dopamine receptor’ in Methods (Fig. 5a).