D4 dopamine receptor high-resolution structures enable the discovery of selective agonists

A strategy for drug discovery Dopamine receptors are G protein-coupled receptors implicated in many neurological disorders. Different families of dopamine receptors are involved in different signaling pathways, so specificity is a key goal of therapeutics. Wang et al. present high-resolution crystal structures of the DRD4 dopamine receptor bound to the antipsychotic drug nemonapride. The high resolution of the structures facilitated ligand docking, and a DRD4-selective agonist was identified by computational screening of a large library, experimental testing of compounds with the best docking scores, and iterative cycles of docking and testing analogs of those compounds. The identified agonist had a high affinity for DRD4 and no measurable affinity for DRD2 or DRD3. Science, this issue p. 381 High-resolution D4 dopamine receptor crystal structures facilitate the discovery of new ligands. Dopamine receptors are implicated in the pathogenesis and treatment of nearly every neuropsychiatric disorder. Although thousands of drugs interact with these receptors, our molecular understanding of dopaminergic drug selectivity and design remains clouded. To illuminate dopamine receptor structure, function, and ligand recognition, we determined crystal structures of the D4 dopamine receptor in its inactive state bound to the antipsychotic drug nemonapride, with resolutions up to 1.95 angstroms. These structures suggest a mechanism for the control of constitutive signaling, and their unusually high resolution enabled a structure-based campaign for new agonists of the D4 dopamine receptor. The ability to efficiently exploit structure for specific probe discovery—rapidly moving from elucidating receptor structure to discovering previously unrecognized, selective agonists—testifies to the power of structure-based approaches.