Structures of the entire human opioid receptor family.
Wang, Y., Zhuang, Y., DiBerto, J.F., Zhou, X.E., Schmitz, G.P., Yuan, Q., Jain, M.K., Liu, W., Melcher, K., Jiang, Y., Roth, B.L., Xu, H.E.(2023) Cell 186: 413-427.e17
- PubMed: 36638794 
- DOI: https://doi.org/10.1016/j.cell.2022.12.026
- Primary Citation of Related Structures:  
8F7Q, 8F7R, 8F7S, 8F7W, 8F7X - PubMed Abstract: 
Opioids are effective analgesics, but their use is beset by serious side effects, including addiction and respiratory depression, which contribute to the ongoing opioid crisis. The human opioid system contains four opioid receptors (μOR, δOR, κOR, and NOPR) and a set of related endogenous opioid peptides (EOPs), which show distinct selectivity toward their respective opioid receptors (ORs). Despite being key to the development of safer analgesics, the mechanisms of molecular recognition and selectivity of EOPs to ORs remain unclear. Here, we systematically characterize the binding of EOPs to ORs and present five structures of EOP-OR-G i complexes, including β-endorphin- and endomorphin-bound μOR, deltorphin-bound δOR, dynorphin-bound κOR, and nociceptin-bound NOPR. These structures, supported by biochemical results, uncover the specific recognition and selectivity of opioid peptides and the conserved mechanism of opioid receptor activation. These results provide a structural framework to facilitate rational design of safer opioid drugs for pain relief.
Organizational Affiliation: 
The CAS Key Laboratory of Receptor Research and the State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China.