Substrate binding and inhibition mechanism of norepinephrine transporter.
Ji, W., Miao, A., Liang, K., Liu, J., Qi, Y., Zhou, Y., Duan, X., Sun, J., Lai, L., Wu, J.X.(2024) Nature 633: 473-479
- PubMed: 39143211 
- DOI: https://doi.org/10.1038/s41586-024-07810-5
- Primary Citation of Related Structures:  
8XB2, 8XB3, 8XB4 - PubMed Abstract: 
Norepinephrine transporter (NET; encoded by SLC6A2) reuptakes the majority of the released noradrenaline back to the presynaptic terminals, thereby affecting the synaptic noradrenaline level 1 . Genetic mutations and dysregulation of NET are associated with a spectrum of neurological conditions in humans, making NET an important therapeutic target 1 . However, the structure and mechanism of NET remain unclear. Here we provide cryogenic electron microscopy structures of the human NET (hNET) in three functional states-the apo state, and in states bound to the substrate meta-iodobenzylguanidine (MIBG) or the orthosteric inhibitor radafaxine. These structures were captured in an inward-facing conformation, with a tightly sealed extracellular gate and an open intracellular gate. The substrate MIBG binds at the centre of hNET. Radafaxine also occupies the substrate-binding site and might block the structural transition of hNET for inhibition. These structures provide insights into the mechanism of substrate recognition and orthosteric inhibition of hNET.
Organizational Affiliation: 
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China.