Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China.
School of Pharmacy, Hebei Medical University, Shijiazhuang 050017, China.
J Phys Chem B. 2024 Sep 12;128(36):8651-8661. doi: 10.1021/acs.jpcb.4c03731. Epub 2024 Aug 29.
The norepinephrine transporter (NET) plays a pivotal role in recycling norepinephrine (NE) from the synaptic cleft. However, the structures referring to the conformational heterogeneity of NET during the transport cycle remain poorly understood. Here, three structural models of NE bound to the orthosteric site of NET in outward-open (OO), outward-occluded (OC), and inward-open (IO) conformations were first obtained using the multistate structures of serotonin transporter as templates and further characterized through Gaussian-accelerated molecular dynamics and free energy reweighting. Analysis of the structures revealed eight potential allosteric sites on the functional-specific states of NET. One of the pharmacologically relevant pockets located at the extracellular vestibule was further verified by simulating the binding behaviors of a clinical trial drug χ-MrIA that is allosterically regulating NET. These structural and energetic insights into NET advanced our understanding of NE reuptake and paved the way for discovering novel molecules targeting the allosteric sites.
去甲肾上腺素转运体（NET）在将去甲肾上腺素（NE）从突触间隙中再循环中起着至关重要的作用。然而，在转运循环过程中，与 NET 构象异质性相关的结构仍知之甚少。在这里，首先使用 5-羟色胺转运体的多态结构作为模板，获得了与 NET 的正位结合的三种结构模型：向外开放（OO）、向外阻塞（OC）和向内开放（IO）构象，然后通过高斯加速分子动力学和自由能再加权进一步进行了特征描述。对结构的分析揭示了 NET 功能特定状态上的八个潜在变构位点。位于细胞外前庭的一个具有药理学相关性的口袋通过模拟临床试验药物 χ-MrIA 的结合行为得到了进一步验证，χ-MrIA 是一种变构调节 NET 的药物。这些关于 NET 的结构和能量的深入了解，促进了我们对 NE 再摄取的理解，并为发现靶向变构位点的新型分子铺平了道路。
