美国俄勒冈健康与科学大学Eric Gouaux和美国国立卫生研究Kenneth A. Jacobson共同合作，近期取得重要工作进展。他们研究提出了人类多巴胺转运蛋白的结构及其抑制机制。相关研究成果2024年8月7日在线发表于《自然》杂志上。

据介绍，神经递质多巴胺在情绪、食欲、觉醒和运动中起着核心作用。尽管人类多巴胺转运蛋白（hDAT）在大脑生理和功能中具有重要作用，并且是非法和治疗药物的靶标，但它被小分子和Zn²⁺抑制的机制还没有高分辨率的结构背景。

研究人员确定了hDAT与竞争性抑制剂和可卡因类似物β-CFT、非竞争性抑制剂MRS7292和Zn²⁺的三元复合物的结构。研究人员展示了β-CFT如何占据中心位置，大约在膜的一半，使转运蛋白稳定在向外开放的构象中。

MRS7292与一个结构上未表征的变构位点结合，该变构位点邻近细胞外前庭，隔离在细胞外环4（EL4）下方，邻近跨膜螺旋1b（TM1b），充当楔形物，阻止TM1b的运动和细胞外门的关闭。Zn²⁺ 离子通过将 EL4 与 EL2、TM7 和 TM8 连接起来，进一步稳定了向外的构象，从而提供了关于 Zn²⁺ 如何限制 EL4 相对于 EL2 的运动并抑制运输活性的具体见解。

附：英文原文

Title: Structure of the human dopamine transporter and mechanisms of inhibition

Author: Srivastava, Dushyant Kumar, Navratna, Vikas, Tosh, Dilip K., Chinn, Audrey, Sk, Md Fulbabu, Tajkhorshid, Emad, Jacobson, Kenneth A., Gouaux, Eric

Issue&Volume: 2024-08-07

Abstract: The neurotransmitter dopamine has central roles in mood, appetite, arousal and movement1. Despite its importance in brain physiology and function, and as a target for illicit and therapeutic drugs, the human dopamine transporter (hDAT) and mechanisms by which it is inhibited by small molecules and Zn2+ are without a high-resolution structural context. Here we determine the structure of hDAT in a tripartite complex with the competitive inhibitor and cocaine analogue, (–)-2-β-carbomethoxy-3-β-(4-fluorophenyl)tropane2 (β-CFT), the non-competitive inhibitor MRS72923 and Zn2+ (ref. 4). We show how β-CFT occupies the central site, approximately halfway across the membrane, stabilizing the transporter in an outward-open conformation. MRS7292 binds to a structurally uncharacterized allosteric site, adjacent to the extracellular vestibule, sequestered underneath the extracellular loop 4 (EL4) and adjacent to transmembrane helix 1b (TM1b), acting as a wedge, precluding movement of TM1b and closure of the extracellular gate. A Zn2+ ion further stabilizes the outward-facing conformation by coupling EL4 to EL2, TM7 and TM8, thus providing specific insights into how Zn2+ restrains the movement of EL4 relative to EL2 and inhibits transport activity.

DOI: 10.1038/s41586-024-07739-9

Source: https://www.nature.com/articles/s41586-024-07739-9