Urate is an endogenous product of purine metabolism in the liver. High urate levels in the blood lead to gout, a very common and painful inflammatory arthritis. Excreted urate is reabsorbed in the kidney mainly by URAT1 antiporter, a key target for anti-gout drugs. To uncover the mechanisms of urate transport and drug inhibition, we determined cryo-EM structures of human URAT1 with urate, counter anion pyrazinoate, or anti-gout drugs of different chemotypes — lesinurad, verinurad, and dotinurad. We captured the outward-to-inward transition of URAT1 during urate uptake, revealing that urate binds in a phenylalanine-rich pocket and engages with key gating residues to drive the transport cycle. In contrast to the single binding site for urate, pyrazinoate interacts with three distinct, functionally relevant sites within URAT1, a mechanism that has not yet been observed in other anion antiporters. In addition, we found that while all three drugs compete with substrates and halt the transport cycle, verinurad and dotinurad further hijack gating residues to achieve high potency. These insights advance our understanding of organic anion transport and provide a foundation for designing improved gout therapeutics.

尿酸盐是肝脏嘌呤代谢的内源性产物。血液中的高尿酸盐水平会导致痛风，这是一种非常常见且痛苦的炎症性关节炎。排泄的尿酸盐主要通过 URAT1 抗转运蛋白在肾脏中重吸收，URAT1 抗转运蛋白是抗痛风药物的关键靶点。为了揭示尿酸盐转运和药物抑制的机制，我们确定了人 URAT1 的冷冻电镜结构与尿酸盐、抗阴离子吡嗪酸盐或不同化学型 — 乐司尼达、维利尼达和多替尼达的抗痛风药物。我们捕获了尿酸盐摄取过程中 URAT1 的向外向内转变，揭示了尿酸盐在富含苯丙氨酸的口袋中结合并与关键的门控残基结合以驱动运输循环。与尿酸盐的单个结合位点相反，吡嗪酸盐与 URAT1 内的三个不同的、功能相关的位点相互作用，这种机制尚未在其他阴离子逆向转运蛋白中观察到。此外，我们发现，虽然这三种药物都与底物竞争并停止运输周期，但 verinurad 和 dotinurad 进一步劫持门控残基以实现高效。这些见解促进了我们对有机阴离子转运的理解，并为设计改进的痛风疗法奠定了基础。