Department of Biophysics and Disease Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang, China.
Nat Commun. 2024 Aug 6;15(1):6654. doi: 10.1038/s41467-024-50975-w.
The ClC-3 chloride/proton exchanger is both physiologically and pathologically critical, as it is potentiated by ATP to detect metabolic energy level and point mutations in ClC-3 lead to severe neurodegenerative diseases in human. However, why this exchanger is differentially modulated by ATP, ADP or AMP and how mutations caused gain-of-function remains largely unknow. Here we determine the high-resolution structures of dimeric wildtype ClC-3 in the apo state and in complex with ATP, ADP and AMP, and the disease-causing I607T mutant in the apo and ATP-bounded state by cryo-electron microscopy. In combination with patch-clamp recordings and molecular dynamic simulations, we reveal how the adenine nucleotides binds to ClC-3 and changes in ion occupancy between apo and ATP-bounded state. We further observe I607T mutation induced conformational changes and augments in current. Therefore, our study not only lays the structural basis of adenine nucleotides regulation in ClC-3, but also clearly indicates the target region for drug discovery against ClC-3 mediated neurodegenerative diseases.
氯离子/质子交换器 ClC-3 无论是在生理还是病理方面都至关重要，因为它可以被 ATP 增强以检测代谢能量水平，而 ClC-3 的点突变会导致人类严重的神经退行性疾病。然而，为什么这种交换器会被 ATP、ADP 或 AMP 差异调节，以及突变如何导致功能获得仍在很大程度上未知。在这里，我们通过低温电子显微镜确定了二聚体野生型 ClC-3 在apo 状态和与 ATP、ADP 和 AMP 复合物中的高分辨率结构，以及在 apo 和 ATP 结合状态下的致病 I607T 突变体。结合膜片钳记录和分子动力学模拟，我们揭示了腺嘌呤核苷酸如何结合到 ClC-3 上，以及 apo 和 ATP 结合状态之间的离子占据情况的变化。我们还观察到 I607T 突变引起的构象变化和电流增强。因此，我们的研究不仅为 ClC-3 中腺嘌呤核苷酸的调节奠定了结构基础，还明确指出了针对 ClC-3 介导的神经退行性疾病的药物发现的目标区域。
