Kim Kookjoo, Li Huan, Yuan Qi, Melville Zephan, Zalk Ran, des Georges Amédée, Frank Joachim, Hendrickson Wayne A, Marks Andrew R, Clarke Oliver B
Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA.
Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY 10032, USA.
bioRxiv. 2024 Oct 24:2024.10.21.619409. doi: 10.1101/2024.10.21.619409.
Malignant hyperthermia (MH) is a life-threatening pharmacogenetic condition triggered by volatile anesthetics, which activate pathogenic RyR1 mutants. The small molecule therapeutic dantrolene has long been used to treat MH. However, the binding site and mechanism of dantrolene remain unclear. Here, we present cryo-EM structures of RyR1 bound to dantrolene and the MH trigger agent 4-chloro-m-cresol (4CmC), revealing the dantrolene and 4CmC binding sites in atomic detail. Dantrolene binds stacked with ATP or ADP in the RY12 domain at the corner of the receptor, inducing a conformational change in this domain which is allosterically coupled to pore closure. Functional analyses revealed that ATP or ADP was required for dantrolene inhibition, and a single point mutation that disrupts the peripheral ATP binding site abolished ATP/ADP-dependent dantrolene inhibition. Strikingly, in the absence of dantrolene, this site selectively binds two ADP molecules, suggesting a possible role in ATP/ADP ratio sensing.
恶性高热（MH）是一种由挥发性麻醉剂引发的危及生命的药物遗传学疾病，挥发性麻醉剂会激活致病性的兰尼碱受体1（RyR1）突变体。小分子治疗药物丹曲林长期以来一直用于治疗MH。然而，丹曲林的结合位点和作用机制仍不清楚。在此，我们展示了与丹曲林和MH触发剂4-氯间甲酚（4CmC）结合的RyR1的冷冻电镜结构，以原子细节揭示了丹曲林和4CmC的结合位点。丹曲林与ATP或ADP堆叠结合在受体角落处的RY12结构域中，诱导该结构域发生构象变化，该变化与孔道关闭发生变构偶联。功能分析表明，丹曲林抑制需要ATP或ADP，破坏外周ATP结合位点的单点突变消除了ATP/ADP依赖性丹曲林抑制作用。引人注目的是，在没有丹曲林的情况下，该位点选择性结合两个ADP分子，提示其在ATP/ADP比率传感中可能发挥作用。
