Chemical Biology of Voltage-Gated Cation Channels

项目摘要 电压门控离子通道在可兴奋的细胞中塑造电信号。现在有了高分辨率的结构 真核细胞的钠、钾和钙通道，从而提供结构足迹来指导功能 假设。在之前的资助期间，我们发现了一个动态区域--振荡器的孔区 钾通道表明依赖于状态的氢键控制着传导 航道的构造。这些观测最近在结构上和计算上都是 已验证。此外，计算研究表明，这个氢键网络的状态，从而 通道的导通状态通过侧链在内束交叉处耦合到通道开口 至主链键合网络沿孔衬层S6段。此外，电压门控通道保持 高价值的药理靶点，钠通道Nav1.7亚型是痛感的基础。遗传 失去Nav1.7可以消除人类的痛觉，成年Nav.17条件性基因敲除动物模型也是如此。 芳基和酰基磺酰胺类化合物靶向的电压敏感结构域(VSD)为 外周表达的钠通道，如Nav1.7，具有低纳摩尔亲和力和衰减性 炎症性和神经性疼痛。人NAV1.7 DIV VSD与GX-936，a的络合物结构 强效的芳基磺酰胺，表明这些化合物利用一种独特的结合模式，从而使药物 同时结合在芳香口袋内并与激活电压的基本残基(R4)接合- 传感器。这些化合物是有用的研究工具，以促进对NAV失活的理解 DIV VSD在这一过程中的作用。此外，推进这种药物结合姿势的化学细节将 使设计的化合物对其他电压传感器具有特定的活性。电压门控钙 通道是二氢吡啶(DHP)的既定药物靶点，最近在 细菌嵌合“CaVAb”的结构--纳米分子DHP结合的工程通道结构 亲和力。然而，目前尚不清楚这种细菌嵌合体是否忠实地复制了 真核Cav.在CAV拮抗的基础上没有预见性信息严重限制了潜力 开发更关键的治疗学临床前筛选方法。 这些目标的成功实现将促进对通道门控的分子理解 并将揭示具有较高治疗价值的临床药物的结合方式。此外，研究工具 在这里生成的将类似地提供给离子通道研究社区。

Project Summary Voltage-gated ion channels shape electrical signals in excitable cells. There are now high-resolution structures of eukaryotic sodium, potassium and calcium channels, thus providing structural footprint to guide functional hypotheses. In the previous funding period we discovered a dynamic region the pore region of Shaker potassium channels which suggest that state-dependent hydrogen bonding controls the conduction conformation of the channel. These observations have recently been structurally and computationally validated. Further, computational studies indicate that the status of this H-bond network, and thus the conductive state of the channel, are coupled to channel opening at the inner bundle crossing though side-chain to main-chain bonding network along the pore-lining S6 segment. Additionally, voltage gated channels remain high-value pharmacological targets, and the sodium channel Nav1.7 isoform underlies pain sensation. Genetic loss of Nav1.7 abrogates pain sensing in humans, as do adult Nav.17 conditional knock-out animal models. Aryl- and acylsulfonamide compounds target the domain IV (DIV) voltage-sensing domain (VSD) of peripherally expressed sodium channels, such as Nav1.7, with low nanomolar affinity and attenuate inflammatory and neuropathic pain. A structure of the human Nav1.7 DIV VSD in complex with GX-936, a potent arylsulfonamide, suggests that these compounds utilize a unique binding mode whereby the drug simultaneously binds within an aromatic pocket and engages a basic residue (R4) of the activated voltage- sensor. These compounds are useful research tools to advance the understanding of NaV inactivation given the role of the DIV VSD in this process. Further, advancing the chemical details of this drug-bound pose will enable the design of compounds specific activity towards other voltage-sensors. Voltage-gated calcium channels are established drug targets of dihydropyridines (DHP), and recently the binding site was captured in a structure of a bacterial chimeric “CaVAb” – an engineered channel construct with nanomolar DHP binding affinity. However, it is not known if this bacterial chimera faithfully replicated the binding chemistry of the eukaryotic CaV. Not having predictive information on the basis for CaV antagonism severely limits the potential to develop of more critical methods for preclinical screens of therapeutics. The successful execution of these aims will advance the molecular understanding of channel gating and will reveal the binding modes of clinical drugs with high therapeutic value. Further, research tools generated here in will be similarly available to the ion channel research community.