CONFORMATIONAL DYNAMICS IN ION CHANNEL SELECTIVITY AND GATING

离子通道选择性和门控中的构象动力学

• 批准号: 9133430
• 负责人: Katherine Anne Henzler-Wildman
• 金额: $ 29.72万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9133430
• 关键词: Action Potentials; Affect; Asthma; Bacillus cereus; Behavior; Binding; Binding Sites; Biochemistry; Biological; Biological Models; Biological Process; Biophysics; Cations; Cells; Charge; Chemicals; Communication; Complex; Coupling; Cyclic Nucleotides; Dehydration; Disease; Electrophysiology (science); Epilepsy; Health; Hydration status; Investigation; Ion Channel; Ions; Kinetics; Length; Ligands; Measurement; Measures; Membrane; Membrane Potentials; Membrane Proteins; Methods; Modeling; Molecular; Mutation; Myocardial dysfunction; N-terminal; Neurologic Dysfunctions; Physiological; Population; Potassium Channel; Process; Property; Protein Dynamics; Resolution; Rest; Role; Site; Slide; Sodium Chloride; Structure; Techniques; Testing; Thermodynamics; Time; Vertebral column; Water; base; biophysical properties; hearing impairment; in vivo; interest; mutant; simulation; tool; Action Potentials; Affect; Asthma; Bacillus cereus; Behavior; Binding; Binding Sites; Biochemistry; Biological; Biological Models; Biological Process; Biophysics; Cations; Cells; Charge; Chemicals; Communication; Complex; Coupling; Cyclic Nucleotides; Dehydration; Disease; Electrophysiology (science); Epilepsy; Health; Hydration status; Investigation; Ion Channel; Ions; Kinetics; Length; Ligands; Measurement; Measures; Membrane; Membrane Potentials; Membrane Proteins; Methods; Modeling; Molecular; Mutation; Myocardial dysfunction; N-terminal; Neurologic Dysfunctions; Physiological; Population; Potassium Channel; Process; Property; Protein Dynamics; Resolution; Rest; Role; Site; Slide; Sodium Chloride; Structure; Techniques; Testing; Thermodynamics; Time; Vertebral column; Water; base; biophysical properties; hearing impairment; in vivo; interest; mutant; simulation; tool

 DESCRIPTION (provided by applicant): Ion channels control both the resting membrane potential and the action potential in cells. As a result, improper physiological function of ion channels leads to a wide variety of disease states, including cardiac and neurological dysfunction, epilepsy, asthma, hearing loss, and others. Proper ion channel function requires appropriate ion selectivity and channel gating to control ion flux across biological membranes. However, our understanding of these fundamental properties of ion channels is still incomplete because they arise from a complex interplay of structure and dynamics. We will use solution NMR to experimentally test the role of protein dynamics in ion selectivity and gating of the NaK channel from Bacillus cereus solubilized in isotropic bicelles. NaK is an ideal model system because small mutations can shift its selectivity; its structure is similar to eukaryotic potassium channel pore domains, particularly biomedically important cyclic nucleotide gated and HERG potassium channels; and it is highly stable and amenable to structural and biophysical characterization. NMR provides a unique method to simultaneously and quantitatively probe ion channel structure and dynamics with site-specific resolution. The ability of NMR to measure dynamics on diverse timescales and detect transient and lowly populated states allows us to experimentally evaluate the role of protein dynamics on processes ranging from ion selectivity to channel gating. In this proposal we will use NMR studies of NaK to test three aims: Does selectivity arise from cooperative effects of ion binding on backbone dynamics? How does the N-terminal M0 helix regulate NaK gating? What structural and dynamic features allow allosteric communication between the selectivity filter and inner gate in potassium channels?

 描述（由适用提供）：离子通道控制静息膜电位和细胞中的作用电位。结果，离子通道的身体功能不当会导致多种疾病状态，包括心脏和神经功能障碍，癫痫，哮喘，听力损失等。正确的离子通道功能需要适当的离子选择性和通道门控以控制生物学机制的离子通量。但是，我们对离子通道的这些基本特性的理解仍然是不完整的，因为它们是由结构和动力学的复杂相互作用引起的。我们将使用溶液NMR来实验测试蛋白质动力学在离子选择性和从蜡状芽孢杆菌中溶解在各向同性双塞子中的NAK通道中的作用。 NAK是理想的模型系统，因为小突变可以改变其选择性。它的结构类似于真核钾 通道孔域，尤其是生物医学上重要的环状核卫星门控和HERG钾通道；它是高度稳定的，并且可以接受结构和生物物理表征。 NMR提供了一种独特的方法，可以简单地和定量探针离子通道结构和动力学分辨率。 NMR测量潜水时标和检测瞬时和较低人口的状态的动力学的能力使我们能够通过实验评估蛋白质动力学在离子选择性到通道门控的过程中的作用。在此提案中，我们将使用NAK的NMR研究来测试三个目标：选择性是否来自离子结合对骨干动力学的辅导影响？ N末端M0螺旋如何调节NAK门控？哪些结构和动态特征允许钾通道中的选择性过滤器和内门之间的变构通信？