Correlations: Structure-Dynamics-Functions in Channels

相关性：通道中的结构-动力学-函数

• 批准号: 7022975
• 负责人: TIMOTHY A CROSS
• 金额: $ 33.84万
• 依托单位: FLORIDA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7022975
• 关键词: acidity /alkalinity; amantadine; chemical binding; computer simulation; conformation; electrical conductance; electrophysiology; gene mutation; histidine; hydrogen channel; intermolecular interaction; ion channel blocker; ion transport; lipid bilayer membrane; molecular dynamics; nuclear magnetic resonance spectroscopy; protein kinase A; protein structure function; structural biology; tryptophan

DESCRIPTION (provided by applicant): Single and multi-channel conductance measurements, high resolution structural and dynamic characterization by solid-state NMR, and high level computational efforts will lead to structure-function and dynamic-function correlations. These will greatly facilitate our understanding of ion channel conductance, gating and blockage mechanisms, as well as numerous functional details. Previous support through this grant has led to novel correlations for defining functional mechanisms, ion specificity and efficiency in gramicidin A, as well as unique models for opening and closing this channel. Initial mechanistic insights have also been obtained for the M2 H+ channel from influenza A virus. Electrophysiological and NMR studies of the full length M2 protein have illustrated how sensitive membrane proteins are to their bilayer environment and how these structures can have dynamic processes rarely, if ever, observed in water soluble proteins. Here, we propose to characterize structure-dynamic-function correlations in the M2 H+ channel leading to mechanistic understandings. This protein is a proven drug target and it is the first H+ channel to be cloned and expressed. Several key features of this structure include the single transmembrane helix that can be kinked in the presence of a channel blocker, a histidine tetrad that appears to be responsible for H+ selectivity and acid gating, and a tryptophan tetrad that interacts with the histidines, at least in the closed state. High resolution backbone structure and dynamics, as a function of pH, will be obtained for this protein, as well as the pKas of the histidines under various conditions. These efforts will be guided by both modeling and functional characterizations of the protein. This work has broad implications for understanding how, in general, membrane proteins function and how ion specificity, conductance efficiency, gating and blockage can be achieved and characterized all in a lamellar phase lipid environment.

描述（由申请人提供）：单通道和多通道电导测量、固态NMR的高分辨率结构和动态表征以及高水平计算工作将导致结构-功能和动态-功能相关性。这些将极大地促进我们对离子通道电导、门控和阻断机制以及许多功能细节的理解。先前通过该资助的支持已经导致了用于定义短杆菌肽A的功能机制，离子特异性和效率的新型相关性，以及打开和关闭该通道的独特模型。还获得了来自甲型流感病毒的M2 H+通道的初步机制见解。全长M2蛋白的电生理学和NMR研究已经说明了膜蛋白对其双层环境的敏感性，以及这些结构如何具有在水溶性蛋白中很少观察到的动态过程。 在这里，我们提出的M2 H+通道的结构-动态-功能相关性的特点，导致机械的理解。该蛋白是一个被证实的药物靶点，它是第一个被克隆和表达的H+通道。这种结构的几个关键特征包括在通道阻断剂存在下可以扭结的单个跨膜螺旋，似乎负责H+选择性和酸门控的组氨酸四联体，以及至少在闭合状态下与组氨酸相互作用的色氨酸四联体。高分辨率的骨架结构和动力学，作为pH值的函数，将获得该蛋白质，以及在各种条件下的组氨酸的pKa。这些努力将由蛋白质的建模和功能表征来指导。 这项工作具有广泛的意义，了解如何，在一般情况下，膜蛋白的功能，以及如何离子特异性，电导效率，门控和阻断可以实现和特点都在一个层状相脂质环境。