Protein-Membrane Organization and Function: Ion Channels

蛋白质膜组织和功能：离子通道

• 批准号: 9313835
• 负责人: James Hinton
• 金额: $ 24万
• 依托单位: University of Arkansas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-15 至 2000-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9313835&HistoricalAwards=false
• 关键词: Protein; Membrane; Organization; Function; Ion

9313835 Hinton The transport of matter through membranes is a basic phenomenon of life. All organisms are separated from their environment by special membrane barriers which control the exchange of matter with their surroundings and act as an electrical resistor. In addition, nearly all life processes are intimately involved with membrane function. Thus, membrane functions play a central role in communication between and within cells, in the transformation of metabolic energy into osmotic, electrical, and to some extent mechanical work. In living cells an electrical potential difference exists between the cytoplasma and the extracellular medium because of the unequal distribution of ions on both sides of the plasma membrane surrounding the cell. The cell membranes are equipped with special transport mechanisms which accelerate the passage of ions across the lipid barrier. An understanding of these transport mechanisms is a vital link to the ultimate goal of the comprehension of some types of membrane function. The transport of monovalent cations, such as Li+, Na+, and K+, through cell membranes plays a key role in many different physiological processes. These processes involve the maintenance of transmembrane potential, conduction of nerve impulses down the axon and across the neuromuscular junction and the differentiation and growth of cells. There are relatively few physical techniques available for the characterization of the interaction of monovalent cations with biological molecules responsible for cation transport. However, nuclear magnetic resonance spectroscopy (NMR) has proven to be an exceptionally powerful technique for the study of the transport process and the molecular systems responsible for the transport. NMR methods may be used to determine the 3-dimensional structure of the channel, to determine the thermodynamic parameters for the integration of transport system into membranes, to determine the thermodynamic parameters for the binding of the cations to the channel and for determining the activation enthalpy for the transport process. %%% The objectives for the requested funding period involve the use of multinuclei multidimensional NMR spectroscopy, structure determination through the use of NMR determined proton distance restrained molecular dynamics/simulated annealing and peptide synthesis to: (1) study the effect of single amino acid substitution on channel structure, the integration into a membrane as a channel, cation binding and transport in the channel system, gramicidin. The objective is to determine how the structure is related to channel formation and selective monovalent cation transport; (2) to obtain the structure of the model membrane bound individual helical components of the pentameric helical bundle that is related to the nicotinic acetylcholine receptor channel. Monovalent cation binding and transport selectivity will also be investigated. ***

9313835 Hinton物质通过膜的运输是生命的基本现象。 所有生物都通过特殊的膜屏障与环境分开，这些膜屏障控制物质与周围环境的交换并充当电阻。 此外，几乎所有生命过程都与膜功能密切相关。 因此，膜功能在细胞之间和内部之间的通信，代谢能将其转化为渗透，电气以及在某种程度上机械工作中起着核心作用。 在活细胞中，由于细胞和细胞外培养基之间存在电势差，因为离子在细胞周围的质膜两侧的分布不相等。 细胞膜配备了特殊的运输机制，可加速离子在整个脂质屏障中的通过。 对这些运输机制的理解是与理解某些类型的膜功能的最终目标的重要联系。 单价阳离子（例如Li+，Na+和K+）通过细胞膜的运输在许多不同的生理过程中起着关键作用。 这些过程涉及跨膜电位的维持，神经冲动沿轴突和神经肌肉连接的传导以及细胞的分化和生长。 相对较少的物理技术可用于表征单价阳离子与负责阳离子运输的生物分子的相互作用。 然而，事实证明，核磁共振光谱（NMR）是一种非常强大的技术，用于研究运输过程和负责运输的分子系统。 NMR方法可用于确定通道的3维结构，以确定将传输系统整合到膜中的热力学参数，以确定阳离子结合到通道的热力学参数并确定运输过程的激活焓。 %% %%通过使用NMR确定的NMR确定的质子距离约束分子动力学/模拟退火和模拟肽合成来使用多维数多维的NMR光谱法，结构确定：（1）研究单个氨基酸对通道结构的效果，将传播系统的效果置于谱系中，并将其融合到谱系中。 目的是确定结构与通道形成和选择性单价阳离子传输的关系； （2）获得与烟碱乙酰胆碱受体通道相关的五聚螺旋束的模型膜结合的单个螺旋成分的结构。 单价阳离子结合和运输选择性也将进行研究。 ***