STRUCTURE/FUNCTION STUDIES OF GAP JUNCTIONS

间隙连接的结构/功能研究

• 批准号: 6494989
• 负责人: Thaddeus Andrew Bargiello
• 金额: $ 4.23万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6494989
• 关键词: Xenopus oocyte; alternatives to animals in research; aminoacid; biophysics; chimeric proteins; computer simulation; conformation; electric field; electrophysiology; gap junctions; gene mutation; hereditary motor and sensory neuropathy; membrane channels; membrane proteins; nuclear magnetic resonance spectroscopy; protein structure function; site directed mutagenesis; transfection; voltage gated channel

Gap junctions formed by Cx26 and Cx32 differ in molecular permeability and in sensitivity to transjunctional voltage. These differences will be exploited to define the molecular mechanisms that underlie voltage dependence and ionic fluxes of intercellular and membrane channels formed by proteins of the connexin gene family. In the long term, integration of data from biophysical, molecular genetic, NMR and computer modeling studies will lead to understanding of how conformational changes in this membrane protein and others dynamically relate to their function and how fixed charges modulate ion flux. In the proposed studies the pore-lining sequence of the Cx32 channel will be further defined and the atomic structure of the amino terminus of wild type and mutated Cx32 will be solved by high resolution NMR. The position of the voltage sensor and its relation to the transjunctional electric field will be explored. Studies are proposed to test the hypothesis that the conformational flexibility of a proline kink motif underlies the conformational changes required for voltage dependent gating. Studies are also proposed to distinguish between concerted and individual subunit gating models. Data from molecular and electrophysiological studies of ionic flux will be examined using the electrodiffusive model of Chen and Eisenberg to further define the roles of charged amino acids in determining permeation and selectivity of gap junction channels. X-linked Charcot-Marie-Tooth disease (CMTX) is caused by mutations of human Cx32, and nonsyndromic deafness by mutations of Cx26. Biophysical and molecular studies have shown that changes in permeability of Cx32 are likely to underlie the etiology of CMTX. The proposed studies will advance the basic scientific knowledge required to define the molecular basis of this and other connexin-related diseases, and the biological role of gap junctions.

CX26和CX32形成的间隙连接在分子上有所不同 渗透性和对跨连接电压的敏感性。这些差异 将被利用以定义电压基础的分子机制 由细胞间和膜通道的依赖性和离子通量 连接蛋白基因家族的蛋白质。从长远来看，数据的集成 从生物物理，分子遗传，NMR和计算机建模研究中 导致了解该膜蛋白中构象如何变化 其他人则动态地与其功能以及固定电荷调制的方式有关 离子通量。在拟议的研究中，CX32通道的孔线序列 将进一步定义和野生氨基末端的原子结构 类型和突变的CX32将通过高分辨率NMR解决。位置 电压传感器及其与跨连接电场的关系将 被探索。提出了研究以检验的假设 脯氨酸扭结基序的构象灵活性是构象的基础 电压依赖门控所需的更改。还提出了研究 区分一致的和单个亚基门控模型。来自 将使用离子通量的分子和电生理研究检查 Chen和Eisenberg的电源模型，以进一步定义 在确定间隙连接的渗透和选择性方面，带电的氨基酸 频道。 X连锁的charcot-marie-tooth病（CMTX）是由突变引起的 人类CX32和通过CX26突变的非综合性耳聋。生物物理和 分子研究表明，CX32的渗透性变化可能很可能 CMTX的病因基础。拟议的研究将推进基本 定义该分子和其他分子基础所需的科学知识 连接蛋白相关疾病以及间隙连接的生物学作用。