Structural Determinants of the Biological Activity of Ryanodine

9317684 Welch Ryanodine是一种植物生物碱，它与一种特定的受体结合，一种细胞内钙释放通道，首先在骨骼肌的三合一连接处被发现。随后，在包括中枢神经系统细胞在内的许多非肌肉细胞中发现了ryanodine受体（RyR）。Ryanodine已被证明是肌肉中钙调节的有力效应器。虽然ryanodine分子是复杂的，但重要的硬脂酸和静电相互作用可以定位于分子的相对较小的特定区域。本项目的总体目标是阐明配体结构与类黄烷类植物的生物活性之间的关系。目标是：(1)开发具有最小结构的生物活性类黄烷，(2)开发影响RyR特性特异性改变的药物，(3)确定哺乳动物骨骼肌ryanodine结合位点，(4)为RyR异构体特异性药物的开发奠定基础，(5)确定内源性效应物。本项目将重点研究兔骨骼肌RyR。方法将是：(1)将开发新的瑞诺定类似物。（II）这些化合物的生物活性将通过测量与RyR结合的配体、使用离子通量和平面脂质双分子层单通道测量来调节RyR的离子通道活性以及对完整细胞的功能影响来评估。（三）类黄烷化合物的构象将通过分子力学、分子动力学和量子力学的方法从共价结构中推导出来。只要有可能，将推导出的构象与核磁共振或晶体学数据进行比较（例如，已经解决了ryanodine的x射线和核磁共振结构）。将对选定的类似物进行比较分子场分析（ComFA），并计算硬脂场和静电场之间的相关性，以辨别生物活性与ryanodine类似物的结构之间的关系。CoMFA的结果将用于设计新的类胡萝卜素，以检验、改进和修正假设。钙离子调节许多关键的细胞功能，如肌肉收缩。细胞内游离钙的水平受到生理控制机制的精确调节。Ryanodine是一种植物生物碱，对细胞内钙的调节有很强的作用，可以作为研究钙调控机制的有用工具。Ryanodine通过与细胞内钙释放通道的特定受体结合而起作用。Ryanodine受体首先在骨骼肌中发现，但也在许多非肌肉细胞中发现，包括中枢神经系统细胞。虽然ryanodine分子是复杂的，但其与受体的功能相互作用可以定位于分子中相对较小的特定区域。本项目的总体目标是阐明类芽素的结构与生物活性之间的关系。这将导致重要的新探针的发展，这将增强我们对细胞钙调节的理解。＊＊＊

9317684 Welch Ryanodine is a plant alkaloid which binds to a specific receptor,an intracellular calcium release channel, first identified at the triad junction of skeletal muscle. Subsequently, ryanodine receptors (RyR) have been found in many non-muscle cells including cells of the central nervous system. Ryanodine has been shown to be a powerful effector of calcium regulation in muscle. Although the ryanodine molecule is complex, important stearic and electrostatic interactions can be localized to relatively small, specific regions of the molecule. The overall goal of this project is to elucidate the relationship between ligand structure and the biological activities of the ryanoids. The aims are to (1) develop biologically active ryanoids with minimal structure, (2) develop agents which effect specific alterations in RyR properties, (3)define the mammalian skeletal muscle ryanodine binding site, (4)lay the groundwork for development of RyR isoform-specific agents and (5) define endogenous effectors. This project will focus on rabbit skeletal muscle RyR. Approaches will be: (I) New ryanodine analogs will be developed. (II) The biological activity of these compounds will be assessed by measurements of ligand binding to the RyR, the modulation of ion channel activity of the RyR using ionic flux and planar lipid bilayer single channel measurements, and functional effects on intact cells. (III) The conformations of the ryanoids will be deduced from the covalent structures by molecular mechanics, molecular dynamics and quantum mechanics. The deduced conformations will be compared to NMR or crystallographic data whenever possible (for example, the X-ray and NMR structures of ryanodine have been solved). A comparative molecular field analysis (ComFA) will be produced for selected analogs, and correlations between the stearic and electrostatic fields computed to discern the relationship between the biological activities and the structure of the ryanodine a nalogs. (IV) The results of the CoMFA will be used to design new ryanoids for testing, refinement and correction of hypotheses. %%% Calcium ion regulates many critical cellular functions such as muscle contraction. The levels of calcium free in cells are precisely regulated by physiological control mechanisms. Ryanodine is a plant alkaloid which has a powerful effect on calcium regulation in cells and can serve as a useful tool in studying calcium control mechanisms. Ryanodine acts by binding to a specific receptor, an intracellular calcium release channel. Ryanodine receptors were first identified in skeletal muscle, but have also been found in many non-muscle cells including cells of the central nervous system. Although the ryanodine molecule is complex, its functional interactions with its receptor can be localized to relatively small, specific regions of the molecule. The overall goal of this project is to elucidate the relationship between the structure and the biological activities of the ryanoids. This will result in the development of important new probes which will enhance our understanding of cellular calcium regulation. ***