Structural Determinants of the Biological Activity of Ryanodine

瑞尼定生物活性的结构决定因素

• 批准号: 9817605
• 负责人: William Welch
• 金额: $ 27.24万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2002-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9817605&HistoricalAwards=false
• 关键词: Structural; Determinants; Biological; Activity; Ryanodine

The ryanodine receptor, situated in the triad junction of muscle cells, normally functions as the calcium-release channel that couples depolarization of the sarcolemma with calcium release from the sarcoplasmic reticulum to trigger sarcomere contraction. The receptor is also found in several other cell types where its function in not as clear. The receptor is so-named because of its ability to bind the plant alkaloid, ryanodine, which stabilizes the open channel. The wide distribution of the receptor in muscle and other tissues and the complexity by which channel activity is modulated by a variety of agents strongly suggest a fundamental role for the receptor in cellular function. At present it is not known (a)what the molecular mechanisms are that control channel activity of the receptor, (b) the physiological significance of the receptor in non-muscle cells, and (c) whether there are endogenous ligands that bind to the ryanodine site and affect the channel. The long-term goal of this project is to understand the molecular mechanism of ryanodine modulation of channel activity and the role of the receptor in the intact cell. The basic strategy is to combine directed chemical synthesis of ryanodine analogs, the testing of these analogs for their biological activities, and the computer-assisted modeling of the molecular structure of the receptor based on these activities. The specific aims of the project are the following:1. To synthesize and test ryanodine analogs to determine the minimal structural factors that define their agonist and antagonist properties.2. To map the known high and low affinity ryanodine binding sites and to test their functional properties.3. To map those loci of the binding sites that induce the open and closed states of the channel.The project is a continuing collaborative effort of four laboratories, which will contribute expertise in organic synthesis, membrane electrophysiology, pharmacology and computer modeling.

Ryanodine受体位于肌细胞的三联体交界处，通常作为钙释放通道，将肌膜去极化与肌浆网钙释放结合在一起，触发肌节收缩。在其他几种细胞类型中也发现了该受体，但其功能尚不清楚。该受体之所以被命名，是因为它能够结合植物生物碱兰尼定，兰诺定稳定开放的通道。该受体在肌肉和其他组织中的广泛分布，以及多种药物调节通道活动的复杂性，强烈表明该受体在细胞功能中发挥着重要作用。目前尚不清楚(A)该受体控制通道活性的分子机制是什么，(B)该受体在非肌肉细胞中的生理意义，以及(C)是否存在内源性配体与ryanodine结合并影响该通道。该项目的长期目标是了解兰诺定调节通道活性的分子机制以及受体在完整细胞中的作用。基本策略是将兰诺定类似物的定向化学合成、对这些类似物的生物活性测试以及基于这些活性的受体分子结构的计算机辅助模拟相结合。该项目的具体目标如下：1.合成和测试兰诺定类似物，以确定定义其激动剂和拮抗剂性质的最小结构因素。绘制已知的高亲和力和低亲和力的兰尼定结合位点图谱，并检测其功能性质。绘制导致通道开放和关闭状态的结合位点的基因座图。该项目是四个实验室的持续合作努力，将在有机合成、膜电生理学、药理学和计算机建模方面贡献专业知识。