ANESTHETIC ALTERATION OF MEMBRANE-PROTEIN INTERACTIONS

膜蛋白相互作用的麻醉改变

• 批准号: 3293128
• 负责人: RODNEY L BILTONEN
• 金额: $ 18.42万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 1991-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3293128
• 关键词: acidity /alkalinity; anesthetics; calorimetry; computer simulation; electron microscopy; enzyme induction /repression; enzyme mechanism; gel; halothane; hydrostatic pressure; liposomes; liquid crystal; membrane activity; membrane lipids; membrane structure; microcalorimetry; nuclear magnetic resonance spectroscopy; phase change; phosphatidylcholines; phospholipase A2; temperature; thermodynamics

It is our hypothesis that membrane structural fluctuations play an important role in the modulation of biological function. Assuming that the site of anesthetic action is the lipid matrix of the biological membrane, we propose that the initial event in anesthesia is alteration of such fluctuations. To test this hypothesis we plan to use the gel-liquid crystalline transition of single bilayer vesicles as a model for such fluctuations and investigate the affect of various anesthetics on the melting temperature, and the average cluster size which is related to the half-width of the transition. Additional studies will include the effect of anesthetics on the kinetics of the transition using a novel volume perturbation, dynamic calorimeter and their effect on lipid-related protein fluorescence noise. A most important aspect of this study will be the investigation of the effect of anesthetics on the activation of pancreatic phospholipase A2 for which we have proposed a model which quantitatively describes data for the lipase's action on phosphatydilcholine vesicle substrates. This model has three key ingredients: the enzyme binds preferentially to the lipid in the gel state; the activation process involves dimer formation on the membrane surface; and the rate of activation is directly proportional to the magnitude of structural fluctuations within the membrane. This latter aspect of the model is particularly important in developing an understanding of mechanisms of enzyme regulation since all membrane constituents can potentially alter membrane fluctuations. The proposed series of experiments will provide a library of data of several thermodynamic and kinetic parameters related to the lipid-enzyme system. This library of information will allow construction of specific quantitative statements describing anesthetic action in terms of its influence on membrane structure and membrane-mediated protein function. Reaction microcalorimetry, differential scanning calorimetry and pH stat technique will be used in this investigation. This laboratory possesses unusual expertise in these techniques which will be complemented by other procedures such as fluorescence measurements, electron microscopy and nuclear magnetic resonance. The experimental worked will be supplemented by computer simulation (e.g. Monte Carlo Calculations) of models describing the composite of the experimental results.

我们的假设是，膜结构的波动起着重要作用。 在调节生物功能中的重要作用。 假设 麻醉剂的作用部位是脑组织的脂质基质。 生物膜，我们建议，在初始事件 麻醉是这种波动的改变。 为了验证这一 假设我们计划使用的凝胶液晶转变的 单双层囊泡作为这种波动的模型， 探讨不同麻醉药对消融的影响 温度，以及与温度相关的平均簇大小。 过渡的半宽度。 其他研究将包括 麻醉剂对使用的过渡动力学的影响 新型体积微扰、动态量热计及其对 脂质相关蛋白质荧光噪声。 最重要的就是不断学习 这项研究的目的是调查 麻醉药对胰腺磷脂酶A2激活的影响 我们提出了一个模型， 脂肪酶对磷脂酰胆碱囊泡底物的作用。 这个模型有三个关键要素： 优先于凝胶状态的脂质;激活 该过程涉及膜表面上的二聚体形成;并且 激活速率与 膜内的结构波动。 后一方面 在开发一个 了解酶的调节机制，因为所有 膜成分可以潜在地改变膜波动。 拟议中的一系列实验将提供一个数据库， 几个热力学和动力学参数相关的 脂酶系统 这个信息库将允许 具体定量陈述的构建 麻醉作用对膜结构的影响 和膜介导的蛋白质功能。 反应微量热法、差示扫描量热法和 本研究将使用pH stat技术。 这 实验室在这些技术方面拥有不同寻常的专业知识， 将通过其他程序，如荧光， 测量，电子显微镜和核磁共振。 实验工作将通过计算机模拟得到补充 (e.g.蒙特卡罗计算）的模型描述的复合材料 实验结果。