ANESTHETIC ALTERATION OF PROTEIN LIPID INTERACTIONS

我们的假设是，膜结构的波动起着重要作用。 在调节膜蛋白功能中的重要作用。 假设 麻醉作用的部位是生物组织的脂质基质， 膜，我们认为，在麻醉的初始事件是改变 这种波动。 这个假设将用凝胶到液体的测试- 单晶中的晶型转变和基于成分的相分离 双层囊泡作为这种波动的模型。 一般的影响 和局部麻醉剂对这些跃迁的平衡性质的影响 将使用量热和光谱技术进行研究。 将特别强调对下列方面的定量评价： 麻醉诱导的熔化温度和热形状的变化 与热致转变相关的容量函数。 前 参数是麻醉剂在药物中的不同溶解度的量度。 凝胶和液晶状态;后一个参数与 不同分子的分布的细节（例如簇大小） 脂类的种类。 转型的动力也将是 研究使用一种新的，体积扰动，动态量热计。 一个 这项研究的一个重要方面是调查麻醉剂如何 改变磷脂酶A2的囊泡表面活化， 似乎与脂质结构波动密切相关。 这些 结构波动取决于温度、脂质组成和 可以诱导酶自发活化的反应产物。 这是特别重要的，因为所有的膜成分可以 潜在地改变膜波动。 拟议的实验将 提供一个热力学和动力学信息库， 定义脂质-酶系统，允许构建特异性定量 描述麻醉作用的陈述， 膜结构和膜介导的蛋白质功能。 反应微量热法，差示扫描量热法，荧光 光谱和pH统计技术将用于这项调查。 该实验室在这些技术方面拥有不同寻常的专业知识， 通过其他程序，如电子显微镜和核 磁共振 实验工作将辅以计算机 模拟（例如蒙特卡罗计算）描述的模型 综合实验结果。

It is our hypothesis that membrane structural fluctuations play an important role in the modulation of membrane-protein 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. This hypothesis will be tested using the gel to liquid- crystalline transition and compositional-based phase separations in single bilayer vesicles as models for such fluctuations. The effects of general and local anesthetics on the equilibrium properties of these transitions will be investigated using calorimetric and spectroscopic techniques. Particular emphasis will be placed on quantitative evaluation of the anesthetic-induced changes in the melting temperature and shape of the heat capacity function associated with the thermotropic transitions. The former parameter is a measure of the differential solubility of the anesthetic in the gel and liquid-crystalline states; the latter parameter is related to the details (e.g. cluster size) of the distribution of distinct molecular species of the lipids. The dynamics of the transitions will also be investigated using a novel, volume perturbation, dynamic calorimeter. An important aspect of this study is the investigation of how anesthetics alter the vesicle-surface activation of the enzyme phospholipase A2 which appears to be strongly coupled to lipid structural fluctuations. These structural fluctuations depend upon temperature, lipid composition and reaction products which can induce spontaneous activation of the enzyme. This is particularly important since all membrane constituents can potentially alter membrane fluctuations. The proposed experiments will provide a library of thermodynamic and kinetic information related to define lipid-enzyme system, allowing 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, fluorescence spectroscopy, and pH stat techniques will be used in this investigation. This laboratory possesses unusual expertise in these techniques, which will be complemented by other procedures such as electron microscopy and nuclear magnetic resonance. The experimental work will be supplemented by computer simulation (e.g. Monte Carlo calculations) of the models describing the composite of the experimental results.