RESONANCE RAMAN STUDIES OF RHODOPSIN & RELATED PIGMENTS

我们希望了解视觉传导的分子基础。 特别是，我们打算深入研究(1)关键之光 化学能量转换步骤，将视紫红质转化为视紫红质 转换，以及(2)转导化学的第一步 导致杆状细胞超极化的级联反应 由兴奋的视紫红质催化。为了实现这些目标 目标，我们在这里提出了几个实验，使用状态 最先进的光谱技术，产生非常详细的 分子信息。共振拉曼和非常快 (亚皮秒和皮秒)吸收和荧光 将技术用于研究视紫红质为视紫红质 光反应。章鱼的共振拉曼光谱 视紫红质和底紫红质，并进行同位素标记 衍生物，以及昆虫视紫红质，通心粉，将 是为了看看分子概念是否发展了 因为研究得很好的牛系统可以推广到不同的 物种。视紫红质向视紫红质的转变还没有 以动力学方式分解。关于质子是否 视紫红质与视紫红质的易位 光反应及其分子动力学的理解 只有通过动力学测量才能获得台阶。我们相信 我们的0.2PSEC吸收光谱仪应该能够分辨 这是关键一步。这份提案中描述的最新颖的工作是 非常灵敏的经典拉曼差分法的应用 我们实验室最近开发的技术，以获得 转导蛋白与GDP和GTP结合时的拉曼光谱，T. 交换反应T.GDP GTP生成T.GTP GDP，催化 被激发的视紫红质，是放大光的第一步 吸收事件。结合的GDP和GTP的拉曼光谱 应该会提供大量的信息来说明 发生了。

We wish to understand the molecular basis of visual transduction. In particular, we intend to study in depth (1) the key light to chemical energy conversion step, the rhodopsin to bathorhodopsin transition, and (2) the first steps in the transducin chemical cascade reaction leading to rod cell hyperpolarization which is catalyzed by excited rhodopsin. In order to accomplish these goals, we propose here several experiments employing state-of- the-art spectroscopic techniques which yield very detailed molecular information. Resonance Raman and very fast (subpicosecond and picosecond) absorption and fluorescence techniques will be used to study the rhodopsin to bathorhodopsin photoreaction. The resonance Raman spectra of octopus rhodopsin and bathorhodopsin, and isotopically labelled derivatives, and the insect rhodopsin, Ascalaphus macaronius, will be obtained in order to see if the molecular concepts developed for the well studied bovine system can be generalized to different species. The rhodopsin to bathorhodopsin transition has not been kinetically resolved. Knowledge of whether or not proton translocation accompanies the rhodopsin to bathorhodopsin photoreaction and understanding the molecular dynamics of this step can only be obtained by kinetic measurements. We believe our 0.2 psec absorption spectrometer should be able to resolve this key step. The most novel work described in this proposal is the application of very sensitive classical Raman difference techniques, recently developed in our laboratory, to obtain the Raman spectra of GDP and GTP when bound to transducin, T. The exchange reaction T.GDP+GTP yields T.GTP+GDP, catalyzed by excited rhodopsin, is the first step in amplification of the light absorption event. The Raman spectra of bound GDP and GTP should provide a great deal of information on how the reaction takes place.