Reaction Dynamics in Manybody Chemical Systems : Specificity in Biomolecular Reactions

多体化学系统中的反应动力学：生物分子反应的特异性

基本信息

批准号：
10206206
负责人：
KANDORI Hideki
金额：
$ 15.87万
依托单位：
Kyoto University Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

We have investigated the mechanism of biomolecular chemical reactions. In particular, our main target was cis-trans isomerization and proton transfer reactions in rhodopsins, such as light-driven proton pump bacteriorhodopsin and visual rhodopsin. In rhodopsins, specific reactions in protein environments convert light into protein structural changes, whose relaxation leads to the functional processes. In this project, we approached such specificity from both dynamical and structural aspects. Following results were obtained.As the dynamical aspects, we were able to capture the excited-state dynamics of visual rhodopsin and pharaonis phoborhodopsin, acting as light sensors in our vision and bacterial phototaxis, respectively, by means of femtosecond fluorescence spectroscopy. It was revealed that the protein environment facilitates efficient cis-trans photoisomerization of the retinal chromophore.As the structural aspects, we monitored protein structural changes through inter-atomic vibrations by (Fourier-transform) infrared spectroscopy. In particular, highly optimized experimental set-up allowed to detect the spectral changes in the X-H and X-D stretching frequency regions for the first time. Direct information on the hydrogen-bonding alterations was obtained. The results involved were for bacteriorhodopsin, color visual pigments for green and red lights, and pharaonis phoborhodopsin. These results provide new structural information on the reaction specificity ; on how protein respond to light, and functional processes are driven.

我们研究了生物分子化学反应的机制。特别是，我们的主要目标是顺式传播异构化和呈质子转移反应，例如光驱动的质子泵菌素蛋白和视觉视紫红质。在视紫红素中，蛋白质环境中的特定反应将光转化为蛋白质结构变化，其松弛导致功能过程。在这个项目中，我们从动力学和结构方面都取得了这种特异性。在动力学方面，我们能够通过飞跃的荧光光谱法分别捕获视觉视紫红质和pharaonis phoborhopopsin的激发态动力学，在我们的视觉和细菌光的光中充当光传感器。据揭示，蛋白质环境促进了视网膜发色团的有效顺式TRANS光异构化。在结构方面，我们通过（傅立叶转换）红外光谱通过原子间振动来监测蛋白质的结构变化。特别是，高度优化的实验设置允许首次检测X-H和X-D伸展频率区域的光谱变化。获得有关氢键变化的直接信息。涉及的结果是细菌紫红素，用于绿色和红灯的彩色视觉色素以及pharaonis phoborhopopsin。这些结果提供了有关反应特异性的新结构信息；关于蛋白质对光的反应以及功能过程的驱动。