VIBRATIONAL STUDIES OF ENERGY TRANSDUCING PROTEINS

拟议研究的具体目的是表征 活性颜料的结构和电子性质 能量转换蛋白质。 细菌的光合作用 中心（RC）已被选为研究，因为这类 蛋白质代表了一个原型模型系统， 促进快速电子转移的性质， 距离的数量级为生物膜的宽度。 此外，RC是唯一完整的膜电子转移 蛋白质，其活性物质的大分子排列 已知蛋白质基质中的色素。 校长 将使用的研究工具是共振拉曼（RR） 光谱，虽然红外和电子吸收 光谱学也将发挥重要作用。 半经验 将使用量子力场和norma坐标计算 用于光谱数据的分析。 第一个目标 是为了表征一个 一系列模型化合物。 RR光谱将在一个大的 激发波长的数量，其范围从紫外线 吸收光谱的红色区域。 振动 光谱将被分配，并将获得描述 正常模式 激励配置文件将被构建为 共振增强拉曼带和散射机制将 被确定。 第二个目标是描述 活性颜料的振动和电子性质， RC。 RR光谱将通过激发进入多个 发色团的吸收带，包括 重要的近红外波段。 振动 光谱将通过与模型的光谱进行比较来分配 化合物和蛋白质基质对结构的影响 并评估颜料的电子性质。 的 第三个目标是获得转基因RC的RR谱 为了确定特定的蛋白质残基如何影响 单独的颜料。 总的来说，这些研究旨在 提供了一个更全面的图片之间的关系， 活性色素的物理和功能性质 能量转换蛋白。

The specific aim of the proposed research is to characterize the structural and electronic properties of the active pigments in energy transducing proteins. The bacterial photosynthetic reaction center (RC) has been chosen for study because this class of proteins represents a prototypical model system for investigating the properties which facilitate fast electron transfer over distances on the order of the width of the biological membrane. In addition, the RC is the only integral membrane electron-transfer protein for which the macromolecular arrangement of the active pigments in the protein matrix is known. The principal investigative tool which will be used is resonance Raman (RR) spectroscopy, although infrared and electronic absorption spectroscopy will also play an important role. Semiempirical quantum force field and norma coordinate calculations will be used for the analysis of the spectroscopic data. The first objective is to characterize the vibrational and electronic properties of a series of model compounds. RR spectra will be acquired at a large number of excitation wavelengths which range from the ultraviolet to the red region of the absorption spectrum. The vibrational spectra will be assigned and descriptions will be obtained for the normal modes. Excitation profiles will be constructed for the resonance-enhanced Raman bands and the scattering mechanisms will be determined. The second objective is to characterize the vibrational and electronic properties of the active pigments in RCs. RR spectra will be obtained with excitation into a number of the absorption bands of the chromophores, including the photophysically-important near-infrared bands. The vibrational spectra will be assigned through comparison with those of the model compounds and the influence of the protein matrix on the structural and electronic properties of the pigments will be assessed. The third objective is to obtain RR spectra of genetically modified RCs in order to determine how specific protein residues affect the individual pigments. Collectively, the studies are intended to provide a more comprehensive picture of the relationship between the physical and function properties of the active pigments of energy transducing proteins in general.