Structural Elucidation of Photosynthetic antenna and Its Application for Light Harvesting System.

我们成功地利用金菖蒲（Chloroflexus aurantiacus）和黄菖蒲（Chlorobium tepidum）的光合膜制备了光合天线。采用固态高分辨率（交叉极化/偏角旋转（CP/MAS）） ^<13>CNMR对分离的天线叶绿体进行了研究。我们已经澄清了细菌叶绿素c的配位状态，BChl c之间的相互作用以及BChl c与周围氨基酸残基在天然状态和原位的相互作用。我们用有机溶剂萃取和高效液相色谱法纯化了多种BChl c和d衍生物。用一、二维^1H和^<13>C核磁共振和红外光谱测定了颜料的结构。用皮秒时间分辨荧光光谱法研究了天线系统内以及天线与反应中心之间的激发能传递。研究结果为阐明天线系统收集和利用光能的结构和机理提供了依据。首次用结构明确的纯化BChl c和d衍生物制备了与天然叶绿体天线相似的模型天线体系。利用CP/MAS^<13>C NMR和FTIR对合成模型天线的结构进行了研究。这些研究为建立模型天线系统和有效利用光能提供了指导。

We have succeeded in preparing photosynthetic antennas from photosynthetic membranes of Chloroflexus aurantiacus and Chlorobium tepidum. The isolated antenna chlorosomes were studied by a solid state high resolution (cross polarization / magic angle spinning (CP/MAS)) ^<13>CNMR. We have clarified the cooridation states of the bacteriochlorophyll (BChl) c's, the interactions between BChl c's and the interactions of BChl c's with surrounding amino acid residues in native states and in situ. We have purified various BChl c and d derivatives by extraction with organic solvent and HPLC. The structures of the pigments were determined with one and two dimensional ^1H and ^<13>C NMR and FTIR. Excitation energy transfers in the antenna systems and also between the antennas and reaction centers were investigated with a pico-second time resolved fluorescence spectrometry. The results gave an evidence to elucidate the structures and mechanisms for the antenna systems to collect and utilize the light energy. The model antenna systems which resembled the native chlorosome antenna have been prepared for the first time from the purified BChl c and d derivatives with clarified structures. The organization of the synthesized model antenna were investigated with CP/MAS^<13>C NMR and FTIR. These investigations offered a guide line to construct a model antenna system and to utilize light energy efficiently.