U.S.-Japan Cooperative Research: Analysis of the Photosystem I Reaction Center by Resolution-Reconstitution Methods

这一奖项将促进波特兰州立大学化学系John H.Golbeck教授、日本佐治子Teikyo大学Ikegami Isamu教授和日本冈崎国立基础生物学研究所Shigeru Itoh教授之间的继续合作。科学家们正在合作研究绿色植物和蓝藻光合作用发生时的一些基本过程。他们把重点放在由两个光化学系统组成的低势系统(光系统I)上，这两个系统依次参与整个光合作用过程。这个合作项目是基于美国和日本研究人员的联合个人能力，他们可以有选择地移除并放回组成反应中心的叶绿素分子、叶醌分子和铁硫团簇。这种新开发的选择性拆分和重建方案，与科学家实现多肽-蛋白质重新结合的能力相结合，为解决有关光系统I中电子流动途径的长期问题提供了新的机会。通过在重建复合体时省略一些成分，这些亚基的功能可能会得到更好的理解。还可以在重新构建络合物之前对某些组分进行化学改变或交换，以便合成人工中心或修饰中心，并确定效果。此外，使用某些铁和硫同位素将允许进行各种光谱研究，产生关于该络合物的结构信息。

This award will facilitate continued cooperation between Professor John H. Golbeck, Department of Chemistry, Portland State University; Professor Isamu Ikegami, Teikyo University, Sagamiko, Japan; and Professor Shigeru Itoh, National Institute of Basic Biology, Okazaki, Japan. The scientists are collaborating in a study of some of the basic processes occurring when photosynthesis takes place in green plants and cyanobacteria. They are focusing on the lower- potential system (Photosystem I) of two photochemical systems involved sequentially in the overall photosynthetic process. This cooperative project is based on the combined individual abilities of the U.S. and Japanese researchers to remove and then put back, selectively, the chlorophyll molecules, the phylloquinone molecules, and the iron-sulfur clusters that make up the reaction center. This newly developed, selective resolution and reconstitution protocol, combined with the scientists' ability to effect polypeptide - protein rebinding, offers new opportunities to address longstanding questions regarding the pathways of electron flow in Photosystem I. By leaving some of the components out when reconstructing the complex, the function of these subunits may become better understood. Some of the components may also be chemically altered or exchanged before the complex is reconstituted, in order to synthesize artificial or modified centers, and the effect determined. In addition, use of certain iron and sulfur isotopes will permit various spectroscopic studies to be carried out, yielding structural information regarding the complex.