Primary Processes in Fe-S-Type Photosynthetic Reactions Centers

9727607布兰肯希普这项研究的目的是扩大目前对光合作用反应中心中能量捕获过程、初级光化学和早期次级电子转移反应的理解，这些反应中心包含FeS中心作为早期电子受体。将要研究的特殊系统包括原始无氧生物的反应中心，即已知的幽门杆菌，以及产氧光合作用生物的光系统I。这项工作的总体目标之一是将在光谱分析中观察到的一些色素与最近在光系统I的X射线结构中观察到的色素相关联。具体拟议的实验包括，在光系统I的蓝色光谱区域进行皮秒瞬时吸光度测量，在苯酚结合区和P700结合区研究光系统I突变体，对光系统I进行二色性实验，以及利用EPR和皮秒时间尺度瞬时吸收光谱研究幽门螺杆菌中的二次电子转移反应。这些实验将对含有完整核心天线颜料的反应中心的能量捕获过程提供新的见解，并将有助于识别和表征这些系统中的一些早期电子受体，包括叶绿素、苯二酚和FeS中心。这项工作的目标是了解植物和其他光合作用生物如何将阳光能量转化为化学能。这个项目的目的是提供关于一类光合作用复合体中能量储存的化学机制的详细知识，这类化合物还没有被很好地理解。在理解在这一基本生物过程中起作用的基本科学原理方面的进展可能最终导致人工能量存储系统的发展。人工系统可能会减少我们对化石燃料的依赖，减少污染物和温室气体的排放。另一个可能的好处是将这些知识用于开发有助于满足我们的食物和纤维需求的改良植物。***

9727607 Blankenship The objective of this research is to extend the current understanding of the energy trapping processes, primary photochemistry and early secondary electron transfer reactions in photosynthetic reaction centers that contain FeS centers as early electron acceptors. The particular systems that will be studied include reaction centers from the primitive anoxygenic organisms known as heliobacteria as well as Photosystem I of oxygenic photosynthetic organisms. One of the overall goals of the work is to correlate some of the pigments observed in spectroscopic studies with pigments observed in the recent X-ray structure of Photosystem I. Specific proposed experiments include, picosecond transient absorbance measurements in the blue spectral region in Photosystem I, studies on Photosystem I mutants in the quinone-binding region and the P700 binding region, dichroism experiments on Photosystem I and investigation of secondary electron transfer reactions in heliobacteria monitored using EPR and picosecond timescale transient absorbance spectroscopy. These experiments will give new insights into the energy trapping process in reaction centers that contain integral core antenna pigments and will help to identify and characterize some of the early electron acceptors in these systems, including chlorophylls, quinones and FeS centers. The goal of this work is to understand how plants and other photosynthetic organisms convert the energy of sunlight into chemical energy. This project is designed to give detailed knowledge of the chemical mechanism of energy storage in a class of photosynthetic complexes that is not well understood. Advances in understanding the basic scientific principles at work in this essential biological process may ultimately lead to the development of artificial energy storage systems. The artificial systems may decrease our dependence on fossil fuels and reduce emission of pullutants and greenhouse gases. Another possible benefit is the use of this knowledg e in the development of improved plants that will help meet our food and fiber needs. ***