Type-1 Photochemical Reaction Centers: Paradigm, Variations, and Applications

该项目提出了一个综合的，全面的研究和培训计划，广泛关注环境和能源的主题-通过其对自然光合作用研究的重要基础和应用方面的重点。该研究将在Co-PI Donald A. Bryant和John H.戈尔贝克，他们合作研究自然光合作用超过二十年。该项目的中心“范式”来自于对蓝藻1型光化学反应中心（RC）结构和功能细节的研究。这项工作在环境意义方面的潜在影响包括新发现的耐氧同型二聚体1型RC的生物化学表征（目标1）;确定嗜铁蓝藻中编码光系统I（PS I）亚基的多拷贝基因的功能、环境和潜在进化相关性（目标2）;在蓝藻聚球藻7002模型中利用条件控制的基因表达进行蓝藻类囊体膜和PS I生物发生的研究（Aim 3）。该项目在太阳能方面的潜在影响涉及表征PS I中初级电荷分离的动力学（目标4）。从本文提出的研究中获得的知识的应用，以及在超过20年的NSF支持的Co-PI研究中进行的知识的应用，在PS I分子线构建的拟议开发中是显而易见的，该构建用作光驱动的电子注入装置，以研究氧化还原活性酶中质子耦合的电子转移反应的机制（目标5）。该研究计划的成功完成将显着增加对1型RC中初级电荷分离机制的了解，并且还应为未来开发太阳能捕获和转换设备提供具有启发性的新见解。有很好的理由相信，这可能是可能的，以确定一种无机催化剂，是生物合成的，这将模仿费托反应，但产生的C-C键在298 K和1巴。更广泛的影响这项研究计划的目的是提出优秀的培训机会，将允许合作PI共同指导研究生和本科生的主题，包括微生物生态学，生理学，遗传学、基因组学、生物化学和生物物理学。将这些研究项目合并为一个项目的原因之一是为学生提供更广泛、更好的综合培训，从而使他们能够更全面地思考有关能源和环境的问题。本提案的目的也是以类似的方式组织的，以说明这些项目如何从起源于微生物生态学和环境的研究逻辑地进展到那些牢固基于生物化学和生物物理学的研究。基于他们在自然光合作用，光收集和太阳能转换过程中的综合，广泛的研究兴趣和观点，Co-PI将有助于培养下一代学术和工业科学家，该领域对我们社会的战略利益和长期经济繁荣越来越重要。共同参与者将继续广泛参与科学领域的外联和协同关系。这项工作的重要方面包括致力于让教师和学生在我们的研究计划中完全或主要是本科院校。Co-PI致力于继续其目前对科学领域代表性不足的少数民族学生的培训。最后，还计划在高中和小学开展外联和教育活动。

Intellectual Merit This project presents an integrated, comprehensive research and training program that focuses broadly on the topics of environment and energy - through its focus on important fundamental and applied aspects of research on natural photosynthesis. The research will be conducted jointly in the laboratories of Co-PIs Donald A. Bryant and John H. Golbeck, who have collaborated on research in natural photosynthesis for more than twenty years. The central "paradigm" of this project derives from research to understand the structural and functional details of type-1 photochemical reaction center (RCs) of Cyanobacteria. The potential impact of the work in terms of significance to the environment includes the biochemical characterization a newly discovered, oxygen-tolerant homodimeric Type-1 RC (Aim 1); determining the functional, environmental, and potentially evolutionary relevance of multiple copies of genes encoding Photosystem I (PS I) subunits in an iron-loving cyanobacterium, (Aim 2); conducting studies of cyanobacterial thylakoid membrane and PS I biogenesis using conditionally controlled gene expression in the model cyanobacterium Synechococcus sp. PCC 7002 (Aim 3). The potential impact of the project in terms of significance to solar energy involves characterizing the dynamics of primary charge separation in PS I (Aim 4). The application of knowledge gained from the studies proposed herein, as well as those conducted during more than 20 years of NSF-supported research by the Co-PIs, is evident in the proposed development of a PS I-molecular wire construct to serve as a light-driven, electron-injection device to study the mechanisms of proton-coupled, electron transfer reactions in redox-active enzymes (Aim 5). The successful completion of this research program will significantly increase an understanding of the mechanism of primary charge separation in type-1 RCs and should also provide instructive new insights for the future development of devices to perform solar energy capture and conversion. There are excellent reasons to believe that it may be possible to identify an inorganic catalyst that is synthesized biologically and that would mimic the Fischer-Tropsch reaction but generate C-C bonds at 298 K and 1 bar.Broader Impacts This research program is designed to present outstanding training opportunities that will allow the Co-PIs to co-mentor graduate and undergraduate students in topics that include microbial ecology, physiology, genetics, genomics, biochemistry, and biophysics. One reason for merging these research programs into a single program was to provide broader, better integrated training to students, whom will thus be able to think more globally about issues concerning energy and the environment. The aims of this proposal were similarly organized in such a way to illustrate how these projects progress logically from studies with their origins in microbial ecology and the environment to those that are firmly based in biochemistry and biophysics. Based upon their combined, broad research interests and perspectives in natural photosynthesis, light harvesting, and solar energy conversion processes, the Co-PIs will help to train the next generation of academic and industrial scientists in a field that is growing in importance to the strategic interests and long-term economic prosperity of our society. The Co-PIs will continue their extensive involvement in outreach and synergistic relationships in science. Important aspects of this effort include a commitment to involving both faculty and students at exclusively or predominantly undergraduate institutions in our research program. The Co-PIs are committed to continuing their current training of students who are members of underrepresented minorities in science. Finally, outreach and educational activities at the high school and grade school levels are planned.