RII Track-4:NSF: Tracking assembly intermediates of the Photosystem II oxygen-evolving complex

植物和一些微生物利用光合作用有效地将太阳能转化为化学能。然而，在自然光合作用中使用的详细机制尚未完全理解。通过了解生物学如何利用廉价资源（阳光、水、蛋白质、丰富的金属）制造燃料，可以为工业和能源应用的催化策略生成分子水平的蓝图。本项目旨在揭示锰和钙离子与光合作用蛋白质结合形成活性位点的机制，当水被氧化时，分子氧被释放出来。蛋白质样品将在PI的家庭实验室制备，然后使用阿贡国家实验室（ANL）太阳能转换组的先进仪器进行研究。PI和一名研究生将获得光谱技术的实践经验。在该奖学金期间学到的技能将促进在家乡机构开发这种类型的仪器，以提高研究能力，并为未来的学生提供机会。该项目旨在揭示光系统II放氧复合物（OEC）组装的化学机制。这种金属簇是由游离锰离子、钙离子和水原位构建的，而不使用蛋白质转运蛋白或支架。先进的电子顺磁共振（EPR）光谱工具可在ANL将用于表征蛋白质样品制备模拟OEC组装的各个阶段。ANL的主机将提供设施访问，培训，技术专长和数据分析援助。通过这项工作，将产生对OEC组装机制的新见解，并建立PI与ANL主机之间的新合作。PI获得的先进EPR方法的技能和知识将用于改善路易斯安那州的研究基础设施。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plants and some microbes use photosynthesis to efficiently convert solar energy to chemical energy. However, the detailed mechanisms used in natural photosynthesis are not fully understood. By learning how biology makes fuels using cheap resources (sunlight, water, proteins, abundant metals), molecular-level blueprints can be generated for catalysis strategies with industrial and energy applications. This project aims to reveal the mechanism by which manganese and calcium ions bind to a photosynthetic protein to make an active site where molecular oxygen is released when water is oxidized. Protein samples will be prepared in the PI’s home laboratory and then studied using advanced instrumentation in the Solar Energy Conversion Group at Argonne National Laboratory (ANL). The PI and one graduate student will gain hands-on experience in spectroscopic techniques. Skills learned during this fellowship will advance the development of this type of instrumentation at the home institution to increase research capabilities and provide opportunities for future students.This project aims to reveal the chemical mechanism of the assembly of the Photosystem II oxygen-evolving complex (OEC). This metallic cluster is built in situ from free manganese ions, calcium ions, and water without the use of protein transporters or scaffolds. Advanced electron paramagnetic resonance (EPR) spectroscopy tools available at ANL will be used to characterize protein samples prepared to mimic various stages of OEC assembly. The hosts at ANL will provide facility access, training, technical expertise, and assistance with data analysis. Through this work, new insights into the mechanism of OEC assembly will be produced and a new collaboration between the PI and hosts at ANL will be established. The skills and knowledge in advanced EPR methods gained by the PI will be used to improve the research infrastructure in Louisiana.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.