The dynamic structure, function and regulation of Photosystem II in photosynthesis

太阳通过光合作用为地球上几乎所有的生命提供能量。太阳能转换是为数不多的生产清洁能源的可再生方式之一，以满足现代文明日益增长的需求。我们的长期研究目标是双重的;在分子水平上了解光合能量转换的机制，并构建可行的人工光合系统，模仿最关键的步骤。负责光捕获和能量转换的天然光系统是蛋白质的复杂组合，将色素和辅因子结合在一起，以创建生物纳米级太阳能转换器。蛋白质不仅仅是支架：它们通过调节色素的颜色来增加光捕获，通过控制辅因子来促进光化学，并密切参与所有光系统反应。光系统II（PSII）通过利用光能将水分解为我们呼吸的氧气，以及用于以化学形式储存能量的电子和质子来催化地球上最重要的能量反应。我们试图了解PSII的蛋白质组分如何优化光吸收的效率和调节，以及它们如何促进水分解反应。通过实验分离出参与特定反应的蛋白质的各个部分并不容易。我们使用分子动力学计算机模拟来帮助我们“看到”蛋白质。我们的模拟使我们能够跟踪PSII中超过300，000个原子的单独运动和相互作用，并与广泛的实验数据一起使用，以了解PSII如何在分子水平上工作。我们还在开发一种人工光合系统，该系统将一种新的色素结合到一种强大的水溶性铁储存蛋白质细菌铁蛋白中。我们独特的基于蛋白质的系统具有光化学活性，模拟PSII中水裂解反应的第一步，并具有足够高的氧化电位，最终氧化水。我们建议继续开发细菌铁蛋白光系统，最终目标是光驱动水分解并纳入可行的能量储存系统。

The sun powers almost all life on earth via photosynthesis. Solar energy conversion is one of the few renewable ways to produce clean energy to meet the increasing demands of modern civilization. Our long term research objectives are twofold; understand the mechanisms of photosynthetic energy conversion at the molecular level and construct feasible artificial photosynthetic systems mimicking the most crucial steps. The natural photosystems responsible for light capture and energy conversion are complex assemblies of proteins holding pigments and cofactors together to create biological nano-scale solar energy converters. The proteins are more than mere scaffolding: they increase light capture by tuning the colours of the pigments, facilitate photochemistry by controlling the cofactors and are intimately involved in all photosystem reactions. Photosystem II (PSII) catalyses the most energetically important reaction on earth by using light energy to split water into the oxygen we breathe, and electrons and protons used to store energy in chemical form. We seek to understand how the protein components of PSII optimize the efficiency and regulation of light absorption and how they facilitate the water-splitting reaction. It is not easy to experimentally isolate individual parts of the protein involved in specific reactions. We use molecular dynamics computer simulations to help us “see” the protein. Our simulations allow us to follow the individual motions and interactions of over 300,000 atoms in PSII and are used with a wide array of experimental data to understand how PSII works at a molecular level. We are also developing an artificial photosynthetic system that incorporates a novel pigment into a robust water soluble iron storage protein, bacterioferritin. Our unique protein based system is photochemically active, emulates the first steps of the water-splitting reaction in PSII and has a high enough oxidizing potential to ultimately oxidize water. We propose to continue our development of the bacterioferritin photosystem with the ultimate goal of light driven water-splitting and incorporation into a viable energy storage system.