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。太阳能转换是生产清洁能源以满足现代文明日益增长的需求的为数不多的可再生方法之一。我们的长期研究目标有两个：在分子水平上了解光合作用能量转换的机制，并模拟最关键的步骤构建可行的人工光合作用系统。负责光捕获和能量转换的自然光系统是将色素和辅因子结合在一起的蛋白质的复杂集合，从而创造出生物纳米级太阳能转换器。这些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，并密切参与所有的光系统反应。光系统II(PSII)催化地球上最重要的能量反应，它利用光能将水分解成我们呼吸的氧气，并利用电子和质子以化学形式储存能量。我们试图了解PSII的蛋白质成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。要在实验中分离出参与特定反应的蛋白质的个别部分并不容易。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300,000多个原子的单独运动和相互作用，并与大量实验数据一起使用，以了解PSII在分子水平上的工作原理。我们还在开发一种人工光合作用系统，将一种新的色素结合到一种强大的水溶性铁储存蛋白-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中水分解反应的第一步，并具有足够高的氧化潜力，最终氧化水。我们建议继续我们的细菌铁蛋白光系统的开发，最终目标是光驱动的水分解并并入一个可行的能量存储系统。

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.