光系统I及相关膜蛋白复合物的结构、组装及动态调控

放氧光合作用产生有机物，释放氧气，为地球上绝大多数生物提供物质能量基础。光合作用的光反应是由光合膜上几个超大的多亚基膜蛋白复合物共同完成的，其中一个重要的复合物就是光系统I（PSI）。光合作用的活性及程度与外界环境密切相关，为了适应自然环境，光合生物中有复杂的调控机制，在不同环境压力或胁迫条件下，光合生物中会诱导表达某些蛋白，或对已有蛋白进行修饰，这些新合成或修饰的蛋白可以与PSI相互作用，形成多种新型的光合膜蛋白复合物。本课题组一直针对光合作用膜蛋白复合物开展结构功能研究，在前期工作基础上，我们拟以光合膜上围绕PSI形成的新型复合物为研究对象，通过结构生物学及其它生化技术手段，揭示这些光合膜蛋白复合物的整体结构及组装方式，蛋白间的相互作用及色素分子的排布规律，阐释复合物的形成与其功能调节间的关系，为深刻理解光合作用机理及调控机制提供结构基础，为相关应用研究提供科学依据。

Oxygenic photosynthetic organisms use solar energy to produce carbohydrates and release oxygen, providing food and energy for almost all living organisms on the planet. The light reactions of photosynthesis are accomplished by several multi-subunit protein complexes embedded in the thylakoid membranes, including photosystem I (PSI). The level and activity of photosynthesis are closely related to the external conditions. In response to the ever-changing natural environment, oxygenic photosynthetic organisms have evolved various adaptive mechanisms to optimize their photosynthetic efficiency and to avoid photo-damage. Under different environmental or stressed conditions, new proteins are induced and expressed, and some proteins are specifically modified in many photosynthetic organisms. These newly synthesized or modified proteins can assembly with PSI to form new kinds of supra-molecular complexes within the thylakoid membranes. Our research group has been focusing on the structural and functional analyses of photosynthetic membrane protein complexes. On the basis of previous works, this research project targets new kinds of PSI and PSI-related supercomplexes embedded in the photosynthetic membranes. This study is expected to solve high resolution structures of these membrane protein complexes. By combining the structural information with biochemical and spectroscopic data, we will be able to elucidate the overall architecture and the assembly mechanism of these photosynthetic complexes, reveal the detailed and specific interactions between protein subunits, and the relationship between the complex formation and their functional regulation. Our results will provide important structural basis for deeper understanding of the molecular mechanism and regulative processes of photosynthesis, and to provide new idea for applied research development.