Function and Assembly of the Accessory Subunits of Photosystem I

光系统I （PS I）是一种依赖光的质体青素-铁氧化还蛋白氧化还原酶，是叶绿体和蓝藻类囊体膜上的一种光合作用多亚基色素蛋白复合物。PS I中的所有辅因子和电子转移中心都与三个多肽相关；(2)研究这些辅助亚基组装成PS I复合物的要求和机制。要实现第一个目标，最可行的方法是对天然可转化蓝藻聚胞菌PCC 6803中编码这些多肽的基因进行分子克隆和鉴定，然后通过靶向诱变产生特异性缺乏这些基因的突变体。将对这些突变体的PS I进行生化和光谱分析，以评估单个附属多肽的损失对PS I的组装和功能的影响。体外重构系统将用于确定这些多肽组装成PS I的生理需求，并确定其组装顺序。​植物、绿藻和蓝藻通过光合作用的过程，随着分子氧的进化，将光能转化为化学能。含氧光合作用是地球上生物能源和氧气的主要来源，更好地了解这一过程对于面对未来的食物和环境挑战至关重要。

Photosystem I (PS I), the light-dependent plastocyanin- ferredoxin oxidoreductase, is a photosynthetic multisubunit pigment-protein complex in the thylakoid membranes of chloroplasts and cyanobacteria. All cofactors and electron transfer centers in PS I are associated with three polypeptides; the role of the accessory polypeptides, (2) study of the requirements and mechanism of assembly of these accessory subunits into PS I complex. The most feasible approach to achieve the first objective involves molecular cloning and characterization of the genes encoding these polypeptides in the naturally transformable cyanobacterium Synechocystis sp. PCC 6803 and then generating mutants specifically lacking these genes by targeted mutagenesis. Biochemical and spectroscopic analyses of PS I from these mutants will be conducted to assess the effects of loss of individual accessory polypeptides on the assembly and function of PS I. In vitro reconstitution systems will be used to identify the physiological requirements for the assembly of these polypeptides into PS I and to determine the sequence of their assembly. %%% Plants, green algae and cyanobacteria convert light energy into chemical energy with the evolution of molecular oxygen by the process of photosynthesis. Oxygenic photosynthesis is the major source of biological energy and oxygen on this planet and a better understanding of this process is essential for facing the food and environmental challenges of the future.