蓝细菌的光合作用系统共结合多达22-23个铁原子，因此对于缺铁胁迫非常敏感，其中最主要的响应就是缺铁诱导蛋白- - IsiA的大量诱导合成。除了被缺铁胁迫诱导并与PS I三聚体形成复合体以外，我们的前期研究发现，IsiA还可以形成IsiA-PS I-PS II超级蛋白复合体并且在蓝细菌Synechocystis PCC 6803光合作用的状态转换中起重要作用。. 到目前为止，虽然国际国内同行对IsiA进行了大量的生理学和功能研究，但是关于IsiA的相互作用蛋白及其相互作用机理，以及IsiA如何实现其生理功能等等重要科学问题，都有待于进一步的深入研究。鉴于以上研究背景和我们已有的工作基础，提出以蓝细菌Synechocystis PCC 6803为材料，构建IsiA-缺失突变体和IsiA-6XHis标签突变体，通过遗传学、蛋白质组学、生理学和生物化学等实验手段，对上述科学问题进行探讨。

Iron deficiency and other stress conditions strongly impact photosynthetic apparatus in photosynthetic organisms. The photosynthetic apparatus of cyanobacteria, containing 22-23 iron atoms, is highly vulnerable to iron deficiency. Iron starvation results in various structural and functional changes within the cyanobacterial cells, among these changes is the appearance of a chlorophyll (Chl)-protein complex associated with the isiA gene product IsiA, or CP43'. The IsiA protein induced by iron starvation is known to encircle the PS I reaction centers, forming a protein supercomplex consisting of a trimeric PS I and a circle of 18 IsiA subunits. While the protein is most strongly induced by iron starvation and becomes the major Chl-binding protein within the cells under this condition, it has been reported to be inducible to some extent (at least transcriptionally) by other environmental stresses, including salt stress, heat stress, oxidative stress, and high or limited light conditions. . In preivious papers, we reported the observation of a novel Chl-containing IsiA supercomplex (IsiA-PS I-PS II supercomplex) in addition to the IsiA-PS I trimer complex by sucrose gradient ultracentrifugation in Synechocystis PCC 6803 under extensive iron starvation, and further results shown that IsiA is critical for efficient state transition.. Beside the physiological and functional ananlysis of IsiA, however, no biochemical analyses of IsiA or its associated protein or protein complexes were performed in these studies, and no evidences show direct interaction between IsiA and PS I or PS II. To find the answers the above scientific questions, in this study, by using Synechocystis PCC 6803 as a model system, we proposed to study the IsiA interacted proteins with the construction of IsiA- and IsiA-6?His mutants, through a series of methodologies include genetics, proteomics, physiology and biochemistry.