Rochaix J, Fischer N, Hippler M
Departments of Molecular Biology and Plant Biology, University of Geneva, 30, quai Ernest-Ansermet, 1211 4, Geneva, Switzerland.
Biochimie. 2000 Jun-Jul;82(6-7):635-45. doi: 10.1016/s0300-9084(00)00604-0.
The photosystem I (PSI) complex is a multisubunit protein-pigment complex embedded in the thylakoid membrane which acts as a light-driven plastocyanin/cytochrome c(6)-ferredoxin oxido-reductase. The use of chloroplast transformation and site-directed mutagenesis coupled with the biochemical and biophysical analysis of mutants of the green alga Chlamydomonas reinhardtii with specific amino acid changes in several subunits of PSI has provided new insights into the structure-function relationship of this important photosynthetic complex. In particular, this molecular-genetic analysis has identified key residues of the reaction center polypeptides of PSI which are the ligands of some of the redox cofactors and it has also provided important insights into the orientation of the terminal electron acceptors of this complex. Finally this analysis has also shown that mutations affecting the donor side of PSI are limiting for overall electron transfer under high light and that electron trapping within the terminal electron acceptors of PSI is highly deleterious to the cells.
光系统I（PSI）复合体是一种嵌入类囊体膜的多亚基蛋白质-色素复合体，作为光驱动的质体蓝素/细胞色素c6-铁氧化还原蛋白氧化还原酶发挥作用。利用叶绿体转化和定点诱变，结合对莱茵衣藻绿藻PSI几个亚基具有特定氨基酸变化的突变体进行生化和生物物理分析，为这个重要光合复合体的结构-功能关系提供了新见解。特别是，这种分子遗传学分析确定了PSI反应中心多肽的关键残基，这些残基是一些氧化还原辅因子的配体，并且还为该复合体末端电子受体的方向提供了重要见解。最后，该分析还表明，影响PSI供体侧的突变在高光下限制了整体电子转移，并且PSI末端电子受体中的电子捕获对细胞具有高度有害性。
