Quinones in the Photosynthetic Reaction Center of Green Sulfur Bacteria

绿硫细菌光合反应中心的醌类化合物

基本信息

批准号：
15570135
负责人：
OH-OKA Hirozo
金额：
$ 2.37万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15570135/
关键词：
Green Sulfur Bacteria Photochemical Reaction Center Electron Transfer Energy Transfer NADP^+ Photoredution Cytochrome c bc complex P840 チトクロムc_z チトクロムc-554 チオ硫酸酸化経路イオウ代謝反応中心

项目摘要

Analyses with molecular genetic methods are essential for the study of the electron transfer mechanisms in the photosynthetic reaction center (RC) of green sulfur bacteria on the molecular level. We have therefore made a project concerning a mutant generation with the homologous recombination method which was established in 2001. 1. Analysis of the function of PscD subunit : In order to clarify the unknown function of PscD subunit, which is one of 5 different subunits constituting the RC complex, the mutant lacking PscD subunit was generated by the insertional inactivation of the relevant gene pscD. Although the mutant could grow photosynthetically, the energy transfer from FMO protein to P840 was less efficient compared to the wild type. Activity of NADP^+ photoreduction also declined slightly to about 80%. 2. Analysis of the function of cytochrome c-554 : We performed the flash-excitation experiments using membranes purified from the mutant lacking cytochrome c-554. It was demonstrated that cytochrome cz mediated directly the electron transfer from be complex to P840. Furthermore, cytochrome c-554 could not also accept electrons from bc complex. Two different electron transfer pathways to P840 seems to be functional, that is, one is from bc complex and the other from cytochrome c-554 which is linked with a sulfur oxidation pathway. In the near future, this project will be developed to explore quinones which is supposed to exist within the Chlorobium RC and heliobacterial RC as well.

用分子遗传学方法进行的分析对于研究分子水平上绿硫细菌的光合作用反应中心（RC）中的电子转移机制至关重要。 We have therefore made a project concerning a mutant generation with the homologous recombination method which was established in 2001. 1. Analysis of the function of PscD subunit : In order to clarify the unknown function of PscD subunit, which is one of 5 different subunits constituting the RC complex, the mutant lacking PscD subunit was generated by the insertional inactivation of the relevant gene pscD.尽管突变体可以光合生长，但与野生型相比，从FMO蛋白到p840的能量转移效率较低。 NADP^+光递归的活性也略有下降到约80％。 2。分析细胞色素C-554的功能：我们使用缺乏细胞色素c-554的突变体纯化的膜进行了闪存实验。已证明细胞色素CZ直接介导了电子从Be Complect到P840的转移。此外，细胞色素C-554也无法接受BC复合体的电子。到P840的两个不同的电子转移途径似乎是功能性的，也就是说，一个来自BC复合物，另一个来自与硫氧化途径相关的细胞色素C-554。在不久的将来，将开发该项目来探索奎因酮，这些奎因酮也应该存在于叶绿体RC和Heliobacterial RC中。