Determination of the Functioning Site of Chlorophyll a' in the Photosynthetic Reaction Center I

光合反应中心I叶绿素a功能位点的测定

• 批准号: 12450343
• 负责人: WATANABE Tadashi
• 金额: $ 9.41万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450343/
• 关键词: photosynthesis; chlorophyll; reaction center; HPLC; spectrophotometry; supramolecule; protein; complex; 光化学系I; クロロフィルa'; 色素; 二次電子受容体; キノン; クロロフィルa′

The present research has been conducted to draw a conclusion as to the actual number and the in vito functioning site of chloro-phyll a' (Chl a') which the researchers had detected in the vicinity of the reaction center P700 of photosystem I for a variety of oxygenic photo-synthetic organisms. After establishing HPLC conditions by which most of the chlorophylls, carotenoids/ xanthophylls and quinines can be determined in a relatively short time, we analyzed the pigment compositions of higher plants, a thermophilic cyanobacterium, regular cyanbacteria and green alga, the stoichiometry Chl a' /P700 = 1 was concluded.This, together with an X-ray crystallographic result on the system I reaction center of the thermophilic cyanobacterium, reported in 2001 by Jordan et al., finally has led to a conclusion that Chl a' is an essential component of P700 itself, forming a heterodimer with the normal Chl a molecule.In addition to these, the reaction center molecular assemblies of a green sulfur bacterium and of a marine prokaryote have been elucidated for the first time.

本研究旨在得出研究人员在多种含氧光合生物的光系统 I 反应中心 P700 附近检测到的叶绿素 a' (Chl a') 的实际数量和体外功能位点的结论。在建立了可以在相对较短的时间内测定大多数叶绿素、类胡萝卜素/叶黄素和奎宁的 HPLC 条件后，我们分析了高等植物、嗜热蓝藻、普通蓝藻和绿藻的色素成分，得出化学计量 Chl a' /P700 = 1。 Jordan等人于2001年报道的嗜热蓝藻的系统I反应中心，最终得出结论：Chl a'是P700本身的重要组成部分，与正常的Chl a分子形成异二聚体。此外，还首次阐明了绿硫细菌和海洋原核生物的反应中心分子组装体。