Chromatic Regulation of Cytochrome Composition and Electron Transfer from Cytochrome b_6-f Complex to Photosystem I in Anacystis nidulans (Tx 20)

概要

論文の詳細を見る
Cytochrome composition of the cyanobacterial photosynthetic system was studied with Anacystis nidulans (Tx 20) in relation to the chromatic regulation of photosystem composition. Comparison of cytochrome compositions in cells with a high PS I/II ratio (3.0, grown under weak orange light) and with a low ratio (1.6, grown under weak red light) indicated that cytochrome composition was also changed in the chromatic regulation of photosystem composition. Two types of cytochrome change were observed: 1) contents of cytochromes c_<553> and c_<548> were changed in parallel with the changes in PS I content, and 2) cytochrome b_<559> and cytochrome b_6-f complex were held at a constant molar ratio to PS II. The molar ratio, PS II : cytochrome b_<559> : cytochrome b_6-f complex : cytochrome c_<553> : PS I : cytochrome c_<548>, in the red-grown cells was 1 : 2.5 : 1.3 : 0.17 : 1.6 : 0.67, and the ratio in the orange-grown cells, 1 : 2.4 : 0.9 : 0.32 : 3.0 : 1.2. In both types of cells, almost all cytochrome f in the cytochrome b_6-f complex was rapidly oxidized after multiple flash activation, indicating that all cytochrome b_6-f complexes in cells of both types are functionally connected to PS I, even when the molar ratio to PS I is largely changed. The content of cytochrome c_<553> was at most 0.14 of PS I, suggesting that the cytochrome turns over several times per one turnover of PS I.
日本植物生理学会の論文