PLASTOQUINONE POOL AND CYTOCHROME b6f ARE INVOLVED IN STATE TRANSITIONS OF Synechocystis sp. PCC 6803
质体醌库和细胞色素b6f参与调控蓝细菌 Synechocystis sp. PCC 6803的状态转换

The effects of 1,4-benzoquinone (BQ) and 2,5-dibromo-3-methy l- 6-isopropyl-p-benzoquinone (DBMIB) on the state transitions of Synechocyst is sp. PCC 6803 were investigated by using modulated chlorophyll fluores cence. Both BQ and DBMIB are benzoquinone analogues and can accept el ectrons from plastoquinone. DBMIB also can bind to the Qo site of th e cytochrome b 6 f complex with high affin-ity. In the absence of actinic light, B Q induced a transition from state 2 to state 1 in dark-adapted cells. To the contrary, DBMIB induced transition to state 2 in the presence of BQ or DCMU (3-(3',4'-dichlorophenyl)-1,1-dimethylurea). These results imply that the redox state of plastoquinone pool con-trols the state transitions and cytochrome b 6 f is involved in these processes.