Changes in the transthylakoid proton gradient are caused by the movement of phycobilisomes in the cyanobacterium Synechocystis sp. strain PCC 6803  

作　　者：MA WeiMin GAO FuDan MI HuaLing SHEN YunGang 

机构地区：[1]College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China [2]Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China

出　　处：《Chinese Science Bulletin》2011年第3期285-289,共5页

基　　金：supported by the National Natural Science Foundation of China (30770175);the National Basic Research Program of China (2009CB118500);the Key Project of the Chinese Ministry of Education (209045);the Shanghai Leading Academic Discipline Project (S30406);the Leading Academic Discipline Project of Shanghai Normal University (DZL808)

摘　　要：Phycobilisomes (PBSs) are the main accessory light-harvesting complexes in cyanobacteria and their movement between photosystems (PSs) affects cyclic and respiratory electron transport.However,it remains unclear whether the movement of PBSs between PSs also affects the transthylakoid proton gradient (ΔpH).We investigated the effect of PBS movement on ΔpH levels in a unicellular cyanobacterium Synechocystis sp.strain PCC 6803,using glycinebetaine to immobilize and couple PBSs to photosystem II (PSII) or photosystem I (PSI) by applying under far-red or green light,respectively.The immobilization of PBSs at PSII inhibited decreases in ΔpH,as reflected by the slow phase of millisecond-delayed light emission (ms-DLE) that occurs during the movement of PBSs from PSII to PSI.By contrast,the immobilization of PBSs at PSI inhibited the increase in ΔpH that occurs when PBSs move from PSI to PSII.Comparison of the changes in ΔpH and electron transport caused by the movement of PBSs between PSs indicated that the changes in ΔpH were most likely caused by respiratory electron transport.This will further improve our understanding of the physiological role of PBS movement in cyanobacteria.Phycobilisomes （PBSs） are the main accessory light-harvesting complexes in cyanobacteria and their movement between photo- systems （PSs） affects cyclic and respiratory electron transport. However, it remains unclear whether the movement of PBSs between PSs also affects the transthylakoid proton gradient （△pH）. We investigated the effect of PBS movement on ApH levels in a unicellular cyanobacterium Synechocystis sp. strain PCC 6803, using glycinebetaine to immobilize and couple PBSs to photosys- tem II （PSII） or photosystem I （PSI） by applying under far-red or green light, respectively. The immobilization of PBSs at PSII inhibited decreases in △pH, as reflected by the slow phase of millisecond-delayed light emission （ms-DLE） that occurs during the movement of PBSs from PSII to PSI. By contrast, the immobilization of PBSs at PSI inhibited the increase in ApH that occurs when PBSs move from PSI to PSII. Comparison of the changes in ApH and electron transport caused by the movement of PBSs between PSs indicated that the changes in △pH were most likely caused by respiratory electron transport. This will further improve our understanding of the physiological role of PBS movement in cyanobacteria.

关 键 词：质子梯度 藻胆体 运动 蓝藻 跨膜 用户交换机 电子传递 捕光复合体 

分 类 号：Q559[生物学—生物化学] Q949.2