Control of electron transport routes through redox-regulated redistribution of respiratory complexes

作者：Lu‐Ning Liu, Samantha J. Bryan, Fang Huang, Jianfeng Yu, Peter J. Nixon, Peter R. Rich, Conrad W. Mullineaux · 发表于：Proceedings of the National Academy of Sciences · 年份：2012 · DOI：10.1073/pnas.1120960109 · 被引用次数：108 · 研究领域：Photosynthetic Processes and Mechanisms、Photoreceptor and optogenetics research、Mitochondrial Function and Pathology

In cyanobacteria, respiratory electron transport takes place in close proximity to photosynthetic electron transport, because the complexes required for both processes are located within the thylakoid membranes. The balance of electron transport routes is crucial for cell physiology, yet the factors that control the predominance of particular pathways are poorly understood. Here we use a combination of tagging with green fluorescent protein and confocal fluorescence microscopy in live cells of the cyanobacterium Synechococcus elongatus PCC 7942 to investigate the distribution on submicron scales of two key respiratory electron donors, type-I NAD(P)H dehydrogenase (NDH-1) and succinate dehydrogenase (SDH). When cells are grown under low light, both complexes are concentrated in discrete patches in the thylakoid membranes, about 100-300 nm in diameter and containing tens to hundreds of complexes. Exposure to moderate light leads to redistribution of both NDH-1 and SDH such that they become evenly distributed within the thylakoid membranes. The effects of electron transport inhibitors indicate that redistribution of respiratory complexes is triggered by changes in the redox state of an electron carrier close to plastoquinone. Redistribution does not depend on de novo protein synthesis, and it is accompanied by a major increase in the probability that respiratory electrons are transferred to photosystem I rather than to a terminal oxidase. These results indicate that the distribu...