Flavodiiron proteins 1–to-4 function in versatile combinations in O2 photoreduction in cyanobacteria

eLife

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[1] Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland;

关键词: photosynthesis;    cyanobacteria;    alternative-electron transport;    mehler-like reaction;    flavodiiron protein;    photoprotection;    Other;   

DOI  :  10.7554/eLife.45766

来源: publisher

【 摘 要 】

10.7554/eLife.45766.001Flavodiiron proteins (FDPs) constitute a group of modular enzymes widespread in Bacteria, Archaea and Eukarya. Synechocystis sp. PCC 6803 has four FDPs (Flv1-4), which are essential for the photoprotection of photosynthesis. A direct comparison of light-induced O2 reduction (Mehler-like reaction) under high (3% CO2, HC) and low (air level CO2, LC) inorganic carbon conditions demonstrated that the Flv1/Flv3 heterodimer is solely responsible for an efficient steady-state O2 photoreduction under HC, with flv2 and flv4 expression strongly down-regulated. Conversely, under LC conditions, Flv1/Flv3 acts only as a transient electron sink, due to the competing withdrawal of electrons by the highly induced NDH-1 complex. Further, in vivo evidence is provided indicating that Flv2/Flv4 contributes to the Mehler-like reaction when naturally expressed under LC conditions, or, when artificially overexpressed under HC. The O2 photoreduction driven by Flv2/Flv4 occurs down-stream of PSI in a coordinated manner with Flv1/Flv3 and supports slow and steady-state O2 photoreduction.

【 授权许可】

CC BY