Nawrocki W J, Bailleul B, Cardol P, Rappaport F, Wollman F-A, Joliot P
Institut de Biologie Physico-Chimique, UMR 7141 CNRS-Sorbonne Université, 13 rue P. et M. Curie, 75005 Paris, France; Laboratoire de Génétique et Physiologie des Microalgues, Institut de Botanique, Université de Liège, 4, Chemin de la Vallée, B-4000 Liège, Belgium.
Institut de Biologie Physico-Chimique, UMR 7141 CNRS-Sorbonne Université, 13 rue P. et M. Curie, 75005 Paris, France.
Biochim Biophys Acta Bioenerg. 2019 May 1;1860(5):425-432. doi: 10.1016/j.bbabio.2019.01.004. Epub 2019 Feb 1.
Cyclic electron flow (CEF) is defined as a return of the reductants from the acceptor side of Photosystem I (PSI) to the pool of its donors via the cytochrome bf. It is described to be complementary to the linear electron flow and essential for photosynthesis. However, despite many efforts aimed to characterize CEF, its pathway and its regulation modes remain equivocal, and its physiological significance is still not clear. Here we use novel spectroscopic to measure the rate of CEF at the onset of light in the green alga Chlamydomonas reinhardtii. The initial redox state of the photosynthetic chain or the oxygen concentration do not modify the initial maximal rate of CEF (60 electrons per second per PSI) but rather strongly influence its duration. Neither the maximal rate nor the duration of CEF are different in the pgrl1 mutant compared to the wild type, disqualifying PGRL1 as the ferredoxin-plastoquinone oxidoreductase involved in the CEF mechanism.
循环电子流（CEF）被定义为还原物从光系统I（PSI）的受体侧通过细胞色素bf回到其供体库的过程。它被认为是线性电子流的补充，对光合作用至关重要。然而，尽管人们为表征CEF付出了诸多努力，但其途径和调节模式仍不明确，其生理意义也尚不清楚。在此，我们使用新颖的光谱学方法来测量莱茵衣藻在光照开始时的CEF速率。光合链的初始氧化还原状态或氧气浓度不会改变CEF的初始最大速率（每个PSI每秒60个电子），而是强烈影响其持续时间。与野生型相比，pgrl1突变体中CEF的最大速率和持续时间均无差异，这排除了PGRL1作为参与CEF机制的铁氧还蛋白-质体醌氧化还原酶的可能性。
