Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia.
FEBS Lett. 2018 Oct;592(19):3221-3228. doi: 10.1002/1873-3468.13237. Epub 2018 Sep 17.
The plastoquinone (PQ)-pool in chloroplast thylakoid membranes is a key electron carrier in the photosynthetic electron transport chain (PETC), and its redox state plays an essential role in the control of plant metabolism. Oxygen reduction in thylakoid membranes produces superoxide anion radicals ( ), which may react with the PQ-pool. Here, using isolated thylakoids, we show for the first time the oxidation of the PQ-pool by . The xanthine-xanthine oxidase system was used to supply externally to the thylakoid membrane and the redox state of the PQ-pool was monitored by tracking chlorophyll a fluorescence. We propose that, in vivo, the reaction of produced in Photosystem I with reduced PQ (plastohydroquinone) creates hydrogen peroxide, which serves as a messenger that signals the redox state of the PETC.
质体醌（PQ）库存在叶绿体类囊体膜中是光合电子传递链（PETC）中的关键电子载体，其氧化还原状态在植物代谢的控制中起着至关重要的作用。类囊体膜中的氧还原会产生超氧阴离子自由基（ ），它可能与 PQ 库发生反应。在这里，我们首次使用分离的类囊体显示了 对 PQ 库的氧化作用。黄嘌呤-黄嘌呤氧化酶系统用于向类囊体膜外部提供 ，并通过跟踪叶绿素 a 荧光来监测 PQ 库的氧化还原状态。我们提出，在体内，与还原型 PQ（质氢醌）反应产生的 会生成过氧化氢，它作为一种信使，信号传递 PETC 的氧化还原状态。
