Oxidation of the plastoquinone pool in chloroplast thylakoid membranes by superoxide anion radicals
Oxidation of the plastoquinone pool in chloroplast thylakoid membranes by superoxide anion radicals
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DOI：
10.1002/1873-3468.13237
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发表时间：
2018-10-01
期刊：
影响因子：
3.5
通讯作者：
Ivanov, Boris N.
中科院分区：
文献类型：
--
作者：
Borisova-Mubarakshina, Maria M.;Naydov, Ilya A.;Ivanov, Boris N.
叶绿体类囊体膜中的质体醌（PQ）库是光合电子传递链（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重要作用。类囊体膜中的氧还原产生超氧阴离子自由基（O-2（中心点-）），它可能与 PQ 库发生反应。在这里，我们使用分离的类囊体，首次展示了 O-2（中心点-）对 PQ 池的氧化。黄嘌呤-黄嘌呤氧化酶系统用于向类囊体膜外部提供 O-2（中心点-），并通过跟踪叶绿素 a 荧光来监测 PQ 池的氧化还原状态。我们提出，在体内，光系统 I 中产生的 O-2（中心点-）与还原的 PQ（质体氢醌）发生反应，产生过氧化氢，它作为传递 PETC 氧化还原状态信号的信使。
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 (O-2(center dot-)), which may react with the PQ-pool. Here, using isolated thylakoids, we show for the first time the oxidation of the PQ-pool by O-2(center dot-). The xanthine-xanthine oxidase system was used to supply O-2(center dot-) 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 O-2(center dot-) produced in Photosystem I with reduced PQ (plastohydroquinone) creates hydrogen peroxide, which serves as a messenger that signals the redox state of the PETC.