Quantification of superoxide radical production in thylakoid membrane using cyclic hydroxylamines

Kozuleva, Marina; Klenina, I. B.; Mysin, Ivan; Kirilyuk, Igor A.; Opanasenko, V. K.; Proskuryakov, I. I.; Иванов, Б. Н.

doi:10.1016/j.freeradbiomed.2015.08.016

Cited by 28 publications

(10 citation statements)

References 65 publications

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“…Changes in O2 (the stable isotope In preliminary experiments, using the approach described in (20,32), we confirmed that lightdependent O2 consumption resulted from direct ET from PSI cofactors to O2 (Table S2 and Table S3).…”

Section: Measurement Of O2 Concentration Changes Using Mimssupporting

confidence: 57%

The Mehler reaction site is the Phylloquinone within Photosystem I

Kozuleva

Petrova

Milrad

et al. 2020

Preprint

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Photosynthesis is a vital process, responsible for fixing carbon dioxide, and producing most of the organic matter on the planet. However, photosynthesis has some inherent limitations in utilizing solar energy. Up to a third of the energy absorbed is lost in the reduction of O2 to produce the superoxide radical, which occurs principally within photosystem I (PSI) via the Mehler reaction. Strikingly, the precise location as well as the evolutionary role of the reaction have long been a matter of debate. For decades, O2 reduction was assumed to take place solely in the distal iron-sulfur clusters of PSI rather than within the two asymmetrical cofactor branches. Here we demonstrate that under high irradiance, O2 photoreduction by PSI takes place at the phylloquinone of one of the branches (the A-branch). This conclusion derives from the light dependency of the O2 photoreduction rate constant, and from the high rates of O2 photoreduction in PSI complexes lacking iron-sulfur clusters and in a mutant PSI, in which the lifetime of this phyllosemiquinone state is extended 100-fold. On these grounds, we suggest that the Mehler reaction serves as a release valve, functioning only when needed, under conditions where both the distal iron-sulfur clusters of PSI and the mobile ferredoxin pool are over reduced.

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Section: Measurement Of O2 Concentration Changes Using Mimssupporting

confidence: 57%

The Mehler reaction site is the Phylloquinone within Photosystem I

Kozuleva

Petrova

Milrad

et al. 2020

Preprint

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“…The PET chain was reconstituted by addition of Fd and NADP + . Figure 4, A and B, show light-dependent thylakoid O 2 c2 generation using the O 2 c2 detector 1-hydroxy-4-isobutyramido-2,2,6,6-tetramethylpiperidinium, which can react with O 2 c2 in both soluble and membrane phases (Kozuleva et al, 2011;Kozuleva et al, 2015). Addition of SOD to the suspension, eliminating soluble O 2 c2 , allowed dissection of free radical generation by membrane-bound and soluble pathways.…”

Section: C2mentioning

confidence: 99%

Ferredoxin:NADP(H) Oxidoreductase Abundance and Location Influences Redox Poise and Stress Tolerance

Kozuleva

Goss²,

Twachtmann³

et al. 2016

Plant Physiol.

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In linear photosynthetic electron transport, ferredoxin:NADP(H) oxidoreductase (FNR) transfers electrons from ferredoxin (Fd) to NADP Both NADPH and reduced Fd (Fd) are required for reductive assimilation and light/dark activation/deactivation of enzymes. FNR is therefore a hub, connecting photosynthetic electron transport to chloroplast redox metabolism. A correlation between FNR content and tolerance to oxidative stress is well established, although the precise mechanism remains unclear. We investigated the impact of altered FNR content and localization on electron transport and superoxide radical evolution in isolated thylakoids, and probed resulting changes in redox homeostasis, expression of oxidative stress markers, and tolerance to high light in planta. Our data indicate that the ratio of Fd to FNR is critical, with either too much or too little FNR potentially leading to increased superoxide production, and perception of oxidative stress at the level of gene transcription. In FNR overexpressing plants, which show more NADP(H) and glutathione pools, improved tolerance to high-light stress indicates that disturbance of chloroplast redox poise and increased free radical generation may help "prime" the plant and induce protective mechanisms. In fnr1 knock-outs, the NADP(H) and glutathione pools are more oxidized relative to the wild type, and the photoprotective effect is absent despite perception of oxidative stress at the level of gene transcription.

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“…Most of the probes are commercially available or can be prepared from simple commercially available nitroxides (4,15,33,51,70,75,79,87,91,93). Nitroxides are certainly the broadest family of stable free radicals.…”

Section: What Are Hydroxylamine Spin Probes?mentioning

confidence: 99%