The reduction of the oxygen-evolving system in chloroplasts by thylakoid components

Vermaas, Wim F. J.; Ренгер, Г.; Dohnt, Gerhard

doi:10.1016/0005-2728(84)90028-8

Cited by 219 publications

(141 citation statements)

References 21 publications

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“…This indicates that the modulation of F v in TTFs preceded by N STFs occurs with a period-of-four oscillation. The modulation pattern of DF v is in fair agreement with electron transport regulation at the Y z to P 680 + donor side of PSII, if it is assumed that chloroplasts, dark-adapted for tens of minutes, have as an average a S 1 /S 0~0 .75/0.25 heterogeneity (Vermaas et al 1984). Whether or not, and if so to what extent the modulation pattern will change in preparations that have been dark-adapted for several hours remains to be established.…”

Section: Discussionsupporting

confidence: 64%

On the chlorophyll a fluorescence yield in chloroplasts upon excitation with twin turnover flashes (TTF) and high frequency flash trains

2007

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Chlorophyll fluorescence is routinely taken as a quantifiable measure of the redox state of the primary quinone acceptor Q A of PSII. The variable fluorescence in thylakoids increases in a single turnover flash (STF) from its low dark level F o towards a maximum F m STF when Q A becomes reduced. We found, using twin single turnover flashes (TTFs) that the fluorescence increase induced by the first twin-partner is followed by a 20-30% increase when the second partner is applied within 20-100 ls after the first one. The amplitude of the twin response shows a period-of-four oscillation associated with the 4-step oxidation of water in the Kok cycle (S states) and originates from two different trapped states with a life time of 0.2-0.4 and 2-5 ms, respectively. The oscillation is supplemented with a binary oscillation associated with the two-electron gate mechanism at the PSII acceptor side. The F(t) response in high frequency flash trains (1-4 kHz) shows (i) in the first 3-4 flashes a transient overshoot 20-30% above the F m STF = 3*F o level reached in the 1st flash with a partial decline towards a dip D in the next 2-3 ms, independent of the flash frequency, and (ii) a frequency independent rise to F m = 5*F o in the 3-60 ms time range. The initial overshoot is interpreted to be due to electron trapping in the S 0 fraction with Q B -nonreducing centers and the dip to the subsequent recovery accompanying the reoxidation of the double reduced acceptor pair in these RCs after trapping. The rise after the overshoot is, in agreement with earlier findings, interpreted to indicate a photo-electrochemical control of the chlorophyll fluorescence yield of PSII. It is anticipated that the double exciton and electron trapping property of PSII is advantageous for the plant. It serves to alleviate the depression of electron transport in single reduced Q B -nonreducing RCs, associated with electrochemically coupled proton transport, by an increased electron trapping efficiency in these centers.Keywords Chlorophyll a Á Fluorescence quenching Á Q B -nonreducing center Á Single turnover excitation Á Twin turnover excitation Á Three state trapping mechanism (TSTM)

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Section: Discussionsupporting

confidence: 64%

On the chlorophyll a fluorescence yield in chloroplasts upon excitation with twin turnover flashes (TTF) and high frequency flash trains

2007

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“…[37][38][39][40] Because these dark recombination reactions happen in seconds, the interval between the Xe lamp or Nd:YAG laser flashes (~1. …”

Section: Synchronization Of the S State Formationmentioning

confidence: 99%

Structural Change of the Mn Cluster during the S₂→S₃ State Transition of the Oxygen-Evolving Complex of Photosystem II. Does It Reflect the Onset of Water/Substrate Oxidation? Determination by Mn X-ray Absorption Spectroscopy

et al. 2000

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The oxygen-evolving complex of Photosystem II in plants and cyanobacteria catalyzes the oxidation of two water molecules to one molecule of dioxygen. A tetranuclear Mn complex is believed to cycle through five intermediate states (S 0 -S 4 ) to couple the four-electron oxidation of water with the one-electron photochemistry occurring at the Photosystem II reaction center. We have used X-ray absorption spectroscopy to study the local structure of the Mn complex and have proposed a model for it, based on studies of the Mn K-edges and the extended X-ray absorption fine structure of the S 1 and S 2 states. The proposed model consists of two di-μ-oxo-bridged binuclear Mn units with Mn-Mn distances of ~2.7 Å that are linked to each other by a mono-μ-oxo bridge with a Mn-Mn separation of ~3.3 Å. The Mn-Mn distances are invariant in the native S 1 and S 2 states. This report describes the application of X-ray absorption spectroscopy to S 3 samples created under physiological conditions with saturating flash illumination. Significant changes are observed in the Mn-Mn distances in the S 3 state compared to the S 1 and the S 2 states. The two 2.7 Å Mn-Mn distances that characterize the di-μ-oxo centers in the S 1 and S 2 states are lengthened to ~2.8 and 3.0 Å in the S 3 state, respectively. The 3.3 Å Mn-Mn and Mn-Ca distances also increase by 0.04-0.2 Å. These changes in Mn-Mn distances are interpreted as consequences of the onset of substrate/water oxidation in the S 3 state. Mn-centered oxidation is evident during the S 0 →S 1 and S 1 →S 2 transitions. We propose that the changes in Mn-Mn distances during the S 2 →S 3 transition are the result of ligand or water oxidation, leading to the Supporting Information Available: E-space S 3 state EXAFS spectrum; the data in k-space and the background that was removed to reduce the low-frequency contributions that show up as peaks at <1 Å in the Fourier transform; and the Fourier isolate of the k-space S 3 spectrum, shown overplotted on the S 3 EXAFS spectrum (PDF). This material is available free of charge via the Internet at http:// pubs.acs.org. NIH Public Access

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“…It is well known that the intermediary redox states referred to as Si states [6] exhibit characteristic kinetics and thermodynamic properties but the electronic configuration and nuclear geometry of these states are unknown. Surprisingly, in dark-adapted samples, the redox state Si is practically exclusively populated [7]. SZ and Sj decay in the range of seconds up to a few minutes by electron transfer either from the reduced form of component Yn, identified as Tyr-160 of polypeptide D2 in Synechocystis sp.…”

Section: Introductionmentioning

confidence: 97%

The reactivity of hydrazine with photosystem II strongly depends on the redox state of the water oxidizing system

Messinger

Ренгер

1990

FEBS Letters

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The decay kinetics of the redox states SZ and & of the water-oxidizing enzyme have been analyzed in isolated spinach thylakoids in the absence and presence of the exogenous reductant hydrazine. In control samples without NHrNHr a biphasic decay is observed. The rapid decline of 5% and S, with Yo as reductant exhibits practically the same kinetics with rm=67 s at pH=7.2 and 7°C. The slow reduction (order of 5-10 min at 7C) of S2 and S, with endogenous electron donors other than Yn is about twice as fast for S2 as for S, under these conditions. In contrast, the hydrazine-induced reductive shifts of the formal redox states S, (i = 0 3) are characterized by a totally different kinetic pattern: (a) at 1 mM NH2NH2 and incubation on ice the decay of S2 is estimated to be at least 25 times faster (t,,,<0.4 min) than the corresponding reaction of Sj E::;: E 13 min); (b) the NH?NHr-induced decay of S, is even slower (about twice) than the transformation of S, into the forma1 redox state 'S_,' ~6 min), which gives rise to the two-digit phase shift of the oxygen-yield pattern induced by a flash train in dark adapted thylakoids. (c) the NH2NH2-induced transformation So -+X2' [Renger, Messinger and Hanssum (1990) in: Curr. Res. Photosynth. (Baltscheffsky, M., ed), Vol. 1, pp. 845-848, Kluwer, Dordrecht] is about three times faster (t,,2~2 min) than the reaction S, % 'S,'. Based on these results, the following dependence on the redox state S, of the reactivity towards NHzNHz is obtained: SA < S, < So 4 Sr. The implications of this surprising order of reactivity are discussed.

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The reduction of the oxygen-evolving system in chloroplasts by thylakoid components

Cited by 219 publications

References 21 publications

On the chlorophyll a fluorescence yield in chloroplasts upon excitation with twin turnover flashes (TTF) and high frequency flash trains

On the chlorophyll a fluorescence yield in chloroplasts upon excitation with twin turnover flashes (TTF) and high frequency flash trains

Structural Change of the Mn Cluster during the S₂→S₃ State Transition of the Oxygen-Evolving Complex of Photosystem II. Does It Reflect the Onset of Water/Substrate Oxidation? Determination by Mn X-ray Absorption Spectroscopy

The reactivity of hydrazine with photosystem II strongly depends on the redox state of the water oxidizing system

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The reduction of the oxygen-evolving system in chloroplasts by thylakoid components

Cited by 219 publications

References 21 publications

On the chlorophyll a fluorescence yield in chloroplasts upon excitation with twin turnover flashes (TTF) and high frequency flash trains

On the chlorophyll a fluorescence yield in chloroplasts upon excitation with twin turnover flashes (TTF) and high frequency flash trains

Structural Change of the Mn Cluster during the S2→S3 State Transition of the Oxygen-Evolving Complex of Photosystem II. Does It Reflect the Onset of Water/Substrate Oxidation? Determination by Mn X-ray Absorption Spectroscopy

The reactivity of hydrazine with photosystem II strongly depends on the redox state of the water oxidizing system

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Structural Change of the Mn Cluster during the S₂→S₃ State Transition of the Oxygen-Evolving Complex of Photosystem II. Does It Reflect the Onset of Water/Substrate Oxidation? Determination by Mn X-ray Absorption Spectroscopy