On the mechanism of ADRY agent interaction with the Photosystem II donor side

Hanssum, B.; Dohnt, Gerhard; Ренгер, Г.

doi:10.1016/0005-2728(85)90098-2

Cited by 64 publications

(38 citation statements)

References 17 publications

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“…as A D R Y type reagents [14,15]. Among the great variety of com pounds the effects of 1,4-benzoquinone derivatives are of special interest because of their similarities with the natural plastoquinones.…”

Section: Introductionmentioning

confidence: 99%

Tribromotoluquinone Induced Modifications of the Oscillation Pattern of Oxygen Evolution and of Herbicide Binding in Thylakoids and PS II Membrane Fragments from Spinach

Ренгер

Messinger

Fromme

1989

Zeitschrift Für Naturforschung C

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M ax-V olm er-Institut für B iophysikalische und Physikalische C hem ie, T U B erlin. S traße des 17. Ju n i 135. 1000 B erlin 12 Z. N aturforsch. 44c, 423-430 (1989); received Ja n u a ry 2 6/F ebruary 23, 1989 Dedicated to Professor A chim Trebst on the occasion o f his 60th birthday Photosystem II, H a lo g en ated /?-B enzoquinones, O xygen Y ield O scillation, Q u in o n e /H erb icid e In tera ctio n , B inding SitesIn the p re sen t study the effect o f T B T Q on PS II and its m utual interaction with D C M U was analyzed by m easu rem en ts o f th e oxygen yield oscillation p a tte rn and o f D C M U binding. It was found: 1 )T B T Q in its reduced form is able to induce the red u ctio n o f D ox which gives rise to an accelerated decay of S2 and S3 o f the w ateroxidizing com plex. 2 ) T rito n X-100 trea tm e n t used for isolation o f PS II m em b ran e fragm ents does not significantly affect the lateral m obility o f p lasto q u in o n e w ithin the m em b ran e. T B T Q bound to the th y lakoid m em b ran e does not en h an c e the e lectro n pool capacity in PS II m em b ran e fragm ents. [7]) of the PS II reaction center and even the catalytic site of water oxidation (for reviews, see ref. [8 , 9]). Despite the huge pro gress in our understanding of the structural organiza tion of system II during the last years [8 , 9] the possi-

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Section: Introductionmentioning

confidence: 99%

Tribromotoluquinone Induced Modifications of the Oscillation Pattern of Oxygen Evolution and of Herbicide Binding in Thylakoids and PS II Membrane Fragments from Spinach

Ренгер

Messinger

Fromme

1989

Zeitschrift Für Naturforschung C

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“…In the concentration range affecting the Q and B bands, acridone even enhanced the intensity of the bands at -20°C and +50°C (Fig. 6) (22,24,25). The bands at -20°C and +50°C originate from the charge recombination of tyrosine(Yz) or histidine(His+)QA and tyrosine (Y)QA, respectively, as lower S states are enhanced (26,27).…”

Section: Resultsmentioning

confidence: 99%

Acridones: a chemically new group of protonophores.

Horváth¹,

Droppa²,

Fodorpataki³

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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Although the interaction of proton-conducting ionophores (protonophores) with photosynthetic electron transport has been extensively studied during the past decade, the mode of action of protonophores remained uncertain. For a better understanding of the molecular mechanism of the action of protonophores, the introduction of chemically new types of molecules will be required. In this work, we demonstrate that acridones (9-azaanthracene-10-ones) completely fulfill this requirement. At low concentrations of acridones, the thermoluminescence bands at +20°C and +10°C were strongly inhibited, while normal electron transport activity was retained. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.In this study we present evidence that acridones (9-azaanthracene-10-ones) (6) operate as typical protonophores, accelerating the decay of the electrochromic absorbance transient and inhibiting the buildup of the transmembrane ApH. It is also shown that these agents uncouple photophosphorylation and act as an ADRY reagent (accelerators of deactivation reactions of the water-splitting enzyme, Y). Acridones also facilitate the oxidation of the high potential form of cytochrome b559 and its conversion into intermediary-or lowpotential forms. MATERIALS AND METHODSPeas (Pisum sativum cv. Rajnai torpe) were grown under standard greenhouse conditions, and leaves were freshly harvested before each experiment. Intact chloroplasts were isolated essentially as described by Thorne et al. (7), and the chlorophyll content of the samples was estimated as described by Arnon (8).The rate of photosynthetic oxygen evolution and uptake was measured as described by Droppa et al. (9) by using a Clarktype 02 electrode (Rank Brothers, Cambridge, U.K.). Different parts of the electron transport chain were studied by the addition of various electron donors and acceptors: 2 mM NaN3 and either 2 mM K3[Fe(CN)6] or 0.1 mM methyl viologen were used to assay the whole electron-transport chain. Photosystem I (PSI) or PSII electron transport was measured by using 0.25 mM p-benzoquinone or 2,5-dichloro-p-benzoquinone, 40 tLM dichlorophenolindophenol, and 2 mM ascorbate, depending on which system was being studied. In specific instances, PSII activity was also measured spectrophotometrically following the photoreduction of dichlorophenolindophenol at 590 nm in the presence and absence of 0.5 mM sym-diphenylcarbazide.Thermoluminescence was measured in the temperature interval from -80 to +80°C with an apparatus similar to that described by Vass et al. (10). Samples were illuminated with white light of 10 W.m-2 for 2 min during continuous cooling from +20 to -80°C and then heated at a constant rate of 20°C/min to measure glow curves. Chemicals were added before the illumination started (11).Fluorescence induction was measured by using a chlorophyll fluorimeter (Biotechnika RT, Szeged, Hungary). Sa...

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“…ADRY agents were thought to act as mobile catalysts [11,12], reducing the Mn cluster in the $2 and $3 states [12,13]. In Tris-washed chloroplasts that are deprived of O2-evolving activity, ADRY agents accelerate the re-reduction of component Yz, Tyr-161 of the photosystem IID 1 polypeptide [14,15].…”

Section: Introductionmentioning

confidence: 99%