Structural Analysis of the Water: Plastoquinone Oxidoreductase from Spinach Thylakoids

Irrgang, Klaus−Dieter; Lekauskas, A.; Franke, P.; Reifarth, F.; Smolian, H.; Karge, M.; Ренгер, Г.

doi:10.1007/978-94-011-3953-3_231

Cited by 5 publications

(8 citation statements)

References 14 publications

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“…Oxygen-evolving PS II core complexes were obtained from spinach PS II membrane fragments by a modified method described previously ( , ) in the presence of β-DM and further centrifugation on sucrose gradients. Samples were stored at 77 K in a buffer containing 25 mM MES (pH 6.5), 35% (w/v) sucrose, 10 mM CaCl 2 , and 0.025% (w/v) β-DM.…”

Section: Methodsmentioning

confidence: 99%

“…Samples were stored at 77 K in a buffer containing 25 mM MES (pH 6.5), 35% (w/v) sucrose, 10 mM CaCl 2 , and 0.025% (w/v) β-DM. These PS II core complexes are mainly monomeric and deprived of the extrinsic 23 and 17 kDa proteins ( , ). Potentiometric titration of Cyt b 559 and spectral measurements on PS II core complexes were performed at 16 °C in an assay medium containing 100 mM buffer (MES, HEPES, Tricine, or CHES, depending on the pH), 10 mM CaCl 2 , 10 mM NaCl, 0.025% (w/v) β-DM, and 10% (v/v) glycerol.…”

Section: Methodsmentioning

confidence: 99%

“…In these samples, neither HP nor IP forms are detected; the Cyt b 559 attains predominantly the LP form (>80% of the total content) (Figure B) with a pH-independent E m of about 120 mV (Figure B). These PS II core complexes are deprived of the extrinsic 17 kDa (PsbQ) and 23 kDa proteins (PsbP) and of the vast majority of lipids ( , ). They exist to a large extent as monomers ( , ), each containing about 50 molecules of bound β-DM ().…”

Section: (1) Redox Propertiesmentioning

confidence: 99%

“…These PS II core complexes are deprived of the extrinsic 17 kDa (PsbQ) and 23 kDa proteins (PsbP) and of the vast majority of lipids ( , ). They exist to a large extent as monomers ( , ), each containing about 50 molecules of bound β-DM (). When the redox properties of Cyt b 559 in this sample type are considered, two parameters are of interest: the E m value and its pH independence.…”

Section: (1) Redox Propertiesmentioning

confidence: 99%

“…A more complicated problem is the lack of any HP and/or IP Cyt b 559 . The E m of Cyt b 559 depends on different parameters (see ref 7 for a review), and therefore, the transformation into the LP form is most likely a combined effect caused by the loss of the 17 and 23 kDa proteins () and the drastic reduction of the lipid content ( , ). An essential determinant of the midpoint potential of cytochromes in general is the encapsulation of the heme group into the protein as illustrated by several studies (see ref 86 and references therein).…”

Section: (1) Redox Propertiesmentioning

confidence: 99%

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Redox and Spectral Properties of Cytochromeb₅₅₉in Different Preparations of Photosystem II

et al. 1999

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A detailed analysis of the properties of cytochrome b(559) (Cyt b(559)) in photosystem II (PS II) preparations with different degrees of structural complexity is presented. It reveals that (i) D1-D2-Cyt b(559) complexes either in solubilized form or incorporated into liposomes contain only one type of Cyt b(559) with E(m) values of 60 +/- 5 and 100 +/- 10 mV, respectively, at pH 6.8; (ii) in oxygen-evolving solubilized PS II core complexes Cyt b(559) exists predominantly (>85%) as an LP form with an E(m,7) of 125 +/- 10 mV and a minor fraction with an E(m,7) of -150 +/- 15 mV; (iii) in oxygen-evolving PS II membrane fragments three different redox forms are discernible with E(m) values of 390 +/- 15 mV (HP form), 230 +/- 20 mV (IP form), and 105 +/- 25 mV (LP form) and relative amplitudes of 58, 24, and 18%, respectively, at pH 7.3; (iv) the E(m) values are almost pH-independent between pH 6 and 9.5 in all sample types except D1-D2-Cyt b(559) complexes incorporated into liposomes with a slope of -29 mV/pH unit, when the pH increases from 6 to 9.5 (IP and LP form in PS II membrane fragments possibly within a restricted range from pH 6.5 to 8); (v) at pH >8 the HP Cyt b(559) progressively converts to the IP form with increasing pH; (vi) the reduced-minus-oxidized optical difference spectra of Cyt b(559) are very similar in the lambda range of 360-700 nm for all types except for the HP form which exhibits pronounced differences in the Soret band; and (vii) PS II membrane fragments and core complexes are inferred to contain about two Cyt b(559) hemes per PS II. Possible implications of conformational changes near the heme group and spin state transitions of the iron are discussed.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: (1) Redox Propertiesmentioning

confidence: 99%

Section: (1) Redox Propertiesmentioning

confidence: 99%

Section: (1) Redox Propertiesmentioning

confidence: 99%

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Redox and Spectral Properties of Cytochromeb₅₅₉in Different Preparations of Photosystem II

et al. 1999

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Photosynthetic Water Splitting: Apparatus and Mechanism

Ренгер

2011

Photosynthesis

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Effect of Dehydration on Light-Induced Reactions in Photosystem II: Photoreactions of Cytochrome b559

2003

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The effect of dehydration on the reaction pattern of photosystem II (PS II) has been studied by measuring and analyzing spectral changes induced by continuous wavelength illumination in films of untreated and hydroxylamine-washed PS II membrane fragments dehydrated to different levels. The obtained data revealed (i) the extent of light-induced formation of about one Q(A)(-*)per 230 chlorophylls (Chl) remains virtually invariant to dehydration down to the lowest values of relative humidity (6-8% RH); (ii) a decrease of the RH to 30% leads to severe blockage of the electron transfer from Q(A)(-*) to Q(B) and the progressive replacement of water oxidation by photooxidation of high potential (HP) cytochrome (Cyt) b559 in untreated PS II samples or accessory Chl and carotenoid (Car) molecules in samples with preoxidized Cyt b559; (iii) photooxidation of Cyt b559 is followed by its photoreduction, concomitant with photooxidation of Chl and Car; (iv) in dry samples with preoxidized Cyt b559, not more than a half of total Cyt b559 can be photochemically reduced, independent of the extent of Cyt b559 in the HP form; (v) at low RH values, Cyt b559 photoreduction in samples with preoxidized heme groups and photoaccumulation of Q(A)(-*) take place with biphasic kinetics with similar rate constants for both processes; (vi) Cyt b559 photoreduction in dry samples is DCMU insensitive, while the dark rereduction of photooxidized Cyt b559 is inhibited by DCMU; (vii) fast and slow kinetic phases of Cyt b559 photoreduction dramatically differ in their dependencies on the intensity of CW illumination and are associated with electron donation to Cyt b559 from Q(A)(-*) and pheophytin(-*), respectively. The pathways of light-induced electron transfer in PS II involving Cyt b559 are discussed.

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Structural Analysis of the Water: Plastoquinone Oxidoreductase from Spinach Thylakoids

Cited by 5 publications

References 14 publications

Redox and Spectral Properties of Cytochromeb₅₅₉in Different Preparations of Photosystem II

Redox and Spectral Properties of Cytochromeb₅₅₉in Different Preparations of Photosystem II

Photosynthetic Water Splitting: Apparatus and Mechanism

Effect of Dehydration on Light-Induced Reactions in Photosystem II: Photoreactions of Cytochrome b559

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Structural Analysis of the Water: Plastoquinone Oxidoreductase from Spinach Thylakoids

Cited by 5 publications

References 14 publications

Redox and Spectral Properties of Cytochromeb559in Different Preparations of Photosystem II

Redox and Spectral Properties of Cytochromeb559in Different Preparations of Photosystem II

Photosynthetic Water Splitting: Apparatus and Mechanism

Effect of Dehydration on Light-Induced Reactions in Photosystem II: Photoreactions of Cytochrome b559

Contact Info

Product

Resources

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Redox and Spectral Properties of Cytochromeb₅₅₉in Different Preparations of Photosystem II

Redox and Spectral Properties of Cytochromeb₅₅₉in Different Preparations of Photosystem II