Antagonistic Effects of α-Tocopherol and α-Tocoquinone in the Regulation of Cyclic Electron Transport around Photosystem II

1997 ◽  
Vol 52 (11-12) ◽  
pp. 766-774 ◽  
Author(s):  
J. Kruk ◽  
K. Burda ◽  
A. Radunz ◽  
K. Strzałka ◽  
G. H. Schmid
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Transition Probability ◽  
Continuous Illumination ◽  
Oxygen Evolving Complex ◽  
Cyclic Electron Transport ◽  
State Distribution ◽  
Ps Ii ◽  
Oxygen Evolving

Abstract α-Tocoquinone (α-TQ ) and α-tocopherol (α-TOC) which cannot substitute for plastoquinone-9 (PQ-A) as an electron acceptor from photosystem II (PS II), influence the oxygen evolution activity of thylakoid membranes under continuous illumination. In the presence of the herbicide DCMU and the protonophore FCCP which stimulate cyclic electron transport around PS II, α-TQ decreased oxygen evolution whereas α-TOC enhanced it. The effects are attributed to a stimulation or an inhibition of cyclic electron transport around PS II by α-TQ and α-TOC, respectively. Results of flash light experiments on PS II preparations show that both α-TQ and α-TOC increased the d-parameter which describes the transition probability from the S3- to the S0-state of the oxygen-evolving complex, although to a smaller extent when PQ-A is added alone to the preparations. The initial S-state distribution in darkadapted samples was changed only upon PQ-A addition and influenced neither by α-TQ nor by α-TO C supplementation. These effects indicate different kinds of interaction of PQ-A, α-TQ and α-TOC with the PS II components. α-TQ increased and α-TOC decreased the “total miss” parameter both in the presence or absence of PQ-A. A possible site of interaction of α-TQ and α-TO C with the cyclic electron transport around PS II is suggested.

Involvement of the Xanthophyll Cycle in Regulation of Cyclic Electron Flow around Photosystem II

1996 ◽  
Vol 51 (1-2) ◽  
pp. 47-52 ◽  
Author(s):  
W. I. Gruszecki ◽  
K. Strzałk ◽  
K.P. Bader ◽  
A. Radunz ◽  
G.H. Schmid
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Xanthophyll Cycle ◽  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Oxygen Evolution ◽  
Cyclic Electron Transport ◽  
Ps Ii ◽  
Low Levels

Abstract In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosynthetic apparatus by light is under control of the xanthophyll cycle. The combination of dif­ferent light quality and thylakoids having various levels of xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means of mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and of light-induced oxygen uptake indicate that the de-epoxidation of violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin.

Photoinactivation of Photosynthetic Electron Transport under Anaerobic and Aerobic Conditions in Isolated Thylakoids of Spinach

1992 ◽  
Vol 47 (1-2) ◽  
pp. 63-68 ◽  
Author(s):  
Rekha Chaturvedi ◽  
M. Singh ◽  
P. V. Sane
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Ps Ii ◽  
Ps I ◽  
S2 State ◽  
The Stability ◽  
Oxygen Evolving ◽  
Spinach Thylakoids

Abstract The effect of exposure to strong white light on photosynthetic electron transport reactions of PS I and PS II were investigated in spinach thylakoids in the absence or presence of oxygen. Irrespective of the conditions used for photoinactivation, the damage to PS II was always much more than to PS I. Photoinactivation was severe under anaerobic conditions compared to that in air for the same duration. This shows that the presence of oxygen is required for prevention of photoinactivation of thylakoids. The susceptibility of water-splitting complex in photoinactivation is indicated by our data from experiments with chloride-deficient chloroplast membranes wherein it was observed that the whole chain electron transport from DPC to MV was much less photoinhibited than that from water. The data from the photoinactivation experiments with the Tris-treated thylakoids indicate another photodam age site at or near reaction centre of PS II. DCMU-protected PS II and oxygen-evolving complex from photoinactivation. DCMU protection can also be interpreted in terms of the stability of the PS II complex when it is in S2 state.

Generalized approximate spin projection calculations of effective exchange integrals of the CaMn4O5 cluster in the S1 and S3 states of the oxygen evolving complex of photosystem II

2014 ◽  
Vol 16 (24) ◽  
pp. 11911-11923 ◽  
Author(s):  
H. Isobe ◽  
M. Shoji ◽  
S. Yamanaka ◽  
H. Mino ◽  
Y. Umena ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Symmetry Breaking ◽  
Oxygen Evolution ◽  
Broken Symmetry ◽  
Spin Projection ◽  
Oxygen Evolving Complex ◽  
Structural Symmetry ◽  
Effective Exchange ◽  
The Right ◽  
Oxygen Evolving

Broken-symmetry UB3LYP calculations have elucidated structural symmetry-breaking in the S1 and S3 states of the oxygen evolution complex (OEC) of photosystem II (PSII), providing the right (RO)- and left (LO)-opened structures.

Different sensitivities of photosystem II in green algae and cyanobacteria to phenylurea and phenol-type herbicides: effect on electron donor side

2017 ◽  
Vol 72 (7-8) ◽  
pp. 315-324 ◽  
Author(s):  
Ekaterina K. Yotsova ◽  
Martin A. Stefanov ◽  
Anelia G. Dobrikova ◽  
Emilia L. Apostolova
Keyword(s):  
Photosystem Ii ◽  
Kinetic Parameters ◽  
Oxygen Evolution ◽  
Oxygen Evolving Complex ◽  
Photosynthetic Oxygen Evolution ◽  
Donor Side ◽  
Short Term Treatment ◽  
Psii Photochemistry ◽  
Photosynthetic Oxygen ◽  
Oxygen Evolving

AbstractThe effects of short-term treatment with phenylurea (DCMU, isoproturon) and phenol-type (ioxynil) herbicides on the green algaChlorella kessleriand the cyanobacteriumSynechocystis salinawith different organizations of photosystem II (PSII) were investigated using pulse amplitude modulated (PAM) chlorophyll fluorescence and photosynthetic oxygen evolution measured by polarographic oxygen electrodes (Clark-type and Joliot-type). The photosynthetic oxygen evolution showed stronger inhibition than the PSII photochemistry. The effects of the studied herbicides on both algal and cyanobacterial cells decreased in the following order: DCMU>isoproturon>ioxynil. Furthermore, we observed that the number of blocked PSII centers increased significantly after DCMU treatment (204–250 times) and slightly after ioxynil treatment (19–35 times) in comparison with the control cells. This study suggests that the herbicides affect not only the acceptor side but also the donor side of PSII by modifications of the Mn cluster of the oxygen-evolving complex. We propose that one of the reasons for the different PSII inhibitions caused by herbicides is their influence, in different extents, on the kinetic parameters of the oxygen-evolving reactions (the initial S0−S1state distribution, the number of blocked centers SB, the turnover time of Sistates, misses and double hits). The relationship between the herbicide-induced inhibition and the changes in the kinetic parameters is discussed.

A Diterpene γ-Lactone Derivative from Pterodon polygalaeflorus Benth. as a Photosystem II Inhibitor and Uncoupler of Photosynthesis

2006 ◽  
Vol 61 (3-4) ◽  
pp. 227-233 ◽  
Author(s):  
Beatriz King-Díaz ◽  
Flávio J. L. dos Santos ◽  
Mayura M. M. Rubinger ◽  
Dorila Piló -Veloso ◽  
Blas Lotina-Hennsen
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Transport Rate ◽  
Atp Synthesis ◽  
Transport Rate ◽  
Hill Reaction ◽  
Oxygen Evolving Complex ◽  
Photosynthesis Inhibition ◽  
Chlorophyll A Fluorescence Transient ◽  
Oxygen Evolving

6α,7β-Dihydroxyvouacapan-17β-oic acid (1) was isolated from Pterodon polygalaeflorus Benth. Modification of 1 yielded 6α-hydroxyvouacapan-7β,17β-lactone (2) and then 6-oxovouacapan- 7β,17β-lactone (3). Photosynthesis inhibition by 3 was evaluated in spinach chloroplasts. The uncoupled non-cyclic electron transport rate and ATP synthesis were inhibited by 3, which behaved as a Hill reaction inhibitor. Furthermore, 3 acted as an uncoupler because it enhanced the basal and phosphorylating electron transport rate on thylakoids. This last property of 3 was corroborated when it was observed that it enhances the Mg2+-ATPase activity. In contrast, 3 did not affect photosystem I (PSI) activity. Analysis of the partial photosystem II (PSII) reactions from water to DCPIPox and water to silicomolybdate allowed to locate the inhibition sites at the redox components of PSII. The OJIP test of the chlorophyll a fluorescence transient confirmed that the inhibition sites were 1.) the oxygen-evolving complex (OEC) and 2.) by the formation of silent centers in the non-QA reducing centers.

Molecular evolutionary analysis of the psbP gene family of the photosystem II oxygen-evolving complex in Nicotiana

Genome ◽  
1993 ◽  
Vol 36 (3) ◽  
pp. 483-488 ◽  
Author(s):  
Shao-Bing Hua ◽  
Shyam K. Dube ◽  
Shain-dow Kung
Keyword(s):  
Molecular Evolution ◽  
Photosystem Ii ◽  
Gene Family ◽  
Oxygen Evolution ◽  
Oxygen Evolving Complex ◽  
Photosynthetic Oxygen Evolution ◽  
Evolutionary Analysis ◽  
Protein Patterns ◽  
Oxygen Evolving ◽  
Molecular Evolutionary Analysis

Photosystem II psbP protein of the oxygen-evolving complex is involved in the photosynthetic oxygen evolution in plants. Four psbP polypeptides were detected in Nicotiana tabacum on a two-dimensional gel by immunostaining the proteins with antiserum against the pea psbP Comparison of the protein patterns of psbP from N. tabacum and its ancestral parents, N. sylvestris and N. tomentosiformis, indicated that each of the ancestral parents has contributed a pair of psbP proteins. This was supported by Southern hybridization results, which suggested that psbP in Nicotiana is encoded by a gene family consisting of four members in N. tabacum and two members each in N. glauca, N. langsdorffii, N. sylvestris, and N. tomentosiformis. A scheme of molecular evolution of the psbP genes in Nicotiana is also proposed.Key words: molecular evolution, Nicotiana, oxygen evolution, photosystem II.

Surface structure of the photosystem II complex

1991 ◽  
Vol 49 ◽  
pp. 196-197
Author(s):  
Kenneth R. Miller ◽  
Jules S. Jacob
Keyword(s):  
Photosystem Ii ◽  
Photosynthetic Reaction Center ◽  
Oxygen Evolving Complex ◽  
Photosynthetic Membrane ◽  
Ps Ii ◽  
Quick Freezing ◽  
Inner Surface ◽  
Oxygen Evolving ◽  
Excellent Source ◽  
Photosynthetic Mutant

The Photosystem II (PS-II) complex is organized around a photosynthetic reaction center (RC) embedded in the photosynthetic membrane. PS-II traps the energy of sunlight and uses it drive highenergy electron transport across the photosynthetic membrane. PS-II is closely associated with a group of proteins known as the oxygen-evolving complex (OEC), which are bound to the inner surface of the photosynthetic membrane. This complex splits water to yield electrons that are passed to the RC, releasing molecular oxygen. We have used freeze-etch electron microscopy to study 2-dimensional crystals of the PS-II complex obtained from a photosynthetic mutant of barley (viridiszb63) kindly provided by Dr. David Simpson of the Carlsberg Institute of Copenhagen (Simpson & von Wettstein, 1980). The photosynthetic membranes of these mutant plants lack photosystem I, and consequently contain extensive crystalline membrane regions enriched in PS-II. These plants are an excellent source of PS-II sheetlike crystals, obtainable without the use of detergents or chemical modification: Figure 1, prepared by quick-freezing, deep-etching, and rotary shadowing, illustrates the appearance of these sheetlike crystals.

Catalytic Oxygen Evolution by a Bioinorganic Model of the Photosystem II Oxygen-Evolving Complex

2005 ◽  
Vol 82 (5) ◽  
pp. 791 ◽  
Author(s):  
Derrick L. Howard ◽  
Arthur D. Tinoco ◽  
Gary W. Brudvig ◽  
John S. Vrettos ◽  
Bertha Connie Allen
Keyword(s):  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Oxygen Evolving Complex ◽  
Oxygen Evolving

Blue Light-Enhanced Photosynthetic Oxygen Evolution from Liposome-Bound Photosystem II Particles; Possible Role of the Xanthophyll Cycle in the Regulation of Cyclic Electron Flow Around Photosystem II?

1995 ◽  
Vol 50 (1-2) ◽  
pp. 61-68 ◽  
Author(s):  
W. I. Gruszecki ◽  
K. Strzałka ◽  
A. Radunz ◽  
J. Kruk ◽  
G. H. Schmid
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Xanthophyll Cycle ◽  
Red Light ◽  
Photosynthetic Oxygen Evolution ◽  
Reaction Centre ◽  
Ps Ii ◽  
Photosynthetic Oxygen ◽  
Β Carotene

Abstract Light-driven electron transport in liposome-bound photosystem II (PS-II) particles be­tween water and ferricyanide was monitored by bare platinum electrode oxymetry. The modi­fication of the experimental system with the exogenous quinones α-tocopherol quinone ( α-TQ) or plastoquinone (PQ) resulted in a pronounced effect on photosynthetic oxygen evolution. The presence of α-tocopherolquinone ( α-TQ) in PS-II samples decreased the rate of red light-induced oxygen evolution but increased the rate of green light-induced oxygen evolution. Blue light applied to the assay system in which oxygen evolution was saturated by red light resulted in a further increase of the oxygen signal. These findings are interpreted in terms of a cyclic electron transport around PS-II, regulated by an excitation state of β-carotene in the reaction centre of PS-II. A mechanism is postulated according to which energetic coupling of β-carotene in the reaction centre of PS-II and that of other antenna carotenoid pigments is regulated by the portion of the xanthophyll violaxanthin, which is under control of the xanthophyll cycle.

Effect of an Antiserum to a Thylakoid Membrane Polypeptide on the Primary Photoreaction of Photosystem II

1976 ◽  
Vol 31 (9-10) ◽  
pp. 594-600 ◽  
Author(s):  
Georg H. Schmid ◽  
Gernot Renger ◽  
Michael Gläser ◽  
Friederike Koenig ◽  
Alfons Radunz ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Electron Flow ◽  
Primary Electron ◽  
Hill Reaction ◽  
Ps Ii ◽  
Absorption Change ◽  
Oxygen Evolving ◽  
The Hill

Abstract As was described previously, an antiserum to polypeptide 11000 inhibited photosynthetic elec­tron transport on the oxygen evolving side of photosystem II. The effect of the antiserum on chloro­plasts from two tobacco mutants also clearly showed that the inhibition site is on the photosystem II-side of the electron transport chain. One of the two tobacco mutants lades the oxygen evolving capacity but exhibits some electron transport with tetramethyl benzidine, an artificial donor to PS II. In this mutant electron transport was barely inhibited. The effect of the antiserum on the primary photoevents showed that the initial amplitude of the absorption change of chlorophyll an at 690 nm and that of the primary electron acceptor X320 at 334 nm both diminished in the presence of the antiserum. Both signals were restored upon addition of diphenylcarbazide another artificial donor to photosystem II. Comparison of the degree of inhibition on the amplitudes of the fast and slow components of the 690 nm absorption change with the manometrically measured inhibition of electron transport shows that besides a full inactivation of a part of the reaction centers of photosystem II another part apparently mediates a fast cyclic electron flow around photosystem II as reported by Renger and Wolff earlier for tris-treated chloroplasts. Moreover, the antiserum affects the low temperature fluorescence in a way which is opposite to Murata’s effect of the Mg2+ -ion induced inhibition of energy spill-over from photosystem II to photosystem I. The antiserum under the condition in which the Hill reaction is inhibited lowered the 686 nm emission and enhanced the 732 nm emission which indicates an enhanced energy spill-over to photosystem I.

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