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.

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.

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

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.

Large-scale QM/MM calculations of the CaMn4O5 cluster in the S3 state of the oxygen evolving complex of photosystem II. Comparison between water-inserted and no water-inserted structures

2017 ◽  
Vol 198 ◽  
pp. 83-106 ◽  
Author(s):  
Mitsuo Shoji ◽  
Hiroshi Isobe ◽  
Takahito Nakajima ◽  
Yasuteru Shigeta ◽  
Michihiro Suga ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Large Scale ◽  
Geometrical Structure ◽  
Bond Formation ◽  
Oxygen Evolving Complex ◽  
Computational Results ◽  
Hydroxide Anion ◽  
The Right ◽  
Oxygen Evolving

Large-scale QM/MM calculations were performed to elucidate an optimized geometrical structure of a CaMn4O5 cluster with and without water insertion in the S3 state of the oxygen evolving complex (OEC) of photosystem II (PSII). The left (L)-opened structure was found to be stable under the assumption of no hydroxide anion insertion in the S3 state, whereas the right (R)-opened structure became more stable if one water molecule is inserted to the Mn4Ca cluster. The optimized Mna(4)–Mnd(1) distance determined by QM/MM was about 5.0 Å for the S3 structure without an inserted hydroxide anion, but this is elongated by 0.2–0.3 Å after insertion. These computational results are discussed in relation to the possible mechanisms of O–O bond formation in water oxidation by the OEC of PSII.

scholarly journals Inhibition of oxygen evolution in Photosystem II by Cu(II) ions is associated with oxidation of cytochrome b559

2003 ◽  
Vol 371 (2) ◽  
pp. 597-601 ◽  
Author(s):  
Kvetoslava BURDA ◽  
Jerzy KRUK ◽  
Georg H. SCHMID ◽  
Kazimierz STRZALKA
Keyword(s):  
Photosystem Ii ◽  
Fluorescence Quenching ◽  
Oxygen Evolution ◽  
Copper Ions ◽  
Oxygen Evolving Complex ◽  
Cytochrome B559 ◽  
Low Concentrations ◽  
Target Sites ◽  
Potential Form ◽  
Oxygen Evolving

We have found that elevated copper concentrations, apart from the inhibition of oxygen evolution, changed the initial states distribution of the oxygen-evolving complex. Already at low concentrations, copper ions oxidized the low-potential form of cytochrome b559 and also its high-potential form at higher concentrations at which fluorescence quenching was observed. We suggest that the primary target sites in Photosystem II for copper is tyrosinez, both cytochrome b559 forms and chlorophyllz, and that these sites are the source of the copper-induced fluorescence quenching and oxygen evolution inhibition in Photosystem II.

Hyperfine tensors for a model system for the oxygen evolving complex of photosystem II: calculation of the anisotropy shift that occurs beyond the strong exchange limit

2019 ◽  
Vol 21 (41) ◽  
pp. 22902-22909
Author(s):  
Christine Mehlich ◽  
Christoph van Wüllen
Keyword(s):  
Photosystem Ii ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Mixed Valence ◽  
Model System ◽  
Manganese Complex ◽  
Broken Symmetry ◽  
Oxygen Evolving Complex ◽  
Strong Exchange ◽  
Oxygen Evolving

Broken-symmetry density functional calculations have been used to calculate effective 55Mn hyperfine (A) tensors for a mixed-valence tetranuclear manganese complex, a model system for the S2 state of the oxygen-evolving complex of photosystem II.

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