Kinetics of oxygen evolution from hydrogen peroxide catalyzed by an oxygen-evolving complex: investigation of the S1-dependent reaction

Biochemistry ◽  
1987 ◽  
Vol 26 (23) ◽  
pp. 7321-7325 ◽  
Author(s):  
Wayne D. Frasch ◽  
Rui Mei
Keyword(s):  
Hydrogen Peroxide ◽  
Oxygen Evolution ◽  
Oxygen Evolving Complex ◽  
Complex Investigation ◽  
Oxygen Evolving ◽  
Kinetics Of

scholarly journals Photosystem II: Thermodynamics and Kinetics of Electron Transport from QA- to QB(QB- ) and Deleterious Effects of Copper(II)

1993 ◽  
Vol 48 (3-4) ◽  
pp. 234-240 ◽  
Author(s):  
G. Renger ◽  
H. M. Gleiter ◽  
E. Haag ◽  
F. Reifarth
Keyword(s):  
Oxygen Evolution ◽  
Manganese Content ◽  
Fluorescence Emission ◽  
Laser Flash ◽  
Fluorescence Induction ◽  
Oxygen Evolving Complex ◽  
Ps Ii ◽  
Thermodynamics And Kinetics ◽  
Redox Active ◽  
Kinetics Of

Studies on thermodynamics and kinetics of electron transfer from QA- to QB(QB-) were performed by monitoring laser flash induced changes of the relative fluorescence emission as a function of temperature (220 K < T < 310 K) in isolated thylakoids and PS II membrane fragments.In addition, effects of bivalent metal ions on PS II were investigated by measuring conventional fluorescence induction curves, oxygen evolution, manganese content and atrazine binding mostly in PS II membrane fragments. It was found: a) the normalized level of the fluorescence remaining 10 s after the actinic flash (Ft/F0) steeply increases at temperatures below -10 to - 20 °C, b) the fast phase of the transient fluorescence change becomes markedly retarded with decreasing temperatures, c) among different cations (Cu2+, Zn2+, Cd2+, Ni2+, Co2+) only Cu2+ exhibits marked effects in the concentration range below 100 μᴍ and d) Cu2+ decreases the normalized variable fluorescence, inhibits oxygen evolution and diminishes the affinity to atrazine binding without affecting the number of binding sites. The content of about four manganeses per functionally competent oxygen evolving complex is not changed by [Cu2+] < 70 μᴍ.Based on these findings it is concluded: i) a temperature dependent equilibrium between an inactive (I) and active (A) state of QA- reoxidation by QB(QB- ) is characterized by standard enthalpies ΔH° of 95 kJ mol-1 and 60 kJ mol-1 and standard entropies ΔS° of 370 kJ K-1 mol-1 and 240 kJ K-1 mol-1 in isolated thylakoids and PS II membrane fragments, respectively, ii) the activation energies of QA- reoxidation by plastoquinone bound to the QB site are about 30 kJ mol-1 (thylakoids) and 40 kJ mol-1 (PS II membrane fragments) in 220 K < T < 300 K, and iii) Cu2+ causes at least a two-fold effect on PS II by modifying the atrazine binding affinity at lower concentrations ( ~ 5 μᴍ) and interference with the redox active tyrosine Yz at slightly higher concentration ( ~ 10 μᴍ) leading to blockage of oxygen evolution.

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.

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