Regulation of Photosynthetic Electron Transport via Supercomplex Formation in the Thylakoid Membrane

2015 ◽  
pp. 167-186
Author(s):  
Kentaro Ifuku ◽  
Toshiharu Shikanai
Keyword(s):  
Electron Transport ◽  
Thylakoid Membrane ◽  
Photosynthetic Electron Transport

Localization and Function of Cytochrome f in the Thylakoid Membrane

1977 ◽  
Vol 32 (3-4) ◽  
pp. 271-280 ◽  
Author(s):  
Georg H. Schmid ◽  
Alfons Radunz ◽  
Wilhelm Menke
Keyword(s):  
Electron Transport ◽  
Outer Surface ◽  
Thylakoid Membrane ◽  
Time Lag ◽  
Photosynthetic Electron Transport ◽  
Cytochrome F ◽  
Antigenic Determinants ◽  
Light Reaction ◽  
Transport Reaction ◽  
Cyclic Photophosphorylation

Abstract A monospecific antiserum to cytochrome f agglutinates stroma-free swellable chloroplasts from tobacco and Antirrhinum. Consequently, antigenic determinants towards which the antiserum is directed are located in the outer surface of the thylakoid membrane. The antiserum inhibits linear photosynthetic electron transport. Just as described earlier for the antiserum to polypeptide 11000 this inhibition develops in the course of the light reaction. Ultrasonication in the presence of anti­ serum abolishes the light requirement and the maximal inhibition of the electron transport reaction is immediately observed. Electron transport in chloroplasts from a tobacco mutant which ex­ hibits only photosystem I-reactions is also inhibited by the antiserum. No time lag in the light for the onset of inhibition is observed with these chloroplasts. As chloroplasts of this mutant have only single unfolded thylakoids it appears that light might preponderantly open up partitions. If the light effect is interpreted in this way, cytochrome f should be located in the partition regions but nevertheless in the outer surface of the thylakoid membrane. However, a rearrangement of molecules in the membrane in the light by which the accessibility of cytochrome f is changed can­ not be excluded. The inhibition of linear electron transport by the antiserum is approximately 50 per cent and can only be increased to 75% upon the addition of antibodies to plastocyanin. The inhibition by the antiserum to cytochrome f as well as the combined inhibition by the antisera to cytochrome f and plastocyanin can be by-passed by DCPiP. It appears that cytochrome f and plastocyanin cannot be connected in series in the electron transport chain but are both closely associated in the thylakoid membrane. PMS-mediated cyclic photophosphorylation in chloroplasts from wild type tobacco and the tobacco mutant NC95 is only inhibited if the chloroplasts are sonicated in the presence of anti­ serum. If one disregards, that ultrasonication might cause reaction artifacts, it is thinkable that the cytochrome f, involved in the PMS-mediated cyclic photophosphorylation reaction, might be located inside the membrane.

The Effect of Antibodies to Violaxanthin on Photosynthetic Electron Transport

1979 ◽  
Vol 34 (5-6) ◽  
pp. 427-430 ◽  
Author(s):  
Ursula Lehmann-Kirk ◽  
Georg H. Schmid ◽  
Alfons Radunz
Keyword(s):  
Electron Transport ◽  
Thylakoid Membrane ◽  
Specific Binding ◽  
Photosynthetic Electron Transport ◽  
Antigenic Determinants ◽  
Coombs Test ◽  
Diphenyl Carbazide ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain ◽  
Oxygen Evolving

Abstract An antiserum to violaxanthin in hibits photosynthetic electron transport between water, iodide or tetramethylbenzidine and various electron acceptors in chloroplasts from green tobacco (Nicotian a tabacum var. John William’s Broadleaf). However, electron transport from manganese or diphenyl-carbazide to these acceptors is not impaired. The typical photosystem I reaction from DPIP / ascorbate to anthraquinone-2-sulfonate in the presence of DCMU shows no inhibition. From this it is concluded that the effect of violaxanthin on the photosynthetic electron transport chain lies on the oxygen-evolving side of photosystem II before the site from which diphenylcarbazide or manganese donate electrons.In the presence of DCMU after preillumination we find an effect of the antiserum on fluorescence.The reaction of the antibodies to violaxanthin with stroma-freed chloroplasts depends on the condition of the thylakoid membrane. Chloroplasts which are still swellable react in a bivalent manner and are agglutinated. Non swellable chloroplasts react only in a monovalent manner. This specific binding was demonstrated by means of the Coombs-test.From these reactions it follows that the antigenic determinants of violaxanthin are accessible to the antibodies, hence, they must be located in the outer surface of the thylakoid membrane.

Formation mechanisms of superoxide radical and hydrogen peroxide in chloroplasts, and factors determining the signalling by hydrogen peroxide

2018 ◽  
Vol 45 (2) ◽  
pp. 102 ◽  
Author(s):  
Boris N. Ivanov ◽  
Maria M. Borisova-Mubarakshina ◽  
Marina A. Kozuleva
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transport ◽  
Thylakoid Membrane ◽  
Electron Transport Chain ◽  
Superoxide Radical ◽  
Photosynthetic Electron Transport ◽  
Formation Mechanisms ◽  
H2o2 Production ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Reduction of O2 molecule to superoxide radical, O2•−, in the photosynthetic electron transport chain is the first step of hydrogen peroxide, H2O2, production in chloroplasts in the light. The mechanisms of O2 reduction by ferredoxin, by the components of the plastoquinone pool, and by the electron transfer cofactors in PSI are analysed. The data indicating that O2•− and H2O2 can be produced both outside and within thylakoid membrane are presented. The H2O2 production in the chloroplast stroma is described as a result of either dismutation of O2•− or its reduction by stromal reductants. Formation of H2O2 within thylakoid membrane in the reaction of O2•− with plastohydroquinone is examined. The significance of both ways of H2O2 formation for specificity of the signal being sent by photosynthetic electron transport chain to cell adaptation systems is discussed.

Binding of Antibodies onto the Thylakoid Membrane III. Proteins in the Outer Surface of the Thylakoid Membrane

1978 ◽  
Vol 33 (9-10) ◽  
pp. 731-734 ◽  
Author(s):  
Alfons Radunz
Keyword(s):  
Molecular Weight ◽  
Electron Transport ◽  
Outer Surface ◽  
Thylakoid Membrane ◽  
Apparent Molecular Weight ◽  
Photosynthetic Electron Transport ◽  
Coupling Factor ◽  
Cytochrome F ◽  
Threefold Increase ◽  
Close Relationship

Abstract The maximal binding of antibodies to ferredoxin-NADP+ -reductase, cytochrome f, plastocyanin, coupling factor of photophosphorylation, carboxydismutase and to a polypeptide with the apparent molecular weight 24 000 onto stroma-freed chloroplasts of Antirrhinum majus was determined. The three proteins involved in photosynthetic electron transport bind approximately 0.05 to 0.07 g antibodies per g chloroplasts. The chloroplast preparation itself binds maximally about 1 gantibodies. From an antiserum to carboxydismutase and to a membrane polypeptide with the apparent molecular weight 24 000 approximately double the amount of antibodies namely 0.1 to 0.14 g antibodies per g chloroplasts are bound. Extraction of stroma-freed chloroplasts with 0.02 ᴍ Tris buffer pH 7.8 containing 0.7 mᴍ EDTA caused a threefold increase of the amount of bound anti­ bodies in the case of the membrane protein. 40% of the amount of antibodies which can be maxi­mally bound by this chloroplast preparation is adsorbed out of an antiserum to the coupling factor.Out of an antiserum which contains equal concentrations of antibodies to ferredoxin-NADP+ -reductase, cytochrome f and plastocyanin the same amount of antibodies is bound as out of an antiserum directed to only one of these components. This shows that the proteins involved in electron transport are located in a very close relationship to each other in the outer surface of the thylakoid membrane.

Miltiparticle computer simulation of photosynthetic electron transport in the thylakoid membrane

BIOPHYSICS ◽  
2007 ◽  
Vol 52 (5) ◽  
pp. 481-488 ◽  
Author(s):  
I. B. Kovalenko ◽  
A. M. Abaturova ◽  
D. M. Ustinin ◽  
G. Yu. Riznichenko ◽  
E. A. Grachev ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Electron Transport ◽  
Thylakoid Membrane ◽  
Photosynthetic Electron Transport
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