scholarly journals Novel structural aspect of the diatom thylakoid membrane: lateral segregation of photosystem I under red-enhanced illumination

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
David Bína ◽  
Miroslava Herbstová ◽  
Zdenko Gardian ◽  
František Vácha ◽  
Radek Litvín
Keyword(s):  
Photosystem I ◽  
Thylakoid Membrane ◽  
Structural Aspect ◽  
Lateral Segregation

Shuttles of Artificial Electron Donors for Photosystem I Across the Thylakoid Membrane

1975 ◽  
Vol 30 (1-2) ◽  
pp. 37-45 ◽  
Author(s):  
G. Hauska ◽  
W. Oettmeier ◽  
S. Reimer ◽  
A. Trebst
Keyword(s):  
Photosystem I ◽  
Thylakoid Membrane ◽  
Energy State ◽  
High Energy ◽  
Atp Formation ◽  
External Oxidation ◽  
Transport Control ◽  
Energy Conserving ◽  
High Energy State ◽  
Isolated Chloroplasts

Abstract NADP+ reduction in isolated chloroplasts of spinach by photosystem I at the expense of various artificial donor systems is not inhibited by the plastoquinone antagonist dibromothymoquinone. The coupled ATP formation in such photoreductions is attributed to an artificial energy conserving site, i. e. a proton liberation during oxidation of the donor at the inner surface of the thylakoid membrane. Some donor systems for photosystem I are stimulated by uncouplers whereas others are not. The stimulation shows no correlation to the efficiency of the coupled photophosphorylation. Instead a correlation of the stimulation by uncouplers to the presence of an acidic OH-group in the donor molecule is seen. The uncoupler effect is therefore not explained by a release of electron transport control by the high energy state but rather by a pH-dependent distribution of the donor compound across the membrane. This is supported by the properties of donor systems in sonicated chloroplast particles with external oxidation sites of photosystem I.

Polypeptides of the Thylakoid Membrane and Their Functional Characterization

1978 ◽  
Vol 33 (9-10) ◽  
pp. 723-730 ◽  
Author(s):  
Georg H. Schmid ◽  
Wilhelm Menke ◽  
Alfons Radunz ◽  
Friederike Koenig
Keyword(s):  
Molecular Weight ◽  
Electron Transport ◽  
Electron Donor ◽  
Photosystem I ◽  
Thylakoid Membrane ◽  
Apparent Molecular Weight ◽  
Variable Fluorescence ◽  
Phenazine Methosulfate ◽  
Cyclic Photophosphorylation ◽  
High Concentrations

Abstract From stroma-freed chloroplasts of Antirrhinum majus polypeptides with the apparent molecular weights 44 000, 26 000 and 20 000 were isolated.The antiserum to a polypeptide with the moleculair weight 44 000 inhibits the photoreduction of anthraquinone-2-sulfonate with dichlorophenol indophenol/ascorbate when the concentration of the electron donor dichlorophenol indophenol is low. The antiserum enhances the rate of phenazine methosulfate-mediated cyclic photophosphorylation. The variable fluorescence yield is increased by the antiserum . It is assumed that this polypeptide plays a role in electron transport between the two photosystems. From two polypeptides with the apparent molecular weight 26 000 one seems to belong to the reaction center of photosystem II as it inhibits the photooxidation of tetramethyl benzidine and diphenyl carbazide with suitable electron acceptors and inhibits electron transport between water and silicomolybdate. Variable fluorescence is not or not too strong decreased by the antiserum . The other polypeptide of the apparent molecular weight 26 000 inhibits the photoreduction of anthraquinone-2-sulfonate with high concentrations of dichlorophenol indophenol as the electron donor. Phenazine methosulfate-mediated cyclic photophosphorylation is also inhibited by the antiserum . Therefore, we should like to associate it with the reaction center of photosystem I. The antiserum to the polypeptide with the apparent molecular weight 20 000 inhibits the photoreduction of anthraquinone-2-sulfonate with low and high concentrations of the electron donor dichlorophenol indophenol. It enhances phenazine methosulfate-mediated cyclic photophosphorylation. The polypeptide, therefore, should be functionally involved on the acceptor side of photosystem I.The results obtained up-to-now on the function and localization of the polypeptides in the thylakoid membrane are summarized.

scholarly journals Tetratricopeptide repeat protein protects photosystem I from oxidative disruption during assembly

2016 ◽  
Vol 113 (10) ◽  
pp. 2774-2779 ◽  
Author(s):  
Mark Heinnickel ◽  
Rick G. Kim ◽  
Tyler M. Wittkopp ◽  
Wenqiang Yang ◽  
Karim A. Walters ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Chlamydomonas Reinhardtii ◽  
Photosystem I ◽  
Thylakoid Membrane ◽  
Redox State ◽  
Tetratricopeptide Repeat ◽  
Wild Type ◽  
Repeat Protein ◽  
Tetratricopeptide Repeat Protein ◽  
History Of

A Chlamydomonas reinhardtii mutant lacking CGL71, a thylakoid membrane protein previously shown to be involved in photosystem I (PSI) accumulation, exhibited photosensitivity and highly reduced abundance of PSI under photoheterotrophic conditions. Remarkably, the PSI content of this mutant declined to nearly undetectable levels under dark, oxic conditions, demonstrating that reduced PSI accumulation in the mutant is not strictly the result of photodamage. Furthermore, PSI returns to nearly wild-type levels when the O2 concentration in the medium is lowered. Overall, our results suggest that the accumulation of PSI in the mutant correlates with the redox state of the stroma rather than photodamage and that CGL71 functions under atmospheric O2 conditions to allow stable assembly of PSI. These findings may reflect the history of the Earth’s atmosphere as it transitioned from anoxic to highly oxic (1–2 billion years ago), a change that required organisms to evolve mechanisms to assist in the assembly and stability of proteins or complexes with O2-sensitive cofactors.

Correlation of the Photosynthetic Reduction of ρ-(Diazonium-)Benzenesulfonic Acid with the Increased Binding of the Probe to the Thylakoid Membrane

1976 ◽  
Vol 31 (1-2) ◽  
pp. 48-54 ◽  
Author(s):  
Wolfgang Lockau ◽  
Bruce R. Selman
Keyword(s):  
Electron Transport ◽  
Oxygen Uptake ◽  
Conformational Change ◽  
Photosystem I ◽  
Thylakoid Membrane ◽  
Sulfonic Acid ◽  
Benzenesulfonic Acid ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Labeled Probe

Abstract The reactions of chloroplast thylakoid lamellae with the chemical probe ρ-(diazonium-) benzene­ sulfonic acid (DABS) in the light have been reinvestigated. In contrast to a previous report, electron transport from a photosystem I electron donor to methylviologen was found to be inhibited by this treatment. During the incubation of chloroplasts with DABS in the light, the probe is altered with high rates. Under aerobic conditions, a concomitant oxygen uptake is observed, which is stoichiometric to the amount of DABS altered. Under anaerobic conditions, the binding of the 35S-labeled probe to the membranes in the light is stimulated 2 - 3 fold as compared to the binding under aerobic conditions. The data are taken as evidence that the photoreduction of the probe rather than a conformational change of the membrane may be at least partially responsible for the increased reagent binding observed in the light.

scholarly journals Lateral Segregation of Photosystem I in Cyanobacterial Thylakoids

2017 ◽  
Vol 29 (5) ◽  
pp. 1119-1136 ◽  
Author(s):  
Craig MacGregor-Chatwin ◽  
Melih Sener ◽  
Samuel F.H. Barnett ◽  
Andrew Hitchcock ◽  
Meghan C. Barnhart-Dailey ◽  
...  
Keyword(s):  
Photosystem I ◽  
Lateral Segregation

scholarly journals Gross morphological changes in thylakoid membrane structure are associated with photosystem I deletion in Synechocystis sp. PCC 6803

2012 ◽  
Vol 1818 (5) ◽  
pp. 1427-1434 ◽  
Author(s):  
Allison M.L. van de Meene ◽  
William P. Sharp ◽  
Jennifer H. McDaniel ◽  
Heiner Friedrich ◽  
Wim F.J. Vermaas ◽  
...  
Keyword(s):  
Photosystem I ◽  
Thylakoid Membrane ◽  
Membrane Structure ◽  
Morphological Changes ◽  
Synechocystis Sp ◽  
Pcc 6803
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