Turn-over of electron donors in Photosystem I: Double-flash experiments with pea chloroplasts and Photosystem I particles

1987 ◽  
Vol 892 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Hervé Bottin ◽  
Paul Mathis
Keyword(s):  
Photosystem I ◽  
Electron Donors ◽  
Turn Over ◽  
Double Flash

The study of oxygen reduction in photosystem I of higher plants using electron donors for this photosystem in intact thylakoids

2015 ◽  
Vol 9 (4) ◽  
pp. 246-251 ◽  
Author(s):  
M. A. Kozuleva ◽  
D. V. Vetoshkina ◽  
A. A. Petrova ◽  
M. M. Borisova-Mubarakshina ◽  
B. N. Ivanov
Keyword(s):  
Oxygen Reduction ◽  
Photosystem I ◽  
Higher Plants ◽  
Electron Donors

Cyanobacterial Photosystem I lacks specificity in its interaction with cytochrome c6 electron donors

2005 ◽  
Vol 83 (3) ◽  
pp. 329-333 ◽  
Author(s):  
Manuel Hervás ◽  
Antonio Díaz-Quintana ◽  
Cheryl A. Kerfeld ◽  
David W. Krogmann ◽  
Miguel A. De la Rosa ◽  
...  
Keyword(s):  
Photosystem I ◽  
Electron Donors ◽  
Cytochrome C6

Model systems for photosynthesis. VII. Chlorophyll a photosensitized reduction of methyl viologen by hydroquinones

1980 ◽  
Vol 373 (1753) ◽  
pp. 179-187 ◽  
Keyword(s):  
Ascorbic Acid ◽  
Chlorophyll A ◽  
Photosystem I ◽  
Methyl Viologen ◽  
Empirical Relation ◽  
Electron Donors ◽  
Model Systems ◽  
Cyclic Process ◽  
Subsequent Reaction ◽  
Permanent Storage

The use of hydroquinones as electron donors for in vitro models of Photosystem I has been investigated. Excited chlorophyll a (Chi*) was first reacted with methyl viologen (MV 2+ ) to give ChI + and MV t . The subsequent reaction of ChI t with hydroquinones was slower than the comparable reaction with alternative electron donors such as cysteine or ascorbic acid, and an empirical relation was observed between the redox potential of the hydroquinone and the rate constant for its reaction with ChI t . This sequence of reactions stores 40 % of the energy available in the chlorophyll a triplet state, but no permanent storage of energy was achieved since MV t back-reacts with quinone to give a cyclic process.

scholarly journals Theoretical Assessment of Hinge-Type Models for Electron Donors in Reaction Centers of Photosystems I and II as Well as of Purple Bacteria

2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Jörg Matysik ◽  
Johannes Neugebauer
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Purple Bacteria ◽  
High Sensitivity ◽  
Reaction Centers ◽  
Electron Donors ◽  
Molecular Systems ◽  
Density Distributions ◽  
Theoretical Assessment ◽  
Spin Densities

Hinge-type molecular models for electron donors in reaction centers of Photosystem I, II, and purple bacteria were investigated using a two-state computational approach based on Frozen-Density Embedding. This methodology, dubbed FDE-diab, is known to avoid consequences of the self-interaction error as far as intermolecular phenomena are concerned, which allows to predict qualitatively correct spin densities for large bio-molecular systems. The calculated spin density distributions are in a good agreement with available experimental results and demonstrated a very high sensitivity to changes in relative orientiation of co-factors and amino-acid protonation states. This allows to validate the previously proposed hinge-type models and make predictions on protonation states of axial histidine molecules. Contrary to the reaction centers in Photosystem I and purple bacteria, the axial histidines from Photosystem II were found to be deprotonated. This fact might shed some light on remarkable properties of Photosystem II reaction centers.

scholarly journals Theoretical Assessment of Hinge-Type Models for Electron Donors in Reaction Centers of Photosystems I and II as Well as of Purple Bacteria

2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Jörg Matysik ◽  
Johannes Neugebauer
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Purple Bacteria ◽  
High Sensitivity ◽  
Reaction Centers ◽  
Electron Donors ◽  
Molecular Systems ◽  
Density Distributions ◽  
Theoretical Assessment ◽  
Spin Densities

Hinge-type molecular models for electron donors in reaction centers of Photosystem I, II, and purple bacteria were investigated using a two-state computational approach based on Frozen-Density Embedding. This methodology, dubbed FDE-diab, is known to avoid consequences of the self-interaction error as far as intermolecular phenomena are concerned, which allows to predict qualitatively correct spin densities for large bio-molecular systems. The calculated spin density distributions are in a good agreement with available experimental results and demonstrated a very high sensitivity to changes in relative orientiation of co-factors and amino-acid protonation states. This allows to validate the previously proposed hinge-type models and make predictions on protonation states of axial histidine molecules. Contrary to the reaction centers in Photosystem I and purple bacteria, the axial histidines from Photosystem II were found to be deprotonated. This fact might shed some light on remarkable properties of Photosystem II reaction centers.

scholarly journals Crystal structures of virus-like photosystem I complexes from the mesophilic cyanobacterium Synechocystis PCC 6803

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Yuval Mazor ◽  
Daniel Nataf ◽  
Hila Toporik ◽  
Nathan Nelson
Keyword(s):  
Photosystem I ◽  
Life Forms ◽  
Antenna System ◽  
Electron Donors ◽  
Oxygenic Photosynthesis ◽  
Synechocystis Pcc 6803 ◽  
Transport Chain ◽  
Marine Viruses ◽  
Cyanobacteria And Algae ◽  
First Time

Oxygenic photosynthesis supports virtually all life forms on earth. Light energy is converted by two photosystems—photosystem I (PSI) and photosystem II (PSII). Globally, nearly 50% of photosynthesis takes place in the Ocean, where single cell cyanobacteria and algae reside together with their viruses. An operon encoding PSI was identified in cyanobacterial marine viruses. We generated a PSI that mimics the salient features of the viral complex, named PSIPsaJF. PSIPsaJF is promiscuous for its electron donors and can accept electrons from respiratory cytochromes. We solved the structure of PSIPsaJF and a monomeric PSI, with subunit composition similar to the viral PSI, providing for the first time a detailed description of the reaction center and antenna system from mesophilic cyanobacteria, including red chlorophylls and cofactors of the electron transport chain. Our finding extends the understanding of PSI structure, function and evolution and suggests a unique function for the viral PSI.

scholarly journals Cobalt Complexes of Polypyridyl Ligands for the Photocatalytic Hydrogen Evolution Reaction

2021 ◽  
Vol 75 (3) ◽  
pp. 180-187
Author(s):  
Evelyne Joliat-Wick ◽  
Mathias Mosberger ◽  
Nicola Weder ◽  
Bernhard Spingler ◽  
Benjamin Probst ◽  
...  
Keyword(s):  
Photosystem I ◽  
Hydrogen Evolution Reaction ◽  
Kinetic Data ◽  
Heterogeneous Systems ◽  
Cobalt Complexes ◽  
Electron Donors ◽  
Polypyridyl Ligands ◽  
Electron Relays ◽  
Reduction Catalysts ◽  
Selection Of

The reductive part of artificial photosynthesis, the reduction of protons into H2, is a two electron two proton process. It corresponds basically to the reactions occurring in natural photosystem I. We show in this review a selection of involved processes and components which are mandatory for making this light-driven reaction possible at all. The design and the performances of the water reduction catalysts is a main focus together with the question about electron relays or sacrificial electron donors. It is shown how an original catalyst is developed into better ones and what it needs to move from purely academic homogeneous processes to heterogeneous systems. The importance of detailed mechanistic knowledge obtained from kinetic data is emphasized.

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