Photooxidation of Mn-bicarbonate Complexes by Reaction Centers of Purple Bacteria as a Possible Stage in the Evolutionary Origin of the Water-Oxidizing Complex of Photosystem II

2015 ◽  
pp. 85-132 ◽  
Author(s):  
Vasily V. Terentyev ◽  
Andrey A. Khorobrykh ◽  
Vyacheslav V. Klimov
Keyword(s):  
Photosystem Ii ◽  
Purple Bacteria ◽  
Reaction Centers ◽  
Evolutionary Origin ◽  
Water Oxidizing Complex

scholarly journals Structural Basis of Cyanobacterial Photosystem II Inhibition by the Herbicide Terbutryn

2011 ◽  
Vol 286 (18) ◽  
pp. 15964-15972 ◽  
Author(s):  
Matthias Broser ◽  
Carina Glöckner ◽  
Azat Gabdulkhakov ◽  
Albert Guskov ◽  
Joachim Buchta ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Purple Bacteria ◽  
Chloride Ion ◽  
Reaction Centers ◽  
Structural Basis ◽  
Photosynthetic Reaction Centers ◽  
Thermophilic Cyanobacterium ◽  
Herbicide Binding ◽  
Water Oxidizing Complex

Herbicides that target photosystem II (PSII) compete with the native electron acceptor plastoquinone for binding at the QB site in the D1 subunit and thus block the electron transfer from QA to QB. Here, we present the first crystal structure of PSII with a bound herbicide at a resolution of 3.2 Å. The crystallized PSII core complexes were isolated from the thermophilic cyanobacterium Thermosynechococcus elongatus. The used herbicide terbutryn is found to bind via at least two hydrogen bonds to the QB site similar to photosynthetic reaction centers in anoxygenic purple bacteria. Herbicide binding to PSII is also discussed regarding the influence on the redox potential of QA, which is known to affect photoinhibition. We further identified a second and novel chloride position close to the water-oxidizing complex and in the vicinity of the chloride ion reported earlier (Guskov, A., Kern, J., Gabdulkhakov, A., Broser, M., Zouni, A., and Saenger, W. (2009) Nat. Struct. Mol. Biol. 16, 334–342). This discovery is discussed in the context of proton transfer to the lumen.

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.

Structural Role of Carotenoids in Photosynthetic Membranes

1996 ◽  
Vol 51 (11-12) ◽  
pp. 763-771 ◽  
Author(s):  
Andrey A Moskalenko ◽  
Navassard V Karapetyan
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Purple Bacteria ◽  
Reaction Centers ◽  
Structural Components ◽  
Light Harvesting Complexes ◽  
Photosynthetic Membranes

Besides the light-harvesting and protecting role, carotenoids are also instrumental as structural components for the assembly of light-harvesting complexes in purple bacteria and green plants, as well as for the formation of photosystem II complex. Carotenoids stabilize those pigm ent-protein complexes, but have no effect on the form ation of the reaction centers of purple bacteria and photosystem I of plants.

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.

Mechanism of photoinduced electron transfer in photosystem II reaction centers

BIOPHYSICS ◽  
2007 ◽  
Vol 52 (1) ◽  
pp. 40-45 ◽  
Author(s):  
I. B. Klenina ◽  
W. O. Feikema ◽  
P. Gast ◽  
M. G. Zvereva ◽  
I. I. Proskuryakov
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Photoinduced Electron Transfer ◽  
Reaction Centers
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