Photosynthetic water oxidation center: spin frustration in distorted cubane MnIVMnIII3 model complexes

1992 ◽  
Vol 114 (7) ◽  
pp. 2455-2471 ◽  
Author(s):  
David N. Hendrickson ◽  
George Christou ◽  
Edward A. Schmitt ◽  
Eduardo Libby ◽  
John S. Bashkin ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Spin Frustration ◽  
Model Complexes ◽  
Photosynthetic Water Oxidation

Preparation and properties of models for the photosynthetic water oxidation center: spin frustration in the manganese [Mn4O2(O2CR)7(pic)2]- anion

1991 ◽  
Vol 30 (18) ◽  
pp. 3486-3495 ◽  
Author(s):  
Eduardo. Libby ◽  
James K. McCusker ◽  
Edward A. Schmitt ◽  
Kirsten. Folting ◽  
David N. Hendrickson ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Spin Frustration ◽  
Photosynthetic Water Oxidation

scholarly journals Using small molecule complexes to elucidate features of photosynthetic water oxidation

2007 ◽  
Vol 363 (1494) ◽  
pp. 1271-1281 ◽  
Author(s):  
Kristof Meelich ◽  
Curtis M Zaleski ◽  
Vincent L Pecoraro
Keyword(s):  
Water Oxidation ◽  
Spectroscopic Characterization ◽  
Structural Features ◽  
Oxygen Evolving Complex ◽  
Model Complexes ◽  
Small Model ◽  
Oxygen Evolving ◽  
Photosynthetic Water Oxidation ◽  
Insight Into

The molecular oxygen produced in photosynthesis is generated via water oxidation at a manganese–calcium cluster called the oxygen-evolving complex (OEC). While studies in biophysics, biochemistry, and structural and molecular biology are well known to provide deeper insight into the structure and workings of this system, it is often less appreciated that biomimetic modelling provides the foundation for interpreting photosynthetic reactions. The synthesis and characterization of small model complexes, which either mimic structural features of the OEC or are capable of providing insight into the mechanism of O 2 evolution, have become a vital contributor to this scientific field. Our group has contributed to these findings in recent years through synthesis of model complexes, spectroscopic characterization of these systems and probing the reactivity in the context of water oxidation. In this article we describe how models have made significant contributions ranging from understanding the structure of the water-oxidation centre (e.g. contributions to defining a tetrameric Mn 3 Ca-cluster with a dangler Mn) to the ability to discriminate between different mechanistic proposals (e.g. showing that the Babcock scheme for water oxidation is unlikely).

scholarly journals Photosynthetic water oxidation

FEBS Letters ◽  
1985 ◽  
Vol 189 (2) ◽  
pp. 258-262 ◽  
Author(s):  
Andrew N. Webber ◽  
Lee Spencer ◽  
Donald T. Sawyer ◽  
Robert L. Heath
Keyword(s):  
Water Oxidation ◽  
Photosynthetic Water Oxidation

scholarly journals Effect of alkaline pH on photosynthetic water oxidation and the association of extrinsic proteins with Photosystem Two

1989 ◽  
Vol 258 (2) ◽  
pp. 357-362 ◽  
Author(s):  
D J Chapman ◽  
J De Felice ◽  
K Davis ◽  
J Barber
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Binding Sites ◽  
Partial Recovery ◽  
Alkaline Ph ◽  
Ph Values ◽  
Extrinsic Proteins ◽  
Reversible Phase ◽  
Photosynthetic Water Oxidation ◽  
Optimal Ph

Incubation of a membrane preparation enriched in Photosystem Two (PSII) at alkaline pH inhibited the water-splitting reactions in two distinct steps. Up to pH 8.5 the inhibition was reversible, whereas at higher alkalinities it was irreversible. It was shown that the reversible phase correlated with loss and rebinding of the 23 kDa extrinsic polypeptide. However, after mild alkaline treatments a partial recovery was possible without the binding of the 23 kDa polypeptide when the assay was at the optimal pH of 6.5 and in a medium containing excess Cl-. The irreversible phase was found to be closely linked with the removal of the 33 kDa extrinsic protein of PSII. Treatments with pH values above 8.5 not only caused the 33 kDa protein to be displaced from the PSII-enriched membranes, but also resulted in an irreversible modification of the binding sites such that the extrinsic 33 kDa protein could not reassociate with PSII when the pH was lowered to 6.5. The results obtained with these more extreme alkaline pH treatments support the notion that the 23 kDa protein cannot bind to PSII unless the 33 kDa protein is already bound. The differential effect of pH on the removal of the 23 kDa and 33 kDa proteins contrasted with the data of Kuwabara & Murata [(1983) Plant Cell Physiol. 24, 741-747], but this discrepancy was accounted for by the use of glycerol in the incubation media.

Concerted hydrogen-atom abstraction in photosynthetic water oxidation

2000 ◽  
Vol 3 (3) ◽  
pp. 236-242 ◽  
Author(s):  
Kristi L Westphal ◽  
Cecilia Tommos ◽  
Robert I Cukier ◽  
Gerald T Babcock
Keyword(s):  
Hydrogen Atom ◽  
Water Oxidation ◽  
Hydrogen Atom Abstraction ◽  
Photosynthetic Water Oxidation
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