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Manganese Cluster in Photosynthesis: Where Plants Oxidize Water to Dioxygen.
Mn is well suited for the redox role with accessible oxidation states of II, III, and IV, and possibly V: oxidation states that have all been proposed to explain the mechanisms of the Mn redox enzymes. Expand
Where Water Is Oxidized to Dioxygen: Structure of the Photosynthetic Mn4Ca Cluster
Polarized extended x-ray absorption fine structure measurements on PSII single crystals constrain the Mn4Ca cluster geometry to a set of three similar high-resolution structures, unlike either the 3.0 or 3.5 angstrom–resolution x-rays or other previously proposed models. Expand
X-ray damage to the Mn4Ca complex in single crystals of photosystem II: a case study for metalloprotein crystallography.
This case study shows that a careful evaluation of the structural intactness of the active site(s) by spectroscopic techniques can validate structures derived from crystallography and that it can be a valuable complementary method before structure-function correlations of metalloproteins can be made on the basis of high-resolution x-ray crystal structures. Expand
Structural changes in the Mn4Ca cluster and the mechanism of photosynthetic water splitting
The results show that Ca is not just a spectator atom involved in providing a structural framework, but is actively involved in the mechanism of water oxidation and represents a rare example of a catalytically active Ca cofactor. Expand
Structure‐Based Calculations of the Optical Spectra of the LH2 Bacteriochlorophyll‐Protein Complex from Rhodopseudomonas acidophila
Abstract— The molecular structure of the light‐harvesting complex 2 (LH2) bacteriochlorophyll‐protein antenna complex from the purple non‐sulfur photosynthetic bacterium Rhodopseudomonas acidophila,Expand
EPR detection of a cryogenically photogenerated intermediate in photosynthetic oxygen evolution
Abstract In Photosystem II preparations at low temperature we were able to generate and trap an intermediate state between the S1 and S2 states of the Kok scheme for photosynthetic oxygen evolution.Expand
Reaction kinetics for positive charge accumulation on the water side of choloplast photosystem II
The results of these experiments show that the rate limiting step for the recovery of photoactivity in Photosystem II units is a function of the oxidation state of the S enzyme, indicating that reactions occurring on the reducing side of photosystem II are ratelimiting. Expand
The Dimerization of Chlorophyll a, Chlorophyll b, and Bacteriochlorophyll in Solution1
~ . · . Analyses· of the absorption spectra of three chlorophylls in carbon tetrach1oride solution demonstrate the existence of monomerdimer equilibrium in the concentration range from 10-6 to 10-3Expand
High-resolution Mn EXAFS of the oxygen-evolving complex in photosystem II: structural implications for the Mn4Ca cluster.
High-resolution EXAFS method data is presented that shows three short Mn-Mn distances between 2.7 and 2.8 A and, hence, the presence of three di-mu-oxo-bridged units in the Mn4Ca cluster, imposing clear limitations on the proposed structures based on spectroscopic and diffraction data and provides input for refining such structures. Expand