Publication Date:
2014-08-16
Description:
The photosynthetic protein complex photosystem II oxidizes water to molecular oxygen at an embedded tetramanganese-calcium cluster. Resolving the geometric and electronic structure of this cluster in its highest metastable catalytic state (designated S3) is a prerequisite for understanding the mechanism of O-O bond formation. Here, multifrequency, multidimensional magnetic resonance spectroscopy reveals that all four manganese ions of the catalyst are structurally and electronically similar immediately before the final oxygen evolution step; they all exhibit a 4+ formal oxidation state and octahedral local geometry. Only one structural model derived from quantum chemical modeling is consistent with all magnetic resonance data; its formation requires the binding of an additional water molecule. O-O bond formation would then proceed by the coupling of two proximal manganese-bound oxygens in the transition state of the cofactor.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cox, Nicholas -- Retegan, Marius -- Neese, Frank -- Pantazis, Dimitrios A -- Boussac, Alain -- Lubitz, Wolfgang -- New York, N.Y. -- Science. 2014 Aug 15;345(6198):804-8. doi: 10.1126/science.1254910. Epub 2014 Aug 14.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mulheim an der Ruhr, Germany. nicholas.cox@cec.mpg.de wolfgang.lubitz@cec.mpg.de. ; Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mulheim an der Ruhr, Germany. ; Institut de Biologie et de Technologies de Saclay, CNRS UMR 8221, Commissariat a l'Energie Atomique (CEA) Saclay, 91191 Gif-sur-Yvette, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25124437" target="_blank"〉PubMed〈/a〉
Keywords:
Bacterial Proteins/*chemistry/metabolism
;
Cyanobacteria/*chemistry/metabolism
;
Electron Spin Resonance Spectroscopy
;
Magnetic Resonance Spectroscopy
;
Manganese/chemistry
;
Models, Chemical
;
Oxidation-Reduction
;
Oxygen/*chemistry/metabolism
;
Photosynthesis
;
Photosystem II Protein Complex/*chemistry/metabolism
;
Physicochemical Processes
;
Water/chemistry
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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