High-field EPR investigations of MnIIIMnIV and MnIIMnIII states of dimanganese catalase and related model systems
✍ Scribed by Christian Teutloff; Kai-Oliver Schäfer; Sebastian Sinnecker; Vladimir Barynin; Robert Bittl; Karl Wieghardt; Friedhelm Lendzian; Wolfgang Lubitz
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 651 KB
- Volume
- 43
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.1685
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✦ Synopsis
Multi-frequency EPR experiments at 9, 34 and 94 GHz are reported on the antiferromagnetically coupled mixed valence Mn II Mn III complex of manganese catalase and on several dinuclear manganese model systems. They are compared with similar experiments obtained earlier for the Mn III Mn IV states. It is demonstrated how accurate information on the G-and 55 Mn hyperfine tensors can be derived from this approach. Furthermore, the effect of oxidation state, planarity of the manganese-oxygen core and the type of ligands bridging the manganese ions on the magnetic resonance parameters and the related electronic structure is investigated. 'Broken-symmetry' density functional calculations on two Mn III Mn IV complexes, including the superoxidized state of the catalase, are presented. The agreement between calculated and experimental EPR parameters and complex geometries is remarkably good. Implications of these results for the structure and function of the dimanganese catalase are discussed.