EPR and 55Mn cw-ENDOR study of an antiferrogmagnetically coupled dinuclear manganese (MnIII MnIV) complex

Zweygart, W.; Bittl, Robert; Wieghardt, Karl; Lubitz, Wolfgang

doi:10.1016/0009-2614(96)00960-8

Cited by 18 publications

(26 citation statements)

References 16 publications

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“…Assuming an octa-hedral coordination structure of the Mn A()a) (III) ion as reported in most synthetic di-µ-oxo bridged dimer complexes, the z-axis of the d z 2 orbital of the Mn A)(a) (III) ion can be thought to be nearly perpendicular to the vector connecting two oxygen atoms in the putative di-µ-oxo bridged dimer unit as shown in Figure 6. This view of the symmetric coordination structure is, furthermore, compatible with the simulation result that both the g-tensor and hyperfine tensor of the Mn A()a) (III) ion are axially symmetric arrangement that has been found in symmetric Mn model complexes (54).…”

Section: R ) |supporting

confidence: 89%

Simulation of S₂-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex

et al. 1998

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High-quality angular-dependent spectra of multiline electron paramagnetic resonance (EPR) signals from the S2-state Mn cluster in a photosynthetic oxygen-evolving complex (OEC) were obtained for partially oriented photosystem (PS) II membranes, and the magnetic structure of the Mn cluster has been studied by simulation analysis. The angular-dependent multiline spectra were simulated by taking into account the anisotropic properties of both hyperfine tensors of intrinsic Mn ions and g-tensor of the cluster in a tetranuclear model. The best-fit parameters for the simulation indicate that (a) the oxidation state of the S2-state Mn cluster is Mn(III, IV, IV, IV), (b) the electronic orbital configuration of the Mn(III) ion is (dpi)3[dz2(sigma))]1, (c) the effective g-tensor of the Mn cluster and the hyperfine tensor of the Mn(III) ion are axially symmetric, and their principal z-axes are nearly collinear each other, and (d) the z-axis of the dz2 orbital of the Mn(III) ion and the normal of the thylakoid membrane are at an angle of 50.1 +/- 1.8 degrees. The results are compatible with those of the oriented XAFS study [Mukerji, I., et al. (1994) Biochemistry 33, 9712-9721], and indicate that the O-O vector of the putative di-mu-oxo bridged Mn(III)-Mn(IV) dimer unit in the Mn cluster tilts by 43-56 degrees with respect to the normal of thylakoid membrane. A model of the arrangement of the di-mu-oxo bridged Mn(III)-Mn(IV) unit with respect to the thylakoid membrane is proposed.

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Section: R ) |supporting

confidence: 89%

Simulation of S₂-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex

et al. 1998

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“…[ [19] has lead to rhombic tensors, in particular g ϭ 2.000, 1.998, 1.984, iso: 1.994. The expression for a rhombic g tensor for Mn(III) has been given in ref [20] …”

Section: Resultsmentioning

confidence: 99%

Synthesis, Structure, Electronic, Redox, and Magnetic Properties of a New Mixed-Valent Mn-Oxo Cluster: [Mn2III,IVO2(N,Nbispicen)2]3+ (N,Nbispicen =N,N-bis(2-pyridylmethyl)-1,2-diaminoethane)

Horner

Charlot

Boussac

et al. 1998

Eur. J. Inorg. Chem.

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“…35 -39 Zweygart et al reported the first cw 55 Mn-ENDOR. 40 The method allows the direct and precise detection of the hfcs of the two metal nuclei and gives information on the nuclear quadrupole interaction.…”

Section: Introductionmentioning

confidence: 99%

High-field EPR investigations of MnIIIMnIV and MnIIMnIII states of dimanganese catalase and related model systems

Teutloff

Schäfer

Sinnecker³

et al. 2005

Magn. Reson. Chem.

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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 55Mn 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.

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EPR and 55Mn cw-ENDOR study of an antiferrogmagnetically coupled dinuclear manganese (MnIII MnIV) complex

Cited by 18 publications

References 16 publications

Simulation of S₂-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex

Simulation of S₂-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex

Synthesis, Structure, Electronic, Redox, and Magnetic Properties of a New Mixed-Valent Mn-Oxo Cluster: [Mn2III,IVO2(N,Nbispicen)2]3+ (N,Nbispicen =N,N-bis(2-pyridylmethyl)-1,2-diaminoethane)

High-field EPR investigations of MnIIIMnIV and MnIIMnIII states of dimanganese catalase and related model systems

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EPR and 55Mn cw-ENDOR study of an antiferrogmagnetically coupled dinuclear manganese (MnIII MnIV) complex

Cited by 18 publications

References 16 publications

Simulation of S2-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex

Simulation of S2-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex

Synthesis, Structure, Electronic, Redox, and Magnetic Properties of a New Mixed-Valent Mn-Oxo Cluster: [Mn2III,IVO2(N,Nbispicen)2]3+ (N,Nbispicen =N,N-bis(2-pyridylmethyl)-1,2-diaminoethane)

High-field EPR investigations of MnIIIMnIV and MnIIMnIII states of dimanganese catalase and related model systems

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Simulation of S₂-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex

Simulation of S₂-State Multiline EPR Signal in Oriented Photosystem II Membranes: Structural Implications for the Manganese Cluster in an Oxygen-Evolving Complex