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Han Z, Sakai N, Böttger LH, Klinke S, Hauber J, Trautwein AX, Hilgenfeld R. Crystal Structure of the Peroxo-diiron(III) Intermediate of Deoxyhypusine Hydroxylase, an Oxygenase Involved in Hypusination. Structure 2015; 23:882-892. [PMID: 25865244 DOI: 10.1016/j.str.2015.03.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 10/23/2022]
Abstract
Deoxyhypusine hydroxylase (DOHH) is a non-heme diiron enzyme involved in the posttranslational modification of a critical lysine residue of eukaryotic translation initiation factor 5A (eIF-5A) to yield the unusual amino acid residue hypusine. This modification is essential for the role of eIF-5A in translation and in nuclear export of a group of specific mRNAs. The diiron center of human DOHH (hDOHH) forms a peroxo-diiron(III) intermediate (hDOHHperoxo) when its reduced form reacts with O2. hDOHHperoxo has a lifetime exceeding that of the peroxo intermediates of other diiron enzymes by several orders of magnitude. Here we report the 1.7-Å crystal structures of hDOHHperoxo and a complex with glycerol. The structure of hDOHHperoxo reveals the presence of a μ-1,2-peroxo-diiron(III) species at the active site. Augmented by UV/Vis and Mössbauer spectroscopic studies, the crystal structures offer explanations for the extreme longevity of hDOHHperoxo and illustrate how the enzyme specifically recognizes its only substrate, deoxyhypusine-eIF-5A.
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Affiliation(s)
- Zhenggang Han
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Naoki Sakai
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Lars H Böttger
- Institute of Physics, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Sebastián Klinke
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Joachim Hauber
- Heinrich Pette Institute - Leibniz Institute for Experimental Virology, Martinistraße 52, 20251 Hamburg, Germany; German Center for Infection Research (DZIF) c/o Heinrich-Pette-Institute - Leibniz Institute for Experimental Virology, Martinistraße 52, 20251 Hamburg, Germany
| | - Alfred X Trautwein
- Institute of Physics, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Rolf Hilgenfeld
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany; German Center for Infection Research (DZIF) c/o Institute of Biochemistry, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.
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Bill E, Krebs C, Winter M, Gerdan M, Trautwein AX, Flörke U, Haupt HJ, Chaudhuri P. A Triangular Iron(III) Complex Potentially Relevant to Iron(III)-Binding Sites in Ferreascidin. Chemistry 2013; 3:193-201. [PMID: 24022947 DOI: 10.1002/chem.19970030205] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/1996] [Indexed: 11/09/2022]
Abstract
An asymmetric triangular Fe(III) complex has been synthesized by an unusual Fe(II) -promoted activation of salicylaldoxime. Formation of the ligand 2-(bis(salicylideneamino)methyl)phenol in situ is believed to occur through the reductive deoximation of salicylaldoxime by ferrous ions. The trinuclear ferric complex has been characterized on the basis of elemental analysis, IR, variable-temperature magnetic susceptibility, and EPR and Mössbauer spectroscopies. The molecular structure established by X-ray diffraction consists of a trinuclear structure with a [Fe3 (μ3 -O)(μ2 -OPh)](6+) core. Two iron ions are in a distorted octahedral environment having FeN2 O4 coordination spheres, and the five-coordinated third iron ion, with an FeNO4 coordination sphere, is in a trigonal bipyramidal environment. The magnetic susceptibility measurements revealed an St = 5/2 ground state with the antiparallel exchange interactions J = - 34.3 cm(-1) , J' = - 4.7 cm(-1) , and D = - 0.90 cm(-1) . The EPR results are consistent with a ground state of S = 5/2 together with a negative D5/2 value. The Mössbauer isomer shifts together with the quadrupole splitting also provide evidence for the high-spin state of the three ferric sites. Magnetic Mössbauer spectra lead to the conclusion that the internal magnetic fields possibly lie in the plane of the three ferric ions.
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Affiliation(s)
- E Bill
- Max-Planck-Institut für Strahlenchemie P.O. Box 101365, D-45413 Mülheim an der Ruhr (Germany), e-mail:
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Mukherjee A, Bilton PR, Mackay L, Janoschka A, Zhu H, Rea D, Langridge-Smith PRR, Campopiano DJ, Teschner T, Trautwein AX, Schünemann V, Sadler PJ. Ferric ion (hydr)oxo clusters in the “Venus flytrap” cleft of FbpA: Mössbauer, calorimetric and mass spectrometric studies. J Biol Inorg Chem 2012; 17:573-88. [DOI: 10.1007/s00775-012-0878-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 01/24/2012] [Indexed: 11/28/2022]
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Paulsen H, Trautwein AX, Wegner P, Schmidt C, Chumakov AI, Schünemann V. Interpretation of Nuclear Resonant Vibrational Spectra of Rubredoxin Using a Combined Quantum Mechanics and Molecular Mechanics Approach. Chemphyschem 2011; 12:3434-41. [DOI: 10.1002/cphc.201100595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Indexed: 11/06/2022]
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Gruner I, Frädrich C, Böttger LH, Trautwein AX, Jahn D, Härtig E. Aspartate 141 is the fourth ligand of the oxygen-sensing [4Fe-4S]2+ cluster of Bacillus subtilis transcriptional regulator Fnr. J Biol Chem 2010; 286:2017-21. [PMID: 21068385 DOI: 10.1074/jbc.m110.191940] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Bacillus subtilis redox regulator Fnr controls genes of the anaerobic metabolism in response to low oxygen tension. An unusual structure for the oxygen-sensing [4Fe-4S](2+) cluster was detected by a combination of genetic experiments with UV-visible and Mössbauer spectroscopy. Asp-141 was identified as the fourth iron-sulfur cluster ligand besides three Cys residues. Exchange of Asp-141 with Ala abolished functional in vivo complementation of an fnr knock-out strain by the mutagenized fnr gene and in vitro DNA binding of the recombinant regulator FnrD141A. In contrast, substitution of Asp-141 with Cys preserved [4Fe-4S](2+) structure and regulator function.
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Affiliation(s)
- Ines Gruner
- Institute of Microbiology, University Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany
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Böttger LH, Faivre D, Schüler D, Trautwein AX, Matzanke BF. Magnetite formation via membrane-bound ferritin and an iron(II) species at the cytoplasmic membrane and in magnetosomes ofMagnetospirillum gryphiswaldense. ACTA ACUST UNITED AC 2010. [DOI: 10.1088/1742-6596/217/1/012020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Seemann M, Janthawornpong K, Schweizer J, Böttger LH, Janoschka A, Ahrens-Botzong A, Tambou EN, Rotthaus O, Trautwein AX, Rohmer M. Isoprenoid Biosynthesis via the MEP Pathway: In Vivo Mössbauer Spectroscopy Identifies a [4Fe-4S]2+ Center with Unusual Coordination Sphere in the LytB Protein. J Am Chem Soc 2009; 131:13184-5. [DOI: 10.1021/ja9012408] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Myriam Seemann
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Karnjapan Janthawornpong
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Julia Schweizer
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Lars H. Böttger
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Adam Janoschka
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Anne Ahrens-Botzong
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Erasmienne Ngouamegne Tambou
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Olaf Rotthaus
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Alfred X. Trautwein
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Michel Rohmer
- Université de Strasbourg, Institut de Chimie, UMR CNRS UDS 7177, 4 rue Blaise Pascal, 67070 Strasbourg, France, Fachbereich Physik, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, D-67653 Kaiserslautern, Germany, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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Marinoni I, Nonnis S, Monteferrante C, Heathcote P, Härtig E, Böttger LH, Trautwein AX, Negri A, Albertini AM, Tedeschi G. Characterization of L-aspartate oxidase and quinolinate synthase from Bacillus subtilis. FEBS J 2008; 275:5090-107. [PMID: 18959769 DOI: 10.1111/j.1742-4658.2008.06641.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
NAD is an important cofactor and essential molecule in all living organisms. In many eubacteria, including several pathogens, the first two steps in the de novo synthesis of NAD are catalyzed by l-aspartate oxidase (NadB) and quinolinate synthase (NadA). Despite the important role played by these two enzymes in NAD metabolism, many of their biochemical and structural properties are still largely unknown. In the present study, we cloned, overexpressed and characterized NadA and NadB from Bacillus subtilis, one of the best studied bacteria and a model organism for low-GC Gram-positive bacteria. Our data demonstrated that NadA from B. subtilis possesses a [4Fe-4S]2+ cluster, and we also identified the cysteine residues involved in the cluster binding. The [4Fe-4S]2+ cluster is coordinated by three cysteine residues (Cys110, Cys230, and Cys320) that are conserved in all the NadA sequences reported so far, suggesting a new noncanonical binding motif that, on the basis of sequence alignment studies, may be common to other quinolinate synthases from different organisms. Moreover, for the first time, it was shown that the interaction between NadA and NadB is not species-specific between B. subtilis and Escherichia coli.
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Affiliation(s)
- Ilaria Marinoni
- Department of Genetics and Microbiology, University of Pavia, Italy
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Ferrer M, Golyshina OV, Beloqui A, Böttger LH, Andreu JM, Polaina J, De Lacey AL, Trautwein AX, Timmis KN, Golyshin PN. A purple acidophilic di-ferric DNA ligase from Ferroplasma. Proc Natl Acad Sci U S A 2008; 105:8878-83. [PMID: 18577594 PMCID: PMC2438275 DOI: 10.1073/pnas.0800071105] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Indexed: 11/18/2022] Open
Abstract
We describe here an extraordinary purple-colored DNA ligase, LigFa, from the acidophilic ferrous iron-oxidizing archaeon Ferroplasma acidiphilum, a di-ferric enzyme with an extremely low pH activity optimum. Unlike any other DNA ligase studied to date, LigFa contains two Fe(3+)-tyrosinate centers and lacks any requirement for either Mg(2+) or K(+) for activity. DNA ligases from closest phylogenetic and ecophysiological relatives have normal pH optima (6.0-7.5), lack iron, and require Mg(2+)/K(+) for activity. Ferric iron retention is pH-dependent, with release resulting in partial protein unfolding and loss of activity. Reduction of the Fe(3+) to Fe(2+) results in an 80% decrease in DNA substrate binding and an increase in the pH activity optimum to 5.0. DNA binding induces significant conformational change around the iron site(s), suggesting that the ferric irons of LigFa act both as structure organizing and stabilizing elements and as Lewis acids facilitating DNA binding at low pH.
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Affiliation(s)
- Manuel Ferrer
- *Consejo Superior de Investigaciones Científicas, Institute of Catalysis, 28049 Madrid, Spain
| | - Olga V. Golyshina
- Environmental Microbiology Laboratory, Helmholtz Centre for Infection Research (HZI), 38124 Braunschweig, Germany
| | - Ana Beloqui
- *Consejo Superior de Investigaciones Científicas, Institute of Catalysis, 28049 Madrid, Spain
| | - Lars H. Böttger
- Institute of Physics, University of Lübeck, 23538 Lübeck, Germany
| | - José M. Andreu
- Consejo Superior de Investigaciones Científicas, Centro de Investigaciones Biológicas, 28040 Madrid, Spain
| | - Julio Polaina
- Consejo Superior de Investigaciones Científicas, Instituto de Agroquímica y Tecnología de Alimentos, 46980 Valencia, Spain
| | - Antonio L. De Lacey
- *Consejo Superior de Investigaciones Científicas, Institute of Catalysis, 28049 Madrid, Spain
| | | | - Kenneth N. Timmis
- Environmental Microbiology Laboratory, Helmholtz Centre for Infection Research (HZI), 38124 Braunschweig, Germany
- **Institute of Microbiology, Carolo-Wilhelmina Technical University of Braunschweig, 38106 Braunschweig, Germany
| | - Peter N. Golyshin
- Environmental Microbiology Laboratory, Helmholtz Centre for Infection Research (HZI), 38124 Braunschweig, Germany
- **Institute of Microbiology, Carolo-Wilhelmina Technical University of Braunschweig, 38106 Braunschweig, Germany
- School of Biological Sciences, Bangor University, Gwynedd, LL57 2UW, United Kingdom; and
- Centre for Integrated Research in the Rural Environment, Aberystwyth University–Bangor University Partnership (CIRRE), Aberystwyth, Ceredigion SY23 2AX, United Kingdom
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Hersleth HP, Varnier A, Harbitz E, Røhr ÅK, Schmidt PP, Sørlie M, Cederkvist FH, Marchal S, Gorren AC, Mayer B, Uchida T, Schünemann V, Kitagawa T, Trautwein AX, Shimizu T, Lange R, Görbitz CH, Andersson KK. Reactive complexes in myoglobin and nitric oxide synthase. Inorganica Chim Acta 2008. [DOI: 10.1016/j.ica.2007.09.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hersleth HP, Uchida T, Røhr AK, Teschner T, Schünemann V, Kitagawa T, Trautwein AX, Görbitz CH, Andersson KK. Crystallographic and Spectroscopic Studies of Peroxide-derived Myoglobin Compound II and Occurrence of Protonated FeIV–O. J Biol Chem 2007; 282:23372-86. [PMID: 17565988 DOI: 10.1074/jbc.m701948200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
High resolution crystal structures of myoglobin in the pH range 5.2-8.7 have been used as models for the peroxide-derived compound II intermediates in heme peroxidases and oxygenases. The observed Fe-O bond length (1.86-1.90 A) is consistent with that of a single bond. The compound II state of myoglobin in crystals was controlled by single-crystal microspectrophotometry before and after synchrotron data collection. We observe some radiation-induced changes in both compound II (resulting in intermediate H) and in the resting ferric state of myoglobin. These radiation-induced states are quite unstable, and compound II and ferric myoglobin are immediately regenerated through a short heating above the glass transition temperature (<1 s) of the crystals. It is unclear how this influences our compound II structures compared with the unaffected compound II, but some crystallographic data suggest that the influence on the Fe-O bond distance is minimal. Based on our crystallographic and spectroscopic data we suggest that for myoglobin the compound II intermediate consists of an Fe(IV)-O species with a single bond. The presence of Fe(IV) is indicated by a small isomer shift of delta = 0.07 mm/s from Mössbauer spectroscopy. Earlier quantum refinements (crystallographic refinement where the molecular-mechanics potential is replaced by a quantum chemical calculation) and density functional theory calculations suggest that this intermediate H species is protonated.
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Affiliation(s)
- Hans-Petter Hersleth
- Department of Chemistry, University of Oslo, PO Box 1033, Blindern, Oslo N-0315, Norway
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Zoppellaro G, Teschner T, Harbitz E, Schünemann V, Karlsen S, Arciero DM, Ciurli S, Trautwein AX, Hooper AB, Andersson KK. Low-temperature EPR and Mössbauer spectroscopy of two cytochromes with His-Met axial coordination exhibiting HALS signals. Chemphyschem 2007; 7:1258-67. [PMID: 16688708 DOI: 10.1002/cphc.200500693] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
C-type cytochromes with histidine-methionine (His-Met) iron coordination play important roles in electron-transfer reactions and in enzymes. Low-temperature electron paramagnetic resonance (EPR) spectra of low-spin ferric cytochromes c can be divided into two groups, depending on the spread of g values: the normal rhombic ones with small g anisotropy and g(max) below 3.2, and those featuring large g anisotropy with g(max) between 3.3 and 3.8, also denoted as highly axial low spin (HALS) species. Herein we present the detailed magnetic properties of cytochrome c(553) from Bacillus pasteurii (g(max) 3.36) and cytochrome c(552) from Nitrosomonas europaea (g(max) 3.34) over the pH range 6.2 to 8.2. Besides being structurally very similar, cytochrome c(553) shows the presence of a minor rhombic species at pH 6.2 (6 %), whereas cytochrome c(552) has about 25 % rhombic species over pH 7.5. The detailed Mössbauer analysis of cytochrome c(552) confirms the presence of these two low-spin ferric species (HALS and rhombic) together with an 8 % ferrous form with parameters comparable to the horse cytochrome c. Both EPR and Mössbauer data of axial cytochromes c with His-Met iron coordination are consistent with an electronic (d(xy))(2) (d(xz))(2) (d(yz))(1) ground state, which is typical for Type I model hemes.
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Affiliation(s)
- Giorgio Zoppellaro
- Department of Molecular Biosciences, University of Oslo, Box 1041 Blindern, 0316 Oslo, Norway
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Andersson KK, Rohr AK, Strand KR, Wei P, Kolberg M, Barra A, Schunemann V, Trautwein AX, Solomon EI. SPECTROSCOPIC STUDIES OF THE MURINE AND HUMAN P53 INDUCED RIBONUCLEOTIDE REDUCTASE P53R2 PROTEIN, DIFFERENCES IN COOPERATIVE BINDING OF FE(II) WITH THE R2 PROTEIN. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a277-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Aasmund K Rohr
- Molecular BiosciencesUniv in OsloIMBV, PO Box 1041 BlindernOsloNO 0316Norway
| | - Kari R Strand
- Molecular BiosciencesUniv in OsloIMBV, PO Box 1041 BlindernOsloNO 0316Norway
| | - Pin‐Pin Wei
- ChemistryStanford UniversityPalm streetStanfordCA94305
| | - Matthias Kolberg
- Molecular BiosciencesUniv in OsloIMBV, PO Box 1041 BlindernOsloNO 0316Norway
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Garcia Y, Paulsen H, Schünemann V, Trautwein AX, Wolny JA. Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d4systems [MnIII(pyrol)3tren] and [CrII(depe)2I2]. Phys Chem Chem Phys 2007; 9:1194-201. [PMID: 17325765 DOI: 10.1039/b616258d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The vibrational contribution to DeltaS of the low-spin ((3)T(1)) to high-spin ((5)E) spin transition in two 3d(4) octahedral systems [Mn(III)(pyrol)(3)tren] and [Cr(depe)(2)I(2)] have been estimated by means of DFT calculations (B3LYP/CEP-31G) of the vibrational normal-modes frequencies. The obtained value at the transition temperature for the Mn(iii) complex is DeltaS(vib)(44 K) = 6.3 J K(-1) mol(-1), which is comparable with the proposed Jahn-Teller contribution of R ln3 = 9.1 J K(-1) mol(-1) and which is approximately half of the experimentally determined 13.8 J K(-1) mol(-1). The corresponding value for the Cr(ii) complex is DeltaS(vib)(171.45 K) = 46.5 J K(-1) mol(-1), as compared to the experimental value of 39.45 J K(-1) mol(-1). The analysis of the vibrational normal modes reveals that for the d(4) systems under study, contrary to Fe(ii) d(6) systems, not all metal-ligand stretching vibrations make a contribution. For the Mn(iii) complex, the only vibration that contributes to DeltaS(vib) involve the nitrogens occupying the Jahn-Teller axis, while in the case of Cr(ii) the contributing vibrations involve the Cr-I bonds. Low-frequency modes due to ring vibrations, metal-ligand bending and movement of the molecule as a whole also contribute to the vibrational entropy associated with the spin transition.
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Affiliation(s)
- Yann Garcia
- Unité de Chimie des Matériaux Inorganiques et Organiques, Département de Chimie, Faculté des Sciences, Université Catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve, Belgium
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Lemercier G, Bréfuel N, Shova S, Wolny JA, Dahan F, Verelst M, Paulsen H, Trautwein AX, Tuchagues JP. A Range of Spin-Crossover TemperatureT1/2>300 K Results from Out-of-Sphere Anion Exchange in a Series of Ferrous Materials Based on the 4-(4-Imidazolylmethyl)-2-(2-imidazolylmethyl)imidazole (trim) Ligand, [Fe(trim)2]X2 (X=F, Cl, Br, I): Comparison of Experimental Results with Those Derived from Density Functional Theory Calculations. Chemistry 2006; 12:7421-32. [PMID: 16874821 DOI: 10.1002/chem.200501249] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The synthesis and characterization of [FeII(trim)2]Cl2 (2), [FeII(trim)2]Br2MeOH (3), and [FeII(trim)2]I2MeOH (4), including the X-ray crystal structure determinations of 2 (50 and 293 K) and 4 (293 K), have been performed and their properties have been examined. In agreement with the magnetic susceptibility results, the Mössbauer data show the presence of high-spin (HS) to low-spin (LS) crossover with a range of T1/2 larger than 300 K (from approximately 20 K for [FeII(trim)2]F2 (1) to approximately 380 K for 4). All complexes in this series include the same [Fe(trim)2]2+ complex cation: the ligand field comprises a constant contribution from the trim ligands and a variable one originating from the out-of-sphere anions, which is transmitted to the metal center by the connecting imidazole rings and hydrogen bonds. The impressive variation in the intrinsic characteristics of the spin-crossover (SCO) phenomenon in this series is then interpreted as an inductive effect of the anions transmitted to the nitrogen donors through the hydrogen bonds. Based on this qualitative analysis, an increased inductive effect of the out-of-sphere anion corresponds to a decreased SCO temperature T1/2, in agreement with the experimental results. Electronic structure calculations with periodic boundary conditions have been performed that show the importance of intermolecular effects in tuning the ligand field, and thus in determining the transition temperature. Starting with the geometries obtained from the X-ray studies, the [FeII(trim)2]X2 complex molecules 1-4 have been investigated both for the single molecules and the crystal lattices with the local density approximation of density functional theory. The bulk geometries of the complex cations deduced from the X-ray studies and those calculated are in fair agreement for both approaches. However, the trend observed for the transition temperatures of 1-4 disagrees with the trend for the spin-state splittings ES (difference EHS-ELS between the energy of the HS and LS isomers) calculated for the isolated molecules, whereas it agrees with the trend for ES calculated with periodic boundary conditions. The latter calculations predict the strongest stabilization of the HS state for the fluoride complex, which actually is essentially HS above T=50 K, while the most pronounced stabilization of the LS state is predicted for 4, in line with the experimental results.
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Affiliation(s)
- Gilles Lemercier
- Laboratoire de Chimie de Coordination du CNRS, UPR 8241 205 route de Narbonne, 31077 Toulouse Cédex, France
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16
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Prakash R, Saalfrank RW, Maid H, Scheurer A, Heinemann FW, Trautwein AX, Böttger LH. Synthese und Redoxeigenschaften gemischtvalenter achtkerniger Eisendefekthexacubane und eines (CaCl)-überdachten raumzentrierten Eisen(III)-Sechsflächners. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200601478] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Prakash R, Saalfrank RW, Maid H, Scheurer A, Heinemann FW, Trautwein AX, Böttger LH. Synthesis and Redox Properties of Mixed-Valent Octanuclear Iron Defective Hexacubanes and a (CaCl)-Capped Body-Centered Six-Sided Iron(III) Polyhedron. Angew Chem Int Ed Engl 2006; 45:5885-9. [PMID: 16874837 DOI: 10.1002/anie.200601478] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Raju Prakash
- Institut für Organische Chemie, Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
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18
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Böttger LH, Chumakov AI, Matthias Grunert C, Gütlich P, Kusz J, Paulsen H, Ponkratz U, Rusanov V, Trautwein AX, Wolny JA. Spin- and phase transition in the spin crossover complex [Fe(ptz)6](BF4)2 studied by nuclear inelastic scattering of synchrotron radiation and by DFT calculations. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Reents H, Gruner I, Harmening U, Böttger LH, Layer G, Heathcote P, Trautwein AX, Jahn D, Härtig E. Bacillus subtilis Fnr senses oxygen via a [4Fe-4S] cluster coordinated by three cysteine residues without change in the oligomeric state. Mol Microbiol 2006; 60:1432-45. [PMID: 16796679 DOI: 10.1111/j.1365-2958.2006.05198.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The oxygen regulator Fnr is part of the regulatory cascade in Bacillus subtilis for the adaptation to anaerobic growth conditions. In vivo complementation experiments revealed the essential role of only three cysteine residues (C227, C230, C235) at the C-terminus of B. subtilis Fnr for the transcriptional activation of the nitrate reductase operon (narGHJI) and nitrite extrusion protein gene (narK) promoters. UV/VIS, electron paramagnetic spin resonance (EPR) and Mössbauer spectroscopy experiments in combination with iron and sulphide content determinations using anaerobically purified recombinant B. subtilis Fnr identified the role of these three cysteine residues in the formation of one [4Fe-4S]2+ cluster per Fnr molecule. The obtained Mössbauer parameters are supportive for a [4Fe-4S]2+ cluster with three cysteine ligated iron sites and one non-cysteine ligated iron site. Gel filtration experiments revealed a stable dimeric structure for B. subtilis Fnr which is independent of the presence of the [4Fe-4S]2+ cluster. Gel mobility shift and in vitro transcription assays demonstrated the essential role of an intact [4Fe-4S]2+ cluster for promoter binding and transcriptional activation. An amino acid exchange introduced in the proposed alphaD-helix of B. subtilis Fnr (G149S) abolished its in vivo and in vitro activities indicating its importance for intramolecular signal transduction. The clear differences in the localization and coordination of the [4Fe-4S] cluster and in the organization of the oligomeric state between Escherichia coli and B. subtilis Fnr indicate differences in their mode of action.
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Affiliation(s)
- Heike Reents
- Institute of Microbiology, Technical University of Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany
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20
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Teschner T, Yatsunyk L, Schünemann V, Paulsen H, Winkler H, Hu C, Scheidt WR, Walker FA, Trautwein AX. Models of the membrane-bound cytochromes: mössbauer spectra of crystalline low-spin ferriheme complexes having axial ligand plane dihedral angles ranging from 0 degree to 90 degrees. J Am Chem Soc 2006; 128:1379-89. [PMID: 16433558 PMCID: PMC1525297 DOI: 10.1021/ja056343k] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Crystalline samples of four low-spin Fe(III) octaalkyltetraphenylporphyrinate and two low-spin Fe(III) tetramesitylporphyrinate complexes, all of which are models of the bis-histidine-coordinated cytochromes of mitochondrial complexes II, III, and IV and chloroplast complex b(6)f, and whose molecular structures and EPR spectra have been reported previously, have been investigated in detail by Mössbauer spectroscopy. The six complexes and the dihedral angles between axial ligand planes of each are [(TMP)Fe(1-MeIm)(2)]ClO(4) (0 degree), paral-[(OMTPP)Fe(1-MeIm)(2)]Cl (19.5 degrees), paral-[(TMP)Fe(5-MeHIm)(2)]ClO(4) (26 degrees, 30 degrees for two molecules in the unit cell whose EPR spectra overlap), [(OETPP)Fe(4-Me(2)NPy)(2)]Cl (70 degrees), perp-[(OETPP)Fe(1-MeIm)(2)]Cl (73 degrees), and perp-[(OMTPP)Fe(1-MeIm)(2)]Cl (90 degrees). Of these, the first three have been shown to exhibit normal rhombic EPR spectra, each with three clearly resolved g-values, while the last three have been shown to exhibit "large g(max)" EPR spectra at 4.2 K. It is found that the hyperfine coupling constants of the complexes are consistent with those reported previously for low-spin ferriheme systems, with the largest-magnitude hyperfine coupling constant, A(zz), being considerably smaller for the "parallel" complexes (400-540 kG) than for the strictly perpendicular complex (902 kG), A(xx) being negative for all six complexes, and A(zz) and A(xx) being of similar magnitude for the "parallel" complexes (for example, for [(TMP)Fe(1-MeIm)(2)]Cl, A(zz) = 400 kG, A(xx) = -400 kG). In all cases, A(yy) is small but difficult to estimate with accuracy. With results for six structurally characterized model systems, we find for the first time qualitative correlations of g(zz), A(zz), and DeltaE(Q) with axial ligand plane dihedral angle Deltavarphi.
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Saalfrank RW, Prakash R, Maid H, Hampel F, Heinemann FW, Trautwein AX, Böttger LH. Synthesis and Characterization of Metal-Centered, Six-Membered, Mixed-Valent, Heterometallic Wheels of Iron, Manganese, and Indium. Chemistry 2006; 12:2428-33. [PMID: 16470618 DOI: 10.1002/chem.200501497] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Heptanuclear metal-centered, six-membered, mixed-valent, heterometallic wheels 1-3 of iron, manganese, and indium were prepared in a one-pot reaction from N-benzyldiethanolamine (H2L(1)), cesium carbonate, [PPh4]2[MnCl4], and FeCl3 or InCl3. All three complexes were characterized by the combination of elemental analysis, FAB mass spectroscopy, X-ray diffraction and cyclic voltammetry and in the case of 1 additionally by Mössbauer spectroscopy. In 1, four Mn(II) ions in the periphery are arranged in pairs alternating with one Fe(III) ion each, with an Fe(III) ion located in the center. In 2, three Mn(II) ions alternate with three In(III) ions, whereas in 3, four In(III) ions are arranged in pairs and alternate with one Mn(II) ion each. In 2 and 3 an Mn(II) ion is encapsulated in the center.
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Affiliation(s)
- Rolf W Saalfrank
- Institut für Organische Chemie der Universität Erlangen-Nürnberg, Henkestrasse 42, 91054 Erlangen, Germany.
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22
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Saalfrank RW, Scheurer A, Bernt I, Heinemann FW, Postnikov AV, Schünemann V, Trautwein AX, Alam MS, Rupp H, Müller P. The {FeIII[FeIII(L1)2]3} star-type single-molecule magnet. Dalton Trans 2006:2865-74. [PMID: 16751895 DOI: 10.1039/b515980f] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Star-shaped complex [Fe(III)[Fe(III)(L1)2]3] (3) was synthesized starting from N-methyldiethanolamine H2L1 (1) and ferric chloride in the presence of sodium hydride. For 3, two different high-spin iron(III) ion sites were confirmed by Mössbauer spectroscopy at 77 K. Single-crystal X-ray structure determination revealed that 3 crystallizes with four molecules of chloroform, but, with only three molecules of dichloromethane. The unit cell of 3.4CHCl3 contains the enantiomers (delta)-[(S,S)(R,R)(R,R)] and (lambda)-[(R,R)(S,S)(S,S)], whereas in case of 3.3CH2Cl2 four independent molecules, forming pairs of the enantiomers [lambda-(R,R)(R,R)(R,R)]-3 and [lambda-(S,S)(S,S)(S,S)]-3, were observed in the unit cell. According to SQUID measurements, the antiferromagnetic intramolecular coupling of the iron(III) ions in 3 results in a S = 10/2 ground state multiplet. The anisotropy is of the easy-axis type. EPR measurements enabled an accurate determination of the ligand-field splitting parameters. The ferric star 3 is a single-molecule magnet (SMM) and shows hysteretic magnetization characteristics below a blocking temperature of about 1.2 K. However, weak intermolecular couplings, mediated in a chainlike fashion via solvent molecules, have a strong influence on the magnetic properties. Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) were used to determine the structural and electronic properties of star-type tetranuclear iron(III) complex 3. The molecules were deposited onto highly ordered pyrolytic graphite (HOPG). Small, regular molecule clusters, two-dimensional monolayers as well as separated single molecules were observed. In our STS measurements we found a rather large contrast at the expected locations of the metal centers of the molecules. This direct addressing of the metal centers was confirmed by DFT calculations.
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Affiliation(s)
- Rolf W Saalfrank
- Institut für Organische Chemie, Universität Erlangen-Nürnberg, Henkestr. 42, 91054, Erlangen, Germany.
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23
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Ronayne KL, Paulsen H, Höfer A, Dennis AC, Wolny JA, Chumakov AI, Schünemann V, Winkler H, Spiering H, Bousseksou A, Gütlich P, Trautwein AX, McGarvey JJ. Vibrational spectrum of the spin crossover complex [Fe(phen)2(NCS)2] studied by IR and Raman spectroscopy, nuclear inelastic scattering and DFT calculations. Phys Chem Chem Phys 2006; 8:4685-93. [PMID: 17047767 DOI: 10.1039/b610634j] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The vibrational modes of the low-spin and high-spin isomers of the spin crossover complex [Fe(phen)(2)(NCS)(2)] (phen = 1,10-phenanthroline) have been measured by IR and Raman spectroscopy and by nuclear inelastic scattering. The vibrational frequencies and normal modes and the IR and Raman intensities have been calculated by density functional methods. The vibrational entropy difference between the two isomers, DeltaS(vib), which is--together with the electronic entropy difference DeltaS(el)--the driving force for the spin-transition, has been determined from the measured and from the calculated frequencies. The calculated difference (DeltaS(vib) = 57-70 J mol(-1) K(-1), depending on the method) is in qualitative agreement with experimental values (20-36 J mol(-1) K(-1)). Only the low energy vibrational modes (20% of the 147 modes of the free molecule) contribute to the entropy difference and about three quarters of the vibrational entropy difference are due to the 15 modes of the central FeN(6) octahedron.
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Affiliation(s)
- Kate L Ronayne
- School of Chemistry and Chemical Engineering, Queen's University Belfast, BT9 5AG, Belfast, Northern Ireland
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24
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Jung C, Lendzian F, Schünemann V, Richter M, Böttger LH, Trautwein AX, Contzen J, Galander M, Ghosh DK, Barra AL. Multi-frequency EPR and Mössbauer spectroscopic studies on freeze-quenched reaction intermediates of nitric oxide synthase. Magn Reson Chem 2005; 43 Spec no.:S84-95. [PMID: 16235218 DOI: 10.1002/mrc.1694] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
It is believed by analogy to chloroperoxidase (CPO) from Caldariomyces fumago that the electronic structure of the intermediate iron-oxo species in the catalytic cycle of nitric oxide synthase (NOS) corresponds to an iron(IV) porphyrin-pi -cation radical. Such species can also be produced by the reaction of ferric NOS with external oxidants within the shunt pathway. We present multi-frequency EPR (9.6, 94, 285 GHz) and Mössbauer spectroscopic studies on freeze-quenched intermediates of the oxygenase domain of nitric oxide synthase which has reacted with peroxy acetic acid within 8-200 ms. The intermediates of the oxygenase domain of both the cytokine inducible NOS (iNOSox) and the neuronal NOS (nNOSox) show an organic radical signal in the 9.6-GHz spectrum overlapping with the spectrum of an unknown species with g-values of 2.24, 2.23 and 1.96. Using 94- and 285-GHz EPR the organic radical signal is assigned to a tyrosine radical on the basis of g-values (i.e. Tyr*562 in nNOSox and Tyr*341 in iNOSox). Mössbauer spectroscopy of (57)Fe-labeled unreacted nNOSox shows a ferric low-spin heme-iron (delta = 0.38 mms(-1), deltaE(Q) = 2.58 mms(-1)). The reaction of nNOSox with peroxy acetic acid for 8 ms leads to the disappearance of the magnetic background characteristic for native nNOSox and a new species with delta = 0.27 mms(-1) and deltaE(Q) = 2.41 mms(-1) is detected at 4.2 K which does not resemble the parameters typical for a Fe(IV) center. It is proposed that this intermediate species corresponds to a ferric low-spin species which magnetically couples to an amino acid radical (presumably Trp*409).
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Affiliation(s)
- C Jung
- Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
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25
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Saalfrank RW, Scheurer A, Reimann U, Hampel F, Trieflinger C, Büschel M, Daub J, Trautwein AX, Schünemann V, Coropceanu V. Homo-/Heterotrinuclear Mixed-Valent Oxo-Centered Iron/Nickel Clusters—Mössbauer Studies on Internal Electron-Exchange Processes. Chemistry 2005; 11:5843-8. [PMID: 16041808 DOI: 10.1002/chem.200500097] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In a one-pot reaction of N-(5-methylthiazole-2-yl)-thiazole-2-carboxamide HL2 (3) with iron(II) acetate in air, the homotrinuclear heteroleptic mixed-valent oxo-centered iron cluster [Fe(II)Fe(III)O(L2)3(OAc)3] (4) was formed. Exchange of iron(II) in 4 by nickel(II) afforded the heteronuclear cluster [Ni(II)Fe(III)O(L2)3(OAc)3] (6). To obtain crystals suitable for X-ray structure analyses, in 4 and 6, the OAc- co-ligands were exchanged by OBz- ligands to give [Fe(II)Fe2(III)O(L2)3(OBz)3] (5) and [Ni(II)Fe(III)O(L2)3(OBz)3] (7). The complexes 5 and 7 are isostructural and made up of three ditopic, tridentate ligands (L2)- and three bridging benzoate co-ligands, which fix the three metal ions in the corners of a triangle with an mu3-O2- ion in the center. The mixed-valent character of 4-7, their intramolecular electron-exchange processes, and their redox properties were studied by variable-temperature Mössbauer spectroscopy and cyclic voltammetry.
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Affiliation(s)
- Rolf W Saalfrank
- Institut für Organische Chemie der Universität Erlangen-Nürnberg, Henkestrasse 42, 91054 Erlangen, Germany.
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26
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Layer G, Grage K, Teschner T, Schünemann V, Breckau D, Masoumi A, Jahn M, Heathcote P, Trautwein AX, Jahn D. Radical S-Adenosylmethionine Enzyme Coproporphyrinogen III Oxidase HemN. J Biol Chem 2005; 280:29038-46. [PMID: 15967800 DOI: 10.1074/jbc.m501275200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The S-adenosylmethionine (AdoMet) radical enzyme oxygen-independent coproporphyrinogen III oxidase HemN catalyzes the oxidative decarboxylation of coproporphyrinogen III to protoporphyrinogen IX during bacterial heme biosynthesis. The recently solved crystal structure of Escherichia coli HemN revealed the presence of an unusually coordinated iron-sulfur cluster and two molecules of AdoMet. EPR spectroscopy of the reduced iron-sulfur center in anaerobically purified HemN in the absence of AdoMet has revealed a [4Fe-4S](1+) cluster in two slightly different conformations. Mössbauer spectroscopy of anaerobically purified HemN has identified a predominantly [4Fe-4S](2+) cluster in which only three iron atoms were coordinated by cysteine residues (isomer shift of delta = 0.43 (1) mm/s). The fourth non-cysteine-ligated iron exhibited a delta = 0.57 (3) mm/s, which shifted to a delta = 0.68 (3) mm/s upon addition of AdoMet. Substrate binding by HemN did not alter AdoMet coordination to the cluster. Multiple rounds of AdoMet cleavage with the formation of the reaction product methionine indicated AdoMet consumption during catalysis and identified AdoMet as a co-substrate for HemN catalysis. AdoMet cleavage was found to be dependent on the presence of the substrate coproporphyrinogen III. Two molecules of AdoMet were cleaved during one catalytic cycle for the formation of one molecule of protoporphyrinogen IX. Finally, the binding site for the unusual second, non iron-sulfur cluster coordinating AdoMet molecule (AdoMet2) was targeted using site-directed mutagenesis. All AdoMet2 binding site mutants still contained an iron-sulfur cluster and most still exhibited AdoMet cleavage, albeit reduced compared with the wild-type enzyme. However, all mutants lost their overall catalytic ability indicating a functional role for AdoMet2 in HemN catalysis. The reported significant correlation of structural and functional biophysical and biochemical data identifies HemN as a useful model system for the elucidation of general AdoMet radical enzyme features.
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Affiliation(s)
- Gunhild Layer
- Institut für Mikrobiologie, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
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Paulsen H, Wolny JA, Trautwein AX. Chemical Bonds and Spin State Splittings in Spin Crossover Complexes. A DFT and QTAIM Analysis. Monatshefte für Chemie 2005. [DOI: 10.1007/s00706-005-0311-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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28
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Saalfrank RW, Scheurer A, Pokorny K, Maid H, Reimann U, Hampel F, Heinemann FW, Schünemann V, Trautwein AX. Trinuclear Oxo-Centered Iron and Iron/Nickel Clusters - Ligand-Controlled Homo/Hetero Valency. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200400821] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Seemann M, Wegner P, Schünemann V, Bui BTS, Wolff M, Marquet A, Trautwein AX, Rohmer M. Isoprenoid biosynthesis in chloroplasts via the methylerythritol phosphate pathway: the (E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (GcpE) from Arabidopsis thaliana is a [4Fe-4S] protein. J Biol Inorg Chem 2005; 10:131-7. [PMID: 15650872 DOI: 10.1007/s00775-004-0619-z] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 12/02/2004] [Indexed: 11/25/2022]
Abstract
The mevalonate-independent methylerythritol phosphate pathway is widespread in bacteria. It is also present in the chloroplasts of all phototrophic organisms. Whereas the first steps, are rather well known, GcpE and LytB, the enzymes catalyzing the last two steps have been much less investigated. 2-C-Methyl-D-erythritol 2,4-cyclodiphosphate is transformed by GcpE into 4-hydroxy-3-methylbut-2-enyl diphosphate, which is converted by LytB into isopentenyl diphosphate or dimethylallyl diphosphate. Only the bacterial GcpE and LytB enzymes have been investigated to some extent, but nothing is known about the corresponding plant enzymes. In this contribution, the prosthetic group of GcpE from the plant Arabidopsis thaliana and the bacterium Escherichia coli has been fully characterized by Mossbauer spectroscopy after reconstitution with (57)FeCl(3), Na(2)S and dithiothreitol. It corresponds to a [4Fe-4S] cluster, suggesting that both plant and bacterial enzymes catalyze the reduction of 2-C-methyl-D-erythritol 2,4-cyclodiphosphate into (E)-4-hydroxy-3-methylbut-2-enyl diphosphate via two consecutive one-electron transfers. In contrast to the bacterial enzyme, which utilizes NADPH/flavodoxin/flavodoxin reductase as a reducing shuttle system, the plant enzyme could not use this reduction system. Enzymatic activity was only detected in the presence of the 5-deazaflavin semiquinone radical.
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Affiliation(s)
- Myriam Seemann
- Institut Le Bel, UMR 7123 CNRS, Université Louis Pasteur, Strasbourg, France
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30
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Jung C, Schünemann V, Lendzian F, Trautwein AX, Contzen J, Galander M, Böttger LH, Richter M, Barra AL. Spectroscopic characterization of the iron-oxo intermediate in cytochrome P450. Biol Chem 2005; 386:1043-53. [PMID: 16218876 DOI: 10.1515/bc.2005.120] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
From analogy to chloroperoxidase from Caldariomyces fumago, it is believed that the electronic structure of the intermediate iron-oxo species in the catalytic cycle of cytochrome P450 corresponds to an iron(IV) porphyrin-pi-cation radical (compound I). However, our recent studies on P450cam revealed that after 8 ms a tyrosine radical and iron(IV) were formed in the reaction of ferric P450 with external oxidants in the shunt pathway. The present study on the heme domain of P450BM3 (P450BMP) shows a similar result. In addition to a tyrosine radical, a contribution from a tryptophan radical was found in the electron paramagnetic resonance (EPR) spectra of P450BMP. Here we present comparative multi-frequency EPR (9.6, 94 and 285 GHz) and Mössbauer spectroscopic studies on freeze-quenched intermediates produced using peroxy acetic acid as oxidant for both P450 cytochromes. After 8 ms in both systems, amino acid radicals occurred instead of the proposed iron(IV) porphyrin-pi-cation radical, which may be transiently formed on a much faster time scale. These findings are discussed with respect to other heme thiolate proteins. Our studies demonstrate that intramolecular electron transfer from aromatic amino acids is a common feature in these enzymes. The electron transfer quenches the presumably transiently formed porphyrin-pi-cation radical, which makes it extremely difficult to trap compound I.
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Affiliation(s)
- Christiane Jung
- Max-Delbrück-Center for Molecular Medicine, D-13125 Berlin, Germany.
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Brady C, Callaghan PL, Ciunik Z, Coates CG, Døssing A, Hazell A, McGarvey JJ, Schenker S, Toftlund H, Trautwein AX, Winkler H, Wolny JA. Molecular Structure and Vibrational Spectra of Spin-Crossover Complexes in Solution and Colloidal Media: Resonance Raman and Time-Resolved Resonance Raman Studies. Inorg Chem 2004; 43:4289-99. [PMID: 15236542 DOI: 10.1021/ic049809t] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The spin-crossover system [Fe(btpa)](PF(6))(2) (btpa = N,N,N',N'-tetrakis(2-pyridylmethyl)-6,6'-bis(aminomethyl)-2,2'-bipyridine) and the predominantly low-spin species [Fe(b(bdpa))](PF(6))(2) ((b(bdpa) = N,N'-bis(benzyl)-N,N'-bis(2-pyridylmethyl)-6,6'-bis(aminomethyl)-2,2'-bipyridine) have been characterized by means of X-ray diffraction. The unit cell of [Fe(btpa)](PF(6))(2) contains two crystallographically independent molecules revealing octahedral low-spin and quasi-seven-coordinated high-spin structures. The unit cell of [Fe(b(bdpa))](PF(6))(2) contains two crystallographically independent molecules one of which corresponds to a low-spin structure, while the other reveals a disordering. On the basis of magnetic susceptibility and Mössbauer measurements, it has been proposed that this disorder involves low-spin and high-spin six-coordinated molecules. The structures of [Zn(btpa)](PF(6))(2) and [Ru(btpa)](PF(6))(2) have been determined also. Pulsed laser photoperturbation, coupled here with time-resolved resonance Raman spectroscopy (TR(3)), has been used to investigate, for the first time by this technique, the relaxation dynamics in solution on nanosecond and picosecond time scales of low-spin, LS ((1)A) --> high-spin, HS ((5)T) electronic spin-state crossover in these Fe(II) complexes. For the nanosecond experiments, use of a probe wavelength at 321 nm, falling within the pi-pi transition of the polypyridyl backbone of the ligands, enabled the investigation of vibrational modes of both LS and HS isomers, through coupling to spin-state-dependent angle changes of the backbone. Supplementary investigations of the spin-crossover (SCO) equilibrium in homogeneous solution and in colloidal media assisted the assignment of prominent features in the Raman spectra of the LS and HS isomers. The relaxation data from the nanosecond studies confirm and extend earlier spectrophotometric findings, (Schenker, S.; Stein, P. C.; Wolny, J. A.; Brady, C.; McGarvey, J. J.; Toftlund, H.; Hauser, A. Inorg. Chem. 2001, 40, 134), pointing to biphasic spin-state relaxation in the case of [Fe(btpa)](PF(6))(2) but monophasic in the case of [Fe(b(bdpa))](PF(6))(2). The picosecond results suggest an early process complete in 20 ps or less, which is common to both complexes and possibly includes vibrational relaxation in the initially formed (5)T(2) state.
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Affiliation(s)
- Clare Brady
- School of Chemistry, Queens University Belfast, Stranmillis Road, Belfast BT9 5AG, Northern Ireland
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Abstract
FhuF is a cytoplasmic 2Fe-2S protein of Escherichia coli loosely associated with the cytoplasmic membrane. E. coli fhuF mutants showed reduced growth on plates with ferrioxamine B as the sole iron source, although siderophore uptake was not defective in transport experiments. Removal of iron from coprogen, ferrichrome, and ferrioxamine B was significantly lower in fhuF mutants compared to the corresponding parental strains, which suggested that FhuF is involved in iron removal from these hydroxamate-type siderophores. A redox potential E(1/2) of -310 +/- 25 mV relative to the normal hydrogen electrode was determined for FhuF by EPR redox titration; this redox potential is sufficient to reduce the siderophores coprogen and ferrichrome. Mössbauer spectra revealed that FhuF in its [Fe(2+)-Fe(3+)] state is also capable of direct reduction of ferrioxamine B-bound ferric iron, thus proving its reductase function. This is the first report on a bacterial siderophore-iron reductase which in vivo seems to be specific for a certain group of hydroxamates.
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Affiliation(s)
- Berthold F Matzanke
- Isotopenlabor TNF, Institut für Biochemie, and Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
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Ochsenbein P, Mandon D, Fischer J, Weiss R, Austin R, Jayaraj K, Gold A, Terner J, Bill E, Müther M, Trautwein AX. Oxoferryl π-Cation Radical of β-Pyrrole Octachlorinatedmeso-Tetramesitylporphyrin: Electronic and Structural Properties. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/anie.199314371] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Schünemann V, Lendzian F, Jung C, Contzen J, Barra AL, Sligar SG, Trautwein AX. Tyrosine radical formation in the reaction of wild type and mutant cytochrome P450cam with peroxy acids: a multifrequency EPR study of intermediates on the millisecond time scale. J Biol Chem 2003; 279:10919-30. [PMID: 14688245 DOI: 10.1074/jbc.m307884200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We report a multifrequency (9.6-, 94-, 190-, and 285-GHz) EPR study of a freeze-quenched intermediate obtained from reaction of substrate-free cytochrome P450cam (CYP101) and its Y96F and Y96F/Y75F mutants with peroxy acids. It is generally assumed that in such a shunt reaction an intermediate [Fe(IV)=O, porphyrin-pi-cation radical] is formed, which should be identical to the species in the natural reaction cycle. However, for the wild type as well as for the mutant proteins, a porphyrin-pi-cation radical is not detectable within 8 ms. Instead, EPR signals corresponding to tyrosine radicals are obtained for the wild type and the Y96F mutant. Replacement of both Tyr-96 and Tyr-75 by phenylalanine leads to the disappearance of the tyrosine EPR signals. EPR studies at 285 GHz on freeze-quenched wild type and Y96F samples reveal g tensor components for the radical (stretched g(x) values from 2.0078 to 2.0064, g(y) = 2.0043, and g(z) = 2.0022), which are fingerprints for tyrosine radicals in a heterogeneous polar environment. The measurements at 94 GHz using a fundamental mode microwave resonator setup confirm the 285-GHz study. From the simulation of the hyperfine structure in the 94-GHz EPR spectra the signals have been assigned to Tyr-96 in the wild type and to Tyr-75 in the Y96F mutant. We suggest that a transiently formed Fe(IV)=O porphyrin-pi-cation radical intermediate in P450cam is reduced by intramolecular electron transfer from these tyrosines within 8 ms.
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Benda R, Schünemann V, Trautwein AX, Cai S, Reddy Polam J, Watson CT, Shokhireva TK, Walker FA. Models of the bis-histidine-coordinated ferricytochromes: Mössbauer and EPR spectroscopic studies of low-spin iron(III) tetrapyrroles of various electronic ground states and axial ligand orientations. J Biol Inorg Chem 2003; 8:787-801. [PMID: 12898323 DOI: 10.1007/s00775-003-0472-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2002] [Accepted: 05/19/2003] [Indexed: 10/26/2022]
Abstract
The EPR and magnetic Mössbauer spectra of a series of axial ligand complexes of tetrakis(2,6-dimethoxyphenyl)porphyrinatoiron(III), [(2,6-(OMe)(2))(4)TPPFeL(2)](+), where L= N-methylimidazole, 2-methylimidazole, or 4-(dimethylamino)pyridine, of one axial ligand complex of tetraphenylporphyrin, the bis(4-cyanopyridine) complex [TPPFe(4-CNPy)(2)](+), and of one axial ligand complex of tetraphenylchlorin, [TPCFe(ImH)(2)](+), where ImH=imidazole, have been investigated and compared to those of low-spin Fe(III) porphyrinates and ferriheme proteins reported in the literature. On the basis of this and previous complementary spectroscopic investigations, three types of complexes have been identified: those having (d(xy))(2)(d(xz),d(yz))(3) electronic ground states with axial ligands aligned in perpendicular planes (Type I), those having (d(xy))(2)(d(xz),d(yz))(3) electronic ground states with axial ligands aligned in parallel planes (Type II), and those having the novel (d(xz),d(yz))(4)(d(xy))(1) electronic ground state (Type III). A subset of the latter type, with planar axial ligands aligned parallel to each other or strong macrocycle asymmetry that yield rhombic EPR spectra, cannot be created using the porphyrinate ligand. Type I centers are characterized by "large g(max)" EPR spectra with g>3.2 and well-resolved, widely spread magnetic Mössbauer spectra having A(zz)/ g(N)mu(N)>680 kG, with A(xx) negative in sign but much smaller in magnitude than A(zz), while Type II centers have well-resolved rhombic EPR spectra with g(zz)=2.4-3.1 and also less-resolved magnetic Mössbauer spectra, and usually have A(zz)/ g(Nmu(N) in the range of 440-660 kG (but in certain cases as small as 180 kG) and A(xx) again negative in sign but only somewhat smaller (but occasionally larger in magnitude) than A(zz), and Type III centers have axial EPR spectra with g( upper left and right quadrants ) approximately 2.6 or smaller and g( vertical line )<1.0-1.95, but often not resolved, and less-resolved magnetic Mössbauer spectra having A(zz)/ g(N)mu(N) in the range of 270-400 kG, and A(xx) again negative in sign but much smaller in magnitude than A(zz). An exception to this rule is [TPPFe(4-CNPy)(2)](+), which has A(xx)/ g(N)mu(N)=-565 kG, A(yy)/ g(N)mu(N)=629 kG, and A(zz)/ g(N)mu(N)=4 kG. A subset of Type II complexes (Type II') have rhombicities ( V/Delta) much greater than 0.67 and A(zz)/ g(N)mu(N) ranging from 320 to 170 kG, with A(xx) also negative but with the magnitude of A(xx) significantly larger than that of A(zz). These classifications are also observed for a variety of ferriheme proteins, and they lead to linear correlations between A(zz) and either A(xx), g(zz), or V/Delta for Types I and II (but not for A(zz) versus V/Delta for Type II'). Not enough data are yet available on Type III complexes to determine what, if any, correlations may be observed.
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Affiliation(s)
- Rüdiger Benda
- Institut für Physik, Universität Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
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Double KL, Gerlach M, Schünemann V, Trautwein AX, Zecca L, Gallorini M, Youdim MBH, Riederer P, Ben-Shachar D. Iron-binding characteristics of neuromelanin of the human substantia nigra. Biochem Pharmacol 2003; 66:489-94. [PMID: 12907248 DOI: 10.1016/s0006-2952(03)00293-4] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The vulnerability of the dopaminergic neurons of the substantia nigra (SN) in Parkinson's disease has been related to the presence of the pigment neuromelanin (NM) in these neurons. It is hypothesised that NM may act as an endogenous storage molecule for iron, an interaction suggested to influence free radical production. The current study quantified and characterised the interaction between NM and iron. Iron-binding studies demonstrated that both NM and synthetically-produced dopamine melanin contain equivalent numbers of high and low-affinity binding sites for iron but that the affinity of NM for iron is higher than that of synthetic melanin. Quantification of the total iron content in iron-loaded NM and synthetic melanin demonstrated that the iron-binding capacity of NM is 10-fold greater than that of the model melanin. This data was in agreement with the larger iron cluster size demonstrated by Mössbauer spectroscopy in the native pigment compared with the synthetic melanin. These findings are consistent with the hypothesis that NM may act as an endogenous iron-binding molecule in dopaminergic neurons of the SN in the human brain. The interaction between NM and iron has implications for disorders such as Parkinson's disease where an increase in iron in the SN is associated with increased indices of oxidative stress.
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Affiliation(s)
- Kay L Double
- Prince of Wales Medical Research Institute, University of New South Wales, Barker Street, Randwick, Sydney, NSW 2031, Australia.
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Tse Sum Bui B, Benda R, Schünemann V, Florentin D, Trautwein AX, Marquet A. Fate of the (2Fe-2S)(2+) cluster of Escherichia coli biotin synthase during reaction: a Mössbauer characterization. Biochemistry 2003; 42:8791-8. [PMID: 12873140 DOI: 10.1021/bi034426c] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biotin synthase, the enzyme which catalyzes the last step of the biosynthesis of biotin, contains only (2Fe-2S)(2+) clusters when isolated under aerobic conditions. Previous results showed that reduction by dithionite or photoreduced deazaflavin converts the (2Fe-2S)(2+) to (4Fe-4S)(2+,+). However, until now, no detailed investigation concerning the fate of the (2Fe-2S)(2+) during reduction under assay conditions (NADPH, flavodoxin, flavodoxin reductase) has been realized. Here, we show by Mössbauer spectroscopy on a partially purified fraction overexpressing the enzyme that, in the presence of a S(2)(-) source and Fe(2+), there is conversion of the predominant (2Fe-2S)(2+) clusters into a 1:1 mixture of (2Fe-2S)(2+) and (4Fe-4S)(2+). No change in this cluster composition was observed in the presence of the physiological reducing system. When the reaction was allowed to proceed by addition of the substrate dethiobiotin, the (4Fe-4S)(2+) was untouched whereas the (2Fe-2S)(2+) was degraded into a new species. This is consistent with the hypothesis that the reduced (4Fe-4S) cluster is involved in mediating the cleavage of AdoMet and that the (2Fe-2S)(2+) is the sulfur source for biotin.
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Affiliation(s)
- Bernadette Tse Sum Bui
- Laboratoire de Chimie Organique Biologique, Université Paris VI, UMR CNRS 7613, 4 Place Jussieu, 75252 Paris Cedex 05, France
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Walker F, Yatsunyk L, Carducci MD, Teschner T, Schënemann V, Trautwein AX. Correlation of molecular structure, EPR and moessbauer spectral type and reduction potential in low-spin ferriheme models of the cytochromes. J Inorg Biochem 2003. [DOI: 10.1016/s0162-0134(03)80800-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Matzanke BF, Lesuisse E, Schünemann V, Trautwein AX, Meyer-Klaucke W. Spectroscopic characterization of iron deposits in a yeast model(YFH1-) of Friedreich's Ataxia. J Inorg Biochem 2003. [DOI: 10.1016/s0162-0134(03)80707-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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Benda R, Tse Sum Bui B, Schünemann V, Florentin D, Marquet A, Trautwein AX. Iron-sulfur clusters of biotin synthase in vivo: a Mössbauer study. Biochemistry 2002; 41:15000-6. [PMID: 12475249 DOI: 10.1021/bi026590q] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biotin synthase, the enzyme that catalyzes the last step of the biosynthesis of biotin, contains only [2Fe-2S](2+) clusters when isolated under aerobic conditions. Previous results showed that reconstitution with an excess of FeCl(3) and Na(2)S under reducing and anaerobic conditions leads to either [4Fe-4S](2+), [4Fe-4S](+), or a mixture of [4Fe-4S](2+) and [2Fe-2S](2+) clusters. To determine whether any of these possibilities or other different cluster configuration could correspond to the physiological in vivo state, we have used (57)Fe Mössbauer spectroscopy to investigate the clusters of biotin synthase in whole cells. The results show that, in aerobically grown cells, biotin synthase contains a mixture of [4Fe-4S](2+) and [2Fe-2S](2+) clusters. A mixed [4Fe-4S](2+):[2Fe-2S](2+) cluster form has already been observed under certain in vitro conditions, and it has been proposed that both clusters might each play a significant role in the mechanism of biotin synthase. Their presence in vivo is now another argument in favor of this mixed cluster form.
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Affiliation(s)
- Rüdiger Benda
- Institut für Physik, Universität zu Lübeck, Ratzeburger Allee 160, Germany
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41
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Herta C, Winkler H, Benda R, Haas M, Trautwein AX. Dynamic structural disorder of the FeO2 moiety in oxymyoglobin studied by nuclear resonant forward scattering of synchrotron radiation. Eur Biophys J 2002; 31:478-84. [PMID: 12355257 DOI: 10.1007/s00249-002-0237-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2002] [Revised: 05/06/2002] [Accepted: 05/16/2002] [Indexed: 10/27/2022]
Abstract
Oxy- as well as deoxymyoglobin exhibit a pronounced temperature dependence of the quadrupole splitting of the heme iron as detected by conventional Mössbauer spectroscopy. With nuclear resonant forward scattering (NFS) of synchrotron radiation, which can be viewed as Mössbauer spectroscopy in the time domain, it is shown that this spectroscopic behavior, although it is phenomenologically similar in the two cases, is based on completely different physical mechanisms. It is demonstrated that stochastic fluctuations of the iron electric field gradient in MbO(2), which are due to the dynamic structural disorder of the FeO(2) moiety, are the reason for the temperature-dependent alterations of the coherent quantum beat pattern in the NFS spectra of MbO(2), in contrast to deoxyMb where transitions between orbital states of iron take place. This subtle spectroscopic difference cannot be inferred from conventional Mössbauer spectroscopy.
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Affiliation(s)
- C Herta
- Institut für Physik, Medizinische Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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42
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Schünemann V, Jung C, Terner J, Trautwein AX, Weiss R. Spectroscopic studies of peroxyacetic acid reaction intermediates of cytochrome P450cam and chloroperoxidase. J Inorg Biochem 2002; 91:586-96. [PMID: 12237224 DOI: 10.1016/s0162-0134(02)00476-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is generally assumed that the putative compound I (cpd I) in cytochrome P450 should contain the same electron and spin distribution as is observed for cpd I of peroxidases and catalases and many synthetic cpd I analogues. In these systems one oxidation equivalent resides on the Fe(IV)=O unit (d(4), S=1) and one is located on the porphyrin (S'=1/2), constituting a magnetically coupled ferryl iron-oxo porphyrin pi-cation radical system. However, this laboratory has recently reported detection of a ferryl iron (S=1) and a tyrosyl radical (S'=1/2), via Mössbauer and EPR studies of 8 ms-reaction intermediates of substrate-free P450cam from Pseudomonas putida, prepared by a freeze-quench method using peroxyacetic acid as the oxidizing agent [Schünemann et al., FEBS Lett. 479 (2000) 149]. In the present study we show that under the same reaction conditions, but in the presence of the substrate camphor, only trace amounts of the tyrosine radical are formed and no Fe(IV) is detectable. We conclude that camphor restricts the access of the heme pocket by peroxyacetic acid. This conclusion is supported by the additional finding that binding of camphor and metyrapone inhibit heme bleaching at room temperature and longer reaction times, forming only trace amounts of 5-hydroxy-camphor, the hydroxylation product of camphor, during peroxyacetic acid oxidation. As a control we performed freeze-quench experiments with chloroperoxidase from Caldariomyces fumago using peroxyacetic acid under the identical conditions used for the substrate-free P450cam oxidations. We were able to confirm earlier findings [Rutter et al., Biochemistry 23 (1984) 6809], that an antiferromagnetically coupled Fe(IV)=O porphyrin pi-cation radical system is formed. We conclude that CPO and P450 behave differently when reacting with peracids during an 8-ms reaction time. In P450cam the formation of Fe(IV) is accompanied by the formation of a tyrosine radical, whereas in CPO Fe(IV) formation is accompanied by the formation of a porphyrin radical.
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Affiliation(s)
- V Schünemann
- Institute of Physics, Medical University Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
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43
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Saalfrank RW, Reimann U, Göritz M, Hampel F, Scheurer A, Heinemann FW, Büschel M, Daub J, Schünemann V, Trautwein AX. Metal- and ligand-directed one-pot syntheses, crystal structures, and properties of novel oxo-centered tetra- and hexametallic clusters. Chemistry 2002; 8:3614-9. [PMID: 12203287 DOI: 10.1002/1521-3765(20020816)8:16<3614::aid-chem3614>3.0.co;2-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Starting from closely related metal-ligand combinations, completely different oligomeric metal clusters are synthesized. Whereas, picoline-tetrazolylamide HL(1) (1) and zinc or nickel acetate afforded [2x2] grids [M(4)(L(1))(8)] (2), slightly different N-(2-methylthiazole-5-yl)-thiazole-2-carboxamide HL(2) (5 a) and nickel acetate yielded the monometallic complex [Ni(L(2))(2)(OH(2))(2)] (6). In contrast, reaction of 5 a with zinc acetate produced the tetrametallic zinc cluster [Zn(4)O(L(2))(4)(OAc)(2)] (7). Even more surprising, when 3-methyl-substituted HL(3) (5 b) instead of 2-methyl-substituted HL(2) (5 a) was allowed to react under identical conditions with zinc acetate, the cluster [Zn(4)O(L(3))(4)Cl(2)] (8) crystallized from dichloromethane. Clusters 7 and 8 are isostructural. As for 7, in 8 two of the edges of the tetrahedron of zinc ions are doubly bridged, two are singly bridged, and the other two are nonbridged. On the other hand, when iron(II) acetate under aerobic conditions was allowed to react with 5 a, the unprecedented complex [[Fe(3)O(L(2))(2)(OAc)(4)](2)O] (9) was isolated. Cluster 9 is composed of two trimetallic, triangular mu(3)-O(2-)-centered [Fe(3)O(L(2))(2)(OAc)(4)](+) modules, linked by an almost linear mu(2)-O(2-) bridge. The Mössbauer spectrum together with cyclic voltammetric and square-wave voltammetric measurements of 9 are reported, and 6-9 were characterized unequivocally by single-crystal X-ray structure analyses.
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Affiliation(s)
- Rolf W Saalfrank
- Institut für Organische Chemie der Universität, Erlangen-Nürnberg Henkestrasse 42, Germany.
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Kopriva S, Büchert T, Fritz G, Suter M, Benda R, Schünemann V, Koprivova A, Schürmann P, Trautwein AX, Kroneck PMH, Brunold C. The presence of an iron-sulfur cluster in adenosine 5'-phosphosulfate reductase separates organisms utilizing adenosine 5'-phosphosulfate and phosphoadenosine 5'-phosphosulfate for sulfate assimilation. J Biol Chem 2002; 277:21786-91. [PMID: 11940598 DOI: 10.1074/jbc.m202152200] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It was generally accepted that plants, algae, and phototrophic bacteria use adenosine 5'-phosphosulfate (APS) for assimilatory sulfate reduction, whereas bacteria and fungi use phosphoadenosine 5'-phosphosulfate (PAPS). The corresponding enzymes, APS and PAPS reductase, share 25-30% identical amino acids. Phylogenetic analysis of APS and PAPS reductase amino acid sequences from different organisms, which were retrieved from the GenBank(TM), revealed two clusters. The first cluster comprised known PAPS reductases from enteric bacteria, cyanobacteria, and yeast. On the other hand, plant APS reductase sequences were clustered together with many bacterial ones, including those from Pseudomonas and Rhizobium. The gene for APS reductase cloned from the APS-reducing cyanobacterium Plectonema also clustered together with the plant sequences, confirming that the two classes of sequences represent PAPS and APS reductases, respectively. Compared with the PAPS reductase, all sequences of the APS reductase cluster contained two additional cysteine pairs homologous to the cysteine residues involved in binding an iron-sulfur cluster in plants. Mössbauer analysis revealed that the recombinant APS reductase from Pseudomonas aeruginosa contains a [4Fe-4S] cluster with the same characteristics as the plant enzyme. We conclude, therefore, that the presence of an iron-sulfur cluster determines the APS specificity of the sulfate-reducing enzymes and thus separates the APS- and PAPS-dependent assimilatory sulfate reduction pathways.
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Affiliation(s)
- Stanislav Kopriva
- Institute of Forest Botany and Tree Physiology, Albert-Ludwigs-University, D-79085 Freiburg, Germany.
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Zakharieva O, Schünemann V, Gerdan M, Licoccia S, Cai S, Walker FA, Trautwein AX. Is the corrolate macrocycle innocent or noninnocent? Magnetic susceptibility, Mössbauer, 1H NMR, and DFT investigations of chloro- and phenyliron corrolates. J Am Chem Soc 2002; 124:6636-48. [PMID: 12047184 DOI: 10.1021/ja012701h] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In an attempt to determine the electron configuration of (anion)iron corrolates, i.e., whether they are S = 1 Fe(IV)-corrolate(3-) or S = 3/2 Fe(III)-corrolate(2-*), with antiferromagnetic coupling between the iron and macrocycle electrons to yield overall S = 1, two axial ligand complexes of an iron octaalkylcorrolate have been studied by temperature-dependent magnetic susceptibility, magnetic Mössbauer, and 1H NMR spectroscopy, and the results have been compared to those determined on the basis of spin-unrestricted DFT calculations. Magnetic susceptibility measurements indicate the presence of a noninnocent macrocycle (corrolate (2-*)) for the chloroiron corrolate, with strong antiferromagnetic coupling to the S = 3/2 Fe(III) center, while those for the phenyliron corrolate are not conclusive as to the electron configuration. Temperature- and field-dependent Mössbauer spectroscopic investigations of these two complexes yielded spectra that could be simulated with either electron configuration, except that the isomer shift of the phenyl-iron complex is -0.10 mm/s while that of the chloroiron complex is +0.21 mm/s, suggesting that the iron in the former is Fe(IV) while in the latter it is Fe(III). 1H NMR spectroscopic studies of both axial ligand complexes show large negative spin density at the meso carbons, with those of the chloroiron complex (Cai, S.; Walker, F. A.; Licoccia, S. Inorg. Chem. 2000, 39, 3466) being roughly four times larger than those of the phenyliron complex. The temperature dependence of the proton chemical shifts of the phenyliron complex is strictly linear. DFT calculations are consistent with the chloroiron complex being formulated as S1 = 3/2 Fe(III)-corrolate (2-*) S2 = 1/2, with negative spin density at all nitrogens and meso carbons, and a net spin density of -0.79 on the corrolate ring and positive spin density (+0.17) on the chloride ion and +2.58 on the iron. In contrast, the phenyliron complex is best formulated as S = 1 Fe(IV)-corrolate (3-), but again with negative spin density at all nitrogens and meso carbons of the macrocycle, yet with the net spin density on the corrolate ring being virtually zero; the phenyl carbanion carbon has relatively large negative spin density of -0.15 and the iron +2.05. On the basis of all of the results, we conclude that in both the chloroiron and phenyliron complexes the corrolate ring is noninnocent, in the chloroiron complex to a much larger extent than in the phenyliron complex.
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Affiliation(s)
- Olga Zakharieva
- Contribution from the Institut für Physik, Medizinische Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Chang HR, McCusker JK, Toftlund H, Wilson SR, Trautwein AX, Winkler H, Hendrickson DN. [Tetrakis(2-pyridylmethyl)ethylenediamine]iron(II) perchlorate, the first rapidly interconverting ferrous spin-crossover complex. J Am Chem Soc 2002. [DOI: 10.1021/ja00175a012] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Desbois MH, Astruc D, Guillin J, Varret F, Trautwein AX, Villeneuve G. Organometallic electron reservoirs. Part 36. Binuclear electron reservoir complexes. Syntheses, reactivity, and electronic structure of the 37- and 38-electron fulvalene complexes. J Am Chem Soc 2002. [DOI: 10.1021/ja00197a046] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Flassbeck C, Wieghardt K, Bill E, Butzlaff C, Trautwein AX, Nuber B, Weiss J. Coordination of 4,7-bis(2-hydroxybenzyl)-1-oxa-4,7-diazacyclononane (LH2) with manganese(II) and -(III) and zinc(II). Crystal structure of [(LH)2Zn2(.mu.-OH)](PF6).cntdot.0.5CH3OH. Inorg Chem 2002. [DOI: 10.1021/ic00027a006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chaudhuri P, Karpenstein I, Winter M, Lengen M, Butzlaff C, Bill E, Trautwein AX, Floerke U, Haupt HJ. An imidazolate-bridged tetranuclear copper(II) complex: synthesis, magnetic and EPR studies, and crystal structure of [L4Cu4(Im)4](ClO4)4.2H2O (L = 1,4,7-triazacyclononane, Im = imidazolate anion). Inorg Chem 2002. [DOI: 10.1021/ic00058a023] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Birkelbach F, Winter M, Floerke U, Haupt HJ, Butzlaff C, Lengen M, Bill E, Trautwein AX, Wieghardt K, Chaudhuri P. Exchange Coupling in Homo- and Heterodinuclear Complexes CuIIM [M = Cr(III), Mn(III), Mn(II), Fe(III), Co(III), Co(II), Ni(II), Cu(II), Zn(II)]. Synthesis, Structures, and Spectroscopic Properties. Inorg Chem 2002. [DOI: 10.1021/ic00096a025] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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