1
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Wilson DWN, Fataftah MS, Mathe Z, Mercado BQ, DeBeer S, Holland PL. Three-Coordinate Nickel and Metal-Metal Interactions in a Heterometallic Iron-Sulfur Cluster. J Am Chem Soc 2024; 146:4013-4025. [PMID: 38308743 PMCID: PMC10993082 DOI: 10.1021/jacs.3c12157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
Biological multielectron reactions often are performed by metalloenzymes with heterometallic sites, such as anaerobic carbon monoxide dehydrogenase (CODH), which has a nickel-iron-sulfide cubane with a possible three-coordinate nickel site. Here, we isolate the first synthetic iron-sulfur clusters having a nickel atom with only three donors, showing that this structural feature is feasible. These have a core with two tetrahedral irons, one octahedral tungsten, and a three-coordinate nickel connected by sulfide and thiolate bridges. Electron paramagnetic resonance (EPR), Mössbauer, and superconducting quantum interference device (SQUID) data are combined with density functional theory (DFT) computations to show how the electronic structure of the cluster arises from strong magnetic coupling between the Ni, Fe, and W sites. X-ray absorption spectroscopy, together with spectroscopically validated DFT analysis, suggests that the electronic structure can be described with a formal Ni1+ atom participating in a nonpolar Ni-W σ-bond. This metal-metal bond, which minimizes spin density at Ni1+, is conserved in two cluster oxidation states. Fe-W bonding is found in all clusters, in one case stabilizing a local non-Hund state at tungsten. Based on these results, we compare different M-M interactions and speculate that other heterometallic clusters, including metalloenzyme active sites, could likewise store redox equivalents and stabilize low-valent metal centers through metal-metal bonding.
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Affiliation(s)
- Daniel W. N. Wilson
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
| | - Majed S. Fataftah
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
| | - Zachary Mathe
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Brandon Q. Mercado
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Patrick L. Holland
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
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2
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Brown AC, Suess DLM. An Open-Cuboidal [Fe 3S 4] Cluster Characterized in Both Biologically Relevant Redox States. J Am Chem Soc 2023; 145:2075-2080. [PMID: 36688844 DOI: 10.1021/jacs.2c13126] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Synthetic analogues of the three common types of Fe-S clusters found in biology─diamond-core [Fe2S2] clusters, open-cuboidal [Fe3S4] clusters, and cuboidal [Fe4S4] clusters─have been reported in each biologically relevant redox state with one exception: the open-cuboidal [Fe3S4]+ cluster. Here, we describe the synthesis and characterization of an open-cuboidal [Fe3S4] cluster in both biologically relevant redox states: [Fe3S4]+ and [Fe3S4]0. Like their biological counterparts, the oxidized cluster has a spin-canted, S = 1/2 ground state, and the reduced cluster has an S = 2 ground state. Structural analysis reveals that the [Fe3S4] core undergoes substantial contraction upon oxidation, in contrast to the minimal structural changes observed for the only [Fe3S4] protein for which high-resolution structures are available in both redox states (Azotobacter vinelandii ferredoxin I; Av FdI). This difference between the synthetic models and Av FdI is discussed in the context of electron transfer by [Fe3S4] proteins.
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Affiliation(s)
- Alexandra C Brown
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Daniel L M Suess
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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3
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SantaLucia DJ, Berry JF. Antiferromagnetic Exchange and Metal-Metal Bonding in Roussin's Black Sulfur and Selenium Salts. Inorg Chem 2021; 60:16241-16255. [PMID: 34662109 DOI: 10.1021/acs.inorgchem.1c02052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Atom-efficient syntheses of the tetraethylammonium Roussin black sulfur and selenium salts ((Et4N)[Fe4E3(NO)7], E = S, Se) as well as their 15N-labeled counterparts are described herein. Broken-symmetry DFT calculations were conducted on both complexes to model an antiferromagnetic interaction between the apical {FeNO}7 unit, Sap = 3/2, and the three basal {Fe(NO)2}9 units, Sbas = 1/2. The calculated J values are -1813 and -1467 cm-1 for the sulfur and selenium compounds, respectively. The mechanism for antiferromagnetic exchange in both compounds was deduced to be direct exchange on the basis of the partially overlapping magnetic orbitals with orbital density only residing on the Fe-centers. The obtained Mössbauer parameters are most consistent with the calculated MS = 0 broken-symmetry state for both complexes. The values for J have been determined with variable-temperature 15N NMR experiments. Values of -1660 and -1430 cm-1 for the sulfur and selenium compounds, respectively, were obtained by fits to the variable-temperature NMR data, further validating the broken-symmetry MS = 0 model of the electronic structure.
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Affiliation(s)
- Daniel J SantaLucia
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - John F Berry
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
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4
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Mathivathanan L, Sanakis Y, Raptis RG, Turek P, Boudalis AK. Observation and deconvolution of a unique EPR signal from two cocrystallized spin triangles. Phys Chem Chem Phys 2021; 23:14415-14421. [PMID: 34180472 DOI: 10.1039/d1cp01965a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A 16-line pattern has been theoretically predicted, but hitherto not reported, for the Electron Paramagnetic Resonance (EPR) spectrum of antiferromagnetically coupled CuII triangles experiencing isotropic exchange of isosceles magnetic symmetry. Now, the crystallization of such a triangular species and its X-ray structure determination in a polar space group, R3 (No. 146), has enabled its single crystal EPR study. Its detailed magnetic susceptibility, and X- and Q-band, powder and single crystal EPR spectroscopic study reveals the effect of molecular structure and of Dzyaloshinskii-Moriya interactions (DMI) on the g‖, g⊥ and A‖ parameters of the spectrum; DMI is considered for the first time in such a context. Moreover, careful analysis of the spectrum allows the deconvolution of two slightly different cocrystallized magnetic species.
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Affiliation(s)
- Logesh Mathivathanan
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA and Department of Chemistry, GITAM Institute of Science, Gandhi Institute of Technology and Management (Deemed to be University), Visakhapatnam, AP 530045, India
| | - Yiannis Sanakis
- Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Aghia Paraskevi, Athens, Greece
| | - Raphael G Raptis
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Philippe Turek
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra), Université de Strasbourg, 4 rue Blaise Pascal, CS 90032, F-67081 Strasbourg, France.
| | - Athanassios K Boudalis
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra), Université de Strasbourg, 4 rue Blaise Pascal, CS 90032, F-67081 Strasbourg, France. and Institut de Science et d'Ingénierie Suparamolaiculaires - ISIS, 8 allée Gaspard Monge, BP 70028, F-67083 Strasbourg Cedex, France
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5
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Boudalis AK. Half-Integer Spin Triangles: Old Dogs, New Tricks. Chemistry 2021; 27:7022-7042. [PMID: 33336864 DOI: 10.1002/chem.202004919] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/14/2020] [Indexed: 11/06/2022]
Abstract
Spin triangles, that is, triangular complexes of half-integer spins, are the oldest molecular nanomagnets (MNMs). Their magnetic properties have been studied long before molecular magnetism was delineated as a research field. This Review presents the history of their study, with references to the parallel development of new experimental investigations and new theoretical ideas used for their interpretation. It then presents an indicative list of spin-triangle families to illustrate their chemical diversity. Finally, it makes reference to recent developments in terms of theoretical ideas and new phenomena, as well as to the relevance of spin triangles to spintronic devices and new physics.
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Affiliation(s)
- Athanassios K Boudalis
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, Université de Strasbourg, CNRS, 67000, Strasbourg, France.,Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra), Université de Strasbourg, 4 rue Blaise Pascal, CS 90032, 67081, Strasbourg, France
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6
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Zahariou G, Ioannidis N, Sanakis Y, Pantazis DA. Arrested Substrate Binding Resolves Catalytic Intermediates in Higher-Plant Water Oxidation. Angew Chem Int Ed Engl 2021; 60:3156-3162. [PMID: 33030775 PMCID: PMC7898718 DOI: 10.1002/anie.202012304] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Indexed: 12/05/2022]
Abstract
Among the intermediate catalytic steps of the water-oxidizing Mn4 CaO5 cluster of photosystem II (PSII), the final metastable S3 state is critically important because it binds one substrate and precedes O2 evolution. Herein, we combine X- and Q-band EPR experiments on native and methanol-treated PSII of Spinacia oleracea and show that methanol-treated PSII preparations of the S3 state correspond to a previously uncharacterized high-spin (S=6) species. This is confirmed as a major component also in intact photosynthetic membranes, coexisting with the previously known intermediate-spin conformation (S=3). The high-spin intermediate is assigned to a water-unbound form, with a MnIV3 subunit interacting ferromagnetically via anisotropic exchange with a coordinatively unsaturated MnIV ion. These results resolve and define the structural heterogeneity of the S3 state, providing constraints on the S3 to S4 transition, on substrate identity and delivery pathways, and on the mechanism of O-O bond formation.
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Affiliation(s)
- Georgia Zahariou
- Institute of Nanoscience & Nanotechnology, NCSR “Demokritos”Athens15310Greece
| | - Nikolaos Ioannidis
- Institute of Nanoscience & Nanotechnology, NCSR “Demokritos”Athens15310Greece
| | - Yiannis Sanakis
- Institute of Nanoscience & Nanotechnology, NCSR “Demokritos”Athens15310Greece
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
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7
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Zahariou G, Ioannidis N, Sanakis Y, Pantazis DA. Arrested Substrate Binding Resolves Catalytic Intermediates in Higher‐Plant Water Oxidation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202012304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Georgia Zahariou
- Institute of Nanoscience & Nanotechnology, NCSR “Demokritos” Athens 15310 Greece
| | - Nikolaos Ioannidis
- Institute of Nanoscience & Nanotechnology, NCSR “Demokritos” Athens 15310 Greece
| | - Yiannis Sanakis
- Institute of Nanoscience & Nanotechnology, NCSR “Demokritos” Athens 15310 Greece
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
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8
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Mathivathanan L, Rogez G, Ben Amor N, Robert V, Raptis RG, Boudalis AK. Origin of Ferromagnetism and Magnetic Anisotropy in a Family of Copper(II) Triangles. Chemistry 2020; 26:12769-12784. [DOI: 10.1002/chem.202001028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Logesh Mathivathanan
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute Florida International University Miami FL 33199 USA
| | - Guillaume Rogez
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) CNRS/Université de Strasbourg UMR 7504 67000 Strasbourg France
| | - Nadia Ben Amor
- Laboratoire de Chimie et Physique Quantiques UMR 5626 CNRS/Université Paul Sabatier—Bat. 3R1B4 118 route de Narbonne 31062, Cedex 09 Toulouse France
| | - Vincent Robert
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra) Université de Strasbourg 4 rue Blaise Pascal, CS 90032 67081 Strasbourg France
| | - Raphael G. Raptis
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute Florida International University Miami FL 33199 USA
| | - Athanassios K. Boudalis
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra) Université de Strasbourg 4 rue Blaise Pascal, CS 90032 67081 Strasbourg France
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9
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Shi K, Mathivathanan L, Boudalis AK, Turek P, Chakraborty I, Raptis RG. Nitrite Reduction by Trinuclear Copper Pyrazolate Complexes: An Example of a Catalytic, Synthetic Polynuclear NO Releasing System. Inorg Chem 2019; 58:7537-7544. [DOI: 10.1021/acs.inorgchem.9b00748] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kaige Shi
- Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States
| | - Logesh Mathivathanan
- Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States
| | - Athanassios K. Boudalis
- Institut de Chimie UMR 7177/Université de Strasbourg 4, rue Blaise Pascal/CS 90032, F-67081 Strasbourg CEDEX, France
| | - Philippe Turek
- Institut de Chimie UMR 7177/Université de Strasbourg 4, rue Blaise Pascal/CS 90032, F-67081 Strasbourg CEDEX, France
| | - Indranil Chakraborty
- Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States
| | - Raphael G. Raptis
- Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States
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10
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Robert J, Parizel N, Turek P, Boudalis AK. Relevance of Dzyaloshinskii–Moriya spectral broadenings in promoting spin decoherence: a comparative pulsed-EPR study of two structurally related iron(iii) and chromium(iii) spin-triangle molecular qubits. Phys Chem Chem Phys 2019; 21:19575-19584. [DOI: 10.1039/c9cp03422f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two related iron(iii) and chromium(iii) spin-triangle molecular qubits show coherent driving of their spins, and decoherence that is not significantly affected by Dzyaloshikskii–Moriya spectral broadenings.
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Affiliation(s)
- Jérôme Robert
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra)
- Université de Strasbourg
- F-67081 Strasbourg
- France
- Sorbonne Université
| | - Nathalie Parizel
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra)
- Université de Strasbourg
- F-67081 Strasbourg
- France
| | - Philippe Turek
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra)
- Université de Strasbourg
- F-67081 Strasbourg
- France
| | - Athanassios K. Boudalis
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra)
- Université de Strasbourg
- F-67081 Strasbourg
- France
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11
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Boudalis AK, Rogez G, Turek P. Determination of the Distributions of the Spin-Hamiltonian Parameters in Spin Triangles: A Combined Magnetic Susceptometry and Electron Paramagnetic Resonance Spectroscopic Study of the Highly Symmetric [Cr3O(PhCOO)6(py)3](ClO4)·0.5py. Inorg Chem 2018; 57:13259-13269. [DOI: 10.1021/acs.inorgchem.8b01764] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Athanassios K. Boudalis
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra), Université de Strasbourg, 4 rue Blaise Pascal, CS 90032, F-67081 Strasbourg, France
| | - Guillaume Rogez
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504, F-67000 Strasbourg, France
| | - Philippe Turek
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra), Université de Strasbourg, 4 rue Blaise Pascal, CS 90032, F-67081 Strasbourg, France
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12
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Mathivathanan L, Boudalis AK, Turek P, Pissas M, Sanakis Y, Raptis RG. Interactions between H-bonded [CuII3(μ3-OH)] triangles; a combined magnetic susceptibility and EPR study. Phys Chem Chem Phys 2018; 20:17234-17244. [DOI: 10.1039/c8cp02643b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
X-band EPR spectroscopy and magnetic susceptibility studies elucidate the magnetic exchange scheme within a triangular CuII3(μ3-OH) complex and the intermolecular dipolar interactions between two H-bonded CuII3(μ3-OH) units.
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Affiliation(s)
- Logesh Mathivathanan
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute
- Florida International University
- Miami
- USA
| | - Athanassios K. Boudalis
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute
- Florida International University
- Miami
- USA
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra)
| | - Philippe Turek
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra)
- Université de Strasbourg
- F-67081 Strasbourg
- France
| | - Michael Pissas
- Institute of Nanoscience and Nanotechnology
- NCSR “Demokritos”
- Athens
- Greece
| | - Yiannis Sanakis
- Institute of Nanoscience and Nanotechnology
- NCSR “Demokritos”
- Athens
- Greece
| | - Raphael G. Raptis
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute
- Florida International University
- Miami
- USA
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13
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Pellicer Martinez MT, Martinez AB, Crack JC, Holmes JD, Svistunenko DA, Johnston AWB, Cheesman MR, Todd JD, Le Brun NE. Sensing iron availability via the fragile [4Fe-4S] cluster of the bacterial transcriptional repressor RirA. Chem Sci 2017; 8:8451-8463. [PMID: 29619193 PMCID: PMC5863699 DOI: 10.1039/c7sc02801f] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 10/20/2017] [Indexed: 01/02/2023] Open
Abstract
The global iron regulator RirA controls transcription of iron metabolism genes via the binding of a fragile [4Fe–4S] cluster.
Rhizobial iron regulator A (RirA) is a global regulator of iron homeostasis in many nitrogen-fixing Rhizobia and related species of α-proteobacteria. It belongs to the widespread Rrf2 super-family of transcriptional regulators and features three conserved Cys residues that characterise the binding of an iron–sulfur cluster in other Rrf2 family regulators. Here we report biophysical studies demonstrating that RirA contains a [4Fe–4S] cluster, and that this form of the protein binds RirA-regulated DNA, consistent with its function as a repressor of expression of many genes involved in iron uptake. Under low iron conditions, [4Fe–4S] RirA undergoes a cluster conversion reaction resulting in a [2Fe–2S] form, which exhibits much lower affinity for DNA. Under prolonged low iron conditions, the [2Fe–2S] cluster degrades to apo-RirA, which does not bind DNA and can no longer function as a repressor of the cell's iron-uptake machinery. [4Fe–4S] RirA was also found to be sensitive to O2, suggesting that both iron and O2 are important signals for iron metabolism. Consistent with this, in vivo data showed that expression of RirA-regulated genes is also affected by O2. These data lead us to propose a novel regulatory model for iron homeostasis, in which RirA senses iron via the incorporation of a fragile iron–sulfur cluster that is sensitive to iron and O2 concentrations.
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Affiliation(s)
- Ma Teresa Pellicer Martinez
- Centre for Molecular and Structural Biochemistry , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK . ; ; Tel: +44 1603 592699
| | - Ana Bermejo Martinez
- School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK
| | - Jason C Crack
- Centre for Molecular and Structural Biochemistry , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK . ; ; Tel: +44 1603 592699
| | - John D Holmes
- Centre for Molecular and Structural Biochemistry , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK . ; ; Tel: +44 1603 592699
| | - Dimitri A Svistunenko
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester CO4 3SQ , UK
| | - Andrew W B Johnston
- School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK
| | - Myles R Cheesman
- Centre for Molecular and Structural Biochemistry , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK . ; ; Tel: +44 1603 592699
| | - Jonathan D Todd
- School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK
| | - Nick E Le Brun
- Centre for Molecular and Structural Biochemistry , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK . ; ; Tel: +44 1603 592699
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14
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Stoian SA, Peng YR, Beedle CC, Chung YJ, Lee GH, Yang EC, Hill S. Structural, Spectroscopic, and Theoretical Investigation of a T-Shaped [Fe 3(μ 3-O)] Cluster. Inorg Chem 2017; 56:10861-10874. [PMID: 28845975 DOI: 10.1021/acs.inorgchem.7b00455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis, X-ray crystal and electronic structures of [Fe3(μ3-O)(mpmae)2(OAc)2 Cl3], 1, where mpmae-H = 2-(N-methyl-N-((pyridine-2-yl)methyl)amino)ethanol, are described. This cluster comprises three high-spin ferric ions and exhibits a T-shaped site topology. Variable-frequency electron paramagnetic resonance measurements performed on single crystals of 1 demonstrate a total spin ST = 5/2 ground state, characterized by a small, negative, and nearly axial zero-field splitting tensor D = -0.49 cm-1, E/D ≈ 0.055. Analysis of magnetic susceptibility, magnetization, and magneto-structural correlations further corroborate the presence of a sextet ground-spin state. The observed ground state originates from the strong anti-ferromagnetic interaction of two iron(III) spins, with J = 115(5) cm-1, that, in turn, are only weakly coupled to the spin of the third site, with j = 7(1) cm-1. These exchange interactions lead to a ground state with magnetic properties that are essentially entirely determined by the weakly coupled site. The contributions of the individual spins to the total ground state of the cluster were monitored using variable-field 57Fe Mössbauer spectroscopy. Field-dependent spectra reveal that, while one of the iron sites exhibits a large negative internal field, typical of ferric ions, the other two sites exhibit small, but not null, negative and positive internal fields. A theoretical analysis reveals that these small internal fields originate from the mixing of the lowest ST = 5/2 excited state into the ground state which, in turn, is induced by a minute structural distortion.
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Affiliation(s)
| | - Yi-Ru Peng
- Department of Chemistry, Fu Jen Catholic University , Hsinchuang, New Taipei City, 24205 Taiwan, Republic of China
| | | | - Yi-Jung Chung
- Department of Chemistry, Fu Jen Catholic University , Hsinchuang, New Taipei City, 24205 Taiwan, Republic of China
| | - Gene-Hsiang Lee
- Instrumentation Centre, College of Science, National Taiwan University , Taipei, 106 Taiwan, Republic of China
| | - En-Che Yang
- Department of Chemistry, Fu Jen Catholic University , Hsinchuang, New Taipei City, 24205 Taiwan, Republic of China
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15
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Mass spectrometric identification of intermediates in the O 2-driven [4Fe-4S] to [2Fe-2S] cluster conversion in FNR. Proc Natl Acad Sci U S A 2017; 114:E3215-E3223. [PMID: 28373574 DOI: 10.1073/pnas.1620987114] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The iron-sulfur cluster containing protein Fumarate and Nitrate Reduction (FNR) is the master regulator for the switch between anaerobic and aerobic respiration in Escherichia coli and many other bacteria. The [4Fe-4S] cluster functions as the sensory module, undergoing reaction with O2 that leads to conversion to a [2Fe-2S] form with loss of high-affinity DNA binding. Here, we report studies of the FNR cluster conversion reaction using time-resolved electrospray ionization mass spectrometry. The data provide insight into the reaction, permitting the detection of cluster conversion intermediates and products, including a [3Fe-3S] cluster and persulfide-coordinated [2Fe-2S] clusters [[2Fe-2S](S) n , where n = 1 or 2]. Analysis of kinetic data revealed a branched mechanism in which cluster sulfide oxidation occurs in parallel with cluster conversion and not as a subsequent, secondary reaction to generate [2Fe-2S](S) n species. This methodology shows great potential for broad application to studies of protein cofactor-small molecule interactions.
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Georgopoulou AN, Margiolaki I, Psycharis V, Boudalis AK. Dynamic versus Static Character of the Magnetic Jahn–Teller Effect: Magnetostructural Studies of [Fe3O(O2CPh)6(py)3]ClO4·py. Inorg Chem 2017; 56:762-772. [DOI: 10.1021/acs.inorgchem.6b01912] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anastasia N. Georgopoulou
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Agia Paraskevi, Athens 15310, Greece
| | - Irene Margiolaki
- European
Synchrotron Radiation Facility, ESRF, 6 rue Jules Horowitz, B.P. 220, 38043 Grenoble cedex, France
| | - Vassilis Psycharis
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Agia Paraskevi, Athens 15310, Greece
| | - Athanassios K. Boudalis
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Agia Paraskevi, Athens 15310, Greece
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17
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Boudalis AK, Rogez G, Heinrich B, Raptis RG, Turek P. Towards ionic liquids with tailored magnetic properties: bmim+ salts of ferro- and antiferromagnetic CuII3 triangles. Dalton Trans 2017; 46:12263-12273. [DOI: 10.1039/c7dt02472j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
With proper selection of counteraction and pH control, CuII3-pyrazolate anions can form a ferromagnetic low-melting solid, or an antiferromagnetic viscous paste.
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Affiliation(s)
- Athanassios K. Boudalis
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute
- Florida International University
- Miami
- USA
- Institut de Chimie de Strasbourg (UMR 7177
| | - Guillaume Rogez
- Université de Strasbourg
- CNRS
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS)
- UMR 7504
- F-67000 Strasbourg
| | - Benoît Heinrich
- Université de Strasbourg
- CNRS
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS)
- UMR 7504
- F-67000 Strasbourg
| | - Raphael G. Raptis
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute
- Florida International University
- Miami
- USA
| | - Philippe Turek
- Institut de Chimie de Strasbourg (UMR 7177
- CNRS-Unistra)
- Université de Strasbourg
- F-67081 Strasbourg
- France
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18
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Lee Y, Jeon IR, Abboud KA, García-Serres R, Shearer J, Murray LJ. A [3Fe–3S]3+ cluster with exclusively μ-sulfide donors. Chem Commun (Camb) 2016; 52:1174-7. [DOI: 10.1039/c5cc07813j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A [3Fe–3(μ-S)]3+ cluster is reported in which each ferric center has a distorted trigonal pyramidal geometry, with an S = 1/2 ground state for the cluster and unusually anisotropic hyperfine coupling constants as determined by variable temperature magnetometry and Mössbauer spectroscopy.
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Affiliation(s)
- Yousoon Lee
- Department of Chemistry
- Center for Catalysis
- University of Florida
- Gainesville
- USA
| | - Ie-Rang Jeon
- Department of Chemistry
- Northwestern University
- Evanston
- USA
| | - Khalil A. Abboud
- Department of Chemistry
- Center for Catalysis
- University of Florida
- Gainesville
- USA
| | | | - Jason Shearer
- Department of Chemistry
- University of Nevada
- Reno
- Reno
- USA
| | - Leslie J. Murray
- Department of Chemistry
- Center for Catalysis
- University of Florida
- Gainesville
- USA
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19
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Chrisman MA, Baum RR, Grabo JE, Krause JA, Tierney DL, Baldwin MJ. Structure, spectroscopy, stability, and bridge exchange in the M3O4 incomplete-cubane complexes, [M(III)3(Sal-AHA)3(μ-OR)]− (M = Fe, Ga). Polyhedron 2015. [DOI: 10.1016/j.poly.2015.07.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Mössbauer spectroscopy of Fe/S proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1395-405. [PMID: 25498248 DOI: 10.1016/j.bbamcr.2014.12.005] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 11/17/2014] [Accepted: 12/03/2014] [Indexed: 01/02/2023]
Abstract
Iron-sulfur (Fe/S) clusters are structurally and functionally diverse cofactors that are found in all domains of life. (57)Fe Mössbauer spectroscopy is a technique that provides information about the chemical nature of all chemically distinct Fe species contained in a sample, such as Fe oxidation and spin state, nuclearity of a cluster with more than one metal ion, electron spin ground state of the cluster, and delocalization properties in mixed-valent clusters. Moreover, the technique allows for quantitation of all Fe species, when it is used in conjunction with electron paramagnetic resonance (EPR) spectroscopy and analytical methods. (57)Fe-Mössbauer spectroscopy played a pivotal role in unraveling the electronic structures of the "well-established" [2Fe-2S](2+/+), [3Fe-4S](1+/0), and [4Fe-4S](3+/2+/1+/0) clusters and -more-recently- was used to characterize novel Fe/S clustsers, including the [4Fe-3S] cluster of the O2-tolerant hydrogenase from Aquifex aeolicus and the 3Fe-cluster intermediate observed during the reaction of lipoyl synthase, a member of the radical SAM enzyme superfamily.
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21
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Magee SA, Sproules S, Barra AL, Timco GA, Chilton NF, Collison D, Winpenny REP, McInnes EJL. Large zero-field splittings of the ground spin state arising from antisymmetric exchange effects in heterometallic triangles. Angew Chem Int Ed Engl 2014; 53:5310-3. [PMID: 24737709 DOI: 10.1002/anie.201400655] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Indexed: 11/08/2022]
Abstract
[Ru2Mn(O)(O2CtBu)6(py)3] has an S=5/2 ground state with a very large zero-field splitting (ZFS) of D=2.9 cm(-1), as characterized by EPR spectroscopy at 4-330 GHz. This is far too large to be due to the Mn(II) ion (D <0.2 cm(-1)), as shown from the {Fe2Mn} analogue, but can be modeled by antisymmetric exchange effects.
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Affiliation(s)
- Samantha A Magee
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (UK)
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Magee SA, Sproules S, Barra AL, Timco GA, Chilton NF, Collison D, Winpenny REP, McInnes EJL. Large Zero-Field Splittings of the Ground Spin State Arising from Antisymmetric Exchange Effects in Heterometallic Triangles. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Darling K, Ouellette W, Prosvirin A, Walter S, Dunbar KR, Zubieta J. Hydrothermal synthesis and structures of materials of the M(II)/tetrazole/sulfate family (M(II)=Co, Ni; tetrazole=3- and 4-pyridyltetrazole and pyrazinetetrazole). Polyhedron 2013. [DOI: 10.1016/j.poly.2012.07.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Jones S, Aldous A, Burkholder E, Zubieta J. Solid state coordination chemistry of molybdenum oxides: Construction of bimetallic organic–inorganic hybrid materials from Keggin clusters and copper-imine building blocks. Polyhedron 2013. [DOI: 10.1016/j.poly.2012.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Solid state coordination chemistry of metal-azolate compounds: Structural consequences of incorporation of phosphate components in the Co(II)/4-pyridyltetrazolate/phosphate system. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2012.08.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Ferrer S, Lloret F, Pardo E, Clemente-Juan JM, Liu-González M, García-Granda S. Antisymmetric Exchange in Triangular Tricopper(II) Complexes: Correlation among Structural, Magnetic, and Electron Paramagnetic Resonance Parameters. Inorg Chem 2011; 51:985-1001. [DOI: 10.1021/ic2020034] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sacramento Ferrer
- Departament de Química Inorgànica, Universitat de València, Vicent Andrés Estellés
s/n, 46100 Burjassot, Valencia, Spain
| | - Francesc Lloret
- Institut de Ciència Molecular, Universitat de València, Catedràtic José Beltrán
n° 2, 46980 Paterna, Valencia, Spain
| | - Emilio Pardo
- Institut de Ciència Molecular, Universitat de València, Catedràtic José Beltrán
n° 2, 46980 Paterna, Valencia, Spain
| | - Juan Modesto Clemente-Juan
- Institut de Ciència Molecular, Universitat de València, Catedràtic José Beltrán
n° 2, 46980 Paterna, Valencia, Spain
| | - Malva Liu-González
- SCSIE-Rayos X, Universitat de València, Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia,
Spain
| | - Santiago García-Granda
- Departamento de Química
Física y Analítica, Universidad de Oviedo, Julián Clavería 8, 33006 Oviedo, Spain
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Georgopoulou AN, Sanakis Y, Boudalis AK. Magnetic relaxation in basic iron(iii) carboxylate [Fe3O(O2CPh)6(H2O)3]ClO4·py. Dalton Trans 2011; 40:6371-4. [DOI: 10.1039/c1dt10323g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Nakajima H, Takatani N, Yoshimitsu K, Itoh M, Aono S, Takahashi Y, Watanabe Y. The role of the Fe-S cluster in the sensory domain of nitrogenase transcriptional activator VnfA from Azotobacter vinelandii. FEBS J 2010; 277:817-32. [DOI: 10.1111/j.1742-4658.2009.07530.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Tarantul A, Tsukerblat B, Müller A. Field induced crossover in antiferromagnetic spin-frustrated clusters: Influence of static and dynamic structural deformations. J Mol Struct 2008. [DOI: 10.1016/j.molstruc.2008.04.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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31
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Metal trafficking for nitrogen fixation: NifQ donates molybdenum to NifEN/NifH for the biosynthesis of the nitrogenase FeMo-cofactor. Proc Natl Acad Sci U S A 2008; 105:11679-84. [PMID: 18697927 DOI: 10.1073/pnas.0803576105] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molybdenum nitrogenase, present in a diverse group of bacteria and archea, is the major contributor to biological nitrogen fixation. The nitrogenase active site contains an iron-molybdenum cofactor (FeMo-co) composed of 7Fe, 9S, 1Mo, one unidentified light atom, and homocitrate. The nifQ gene was known to be involved in the incorporation of molybdenum into nitrogenase. Here we show direct biochemical evidence for the role of NifQ in FeMo-co biosynthesis. As-isolated NifQ was found to carry a molybdenum-iron-sulfur cluster that serves as a specific molybdenum donor for FeMo-co biosynthesis. Purified NifQ supported in vitro FeMo-co synthesis in the absence of an additional molybdenum source. The mobilization of molybdenum from NifQ required the simultaneous participation of NifH and NifEN in the in vitro FeMo-co synthesis assay, suggesting that NifQ would be the physiological molybdenum donor to a hypothetical NifEN/NifH complex.
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32
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Belinsky MI. Spin-Frustrated Trinuclear Cu(II) Clusters with Mixing of 2(S = 1/2) and S = 3/2 States by Antisymmetric Exchange. 2. Orbital Origin of In-Plane Dzialoshinsky–Moriya Exchange Parameters. Inorg Chem 2008; 47:3532-9. [DOI: 10.1021/ic701797m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Moisey I. Belinsky
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel Aviv, Ramat Aviv 69978, Israel
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Piñero D, Baran P, Boca R, Herchel R, Klein M, Raptis RG, Renz F, Sanakis Y. A pyrazolate-supported Fe(3)(mu(3)-O) core: structural, spectroscopic, electrochemical, and magnetic study. Inorg Chem 2007; 46:10981-9. [PMID: 18044951 PMCID: PMC2597296 DOI: 10.1021/ic0701460] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A comparison is made between the structural, spectroscopic, electrochemical, and magnetic properties of pyrazolate versus carboxylate complexes [Fe3(mu3(mu3O)(mu-LL)6Cl3]2- containing the Fe3(mu3-O)-motif. While the Fe3(mu3-O)-cores are structurally indistinguishable in the two types of complexes, their magnetic properties deviate from the expected values as a result of a through-pyrazole contribution to the overall antiferromagnetic exchange with J1/hc = -80.1 cm(-1) and J2/hc = -72.4 cm(-1), or J1/hc = 70.6 cm(-1) and J2/hc = -80.8 cm(-1), (Hex = -J1(S1S2 + S2S3) - J2S1S3). The magnetic properties of the pyrazolate complexes are further tuned by an antisymmetric exchange interaction term.
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Affiliation(s)
- Dalice Piñero
- Department of Chemistry and the Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931-3346
| | - Peter Baran
- Department of Chemistry and the Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931-3346
| | - Roman Boca
- Department of Inorganic Chemistry, Slovak University of Technology, SK-812 37 Bratislava, Slovakia
- Department of Inorganic Chemistry, Palacký University, Křížkovského 10, CZ-77147 Olomouc, Czech Republic
| | - Radovan Herchel
- Department of Chemistry, University of SS. Cyril and Methodius, Trnava, SK-91701, Slovakia
- Department of Inorganic Chemistry, Palacký University, Křížkovského 10, CZ-77147 Olomouc, Czech Republic
| | - Michael Klein
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University, D-55099 Mainz, Germany
| | - Raphael G. Raptis
- Department of Chemistry and the Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931-3346
| | - Franz Renz
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University, D-55099 Mainz, Germany
| | - Yiannis Sanakis
- Institute of Materials Science, NCRS “Demokritos”, 15310 Aghia Paraskevi, Athens, Greece
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Psycharis V, Raptopoulou CP, Boudalis AK, Sanakis Y, Fardis M, Diamantopoulos G, Papavassiliou G. Syntheses, Structural, and Physical Studies of Basic CrIII and FeIII Benzilates and Benzoates: Evidence of Antisymmetric Exchange and Distributions of Isotropic and Antisymmetric Exchange Parameters. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600306] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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36
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Belinsky MI. Spin–orbit coupling in the double exchange model 2. Comparison of the antisymmetric double exchange with the Dzialoshinsky–Moriya antisymmetric exchange, spin canting and ZFS. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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37
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Boudalis AK, Sanakis Y, Dahan F, Hendrich M, Tuchagues JP. An Octanuclear Complex Containing the {Fe3O}7+ Metal Core: Structural, Magnetic, Mössbauer, and Electron Paramagnetic Resonance Studies. Inorg Chem 2005; 45:443-53. [PMID: 16390088 DOI: 10.1021/ic051652x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new asymmetrically coordinated bis-trinuclear iron(III) cluster containing a [Fe(3)O](7+) core has been synthesized and structurally, magnetically, and spectroscopically characterized. [Fe(6)Na(2)O(2)(O(2)CPh)(10)(pic)(4)(EtOH)(4)(H(2)O)(2)](ClO(4))(2).2EpsilontOH (1.2EpsilontOH) crystallizes in the P space group and consists of two symmetry-related {Fe(3)O](7+) subunits linked by two Na(+) cations. Inside each [Fe(3)O](7+) subunit, the iron(III) ions are antiferromagnetically coupled, and their magnetic exchange is best described by an isosceles triangle model with two equal (J) and one different (J ') coupling constants. On the basis of the H = -2SigmaJ(ij)S(i)S(j) spin Hamiltonian formalism, the two best fits to the data yield solutions J = -27.4 cm(-1), J ' = -20.9 cm(-1) and J = -22.7 cm(-1), J ' = -31.6 cm(-1). The ground state of the cluster is S = (1)/(2). X-band electron paramagnetic resonance (EPR) spectroscopy at liquid-helium temperature reveals a signal comprising a sharp peak at g approximately 2 and a broad tail at higher magnetic fields consistent with the S = (1)/(2) character of the ground state. Variable-temperature zero-field and magnetically perturbed Mössbauer spectra at liquid-helium temperatures are consistent with three antiferromagnetically coupled high-spin ferric ions in agreement with the magnetic susceptibility and EPR results. The EPR and Mössbauer spectra are interpreted by assuming the presence of an antisymmetric exchange interaction with |d| approximately 2-4 cm(-1) and a distribution of exchange constants J(ij).
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Boudalis AK, Sanakis Y, Raptopoulou CP, Terzis A, Tuchagues JP, Perlepes SP. A trinuclear cluster containing the {Fe3(μ3-O)}7+ core: Structural, magnetic and spectroscopic (IR, Mössbauer, EPR) studies. Polyhedron 2005. [DOI: 10.1016/j.poly.2005.04.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Yoon J, Mirica LM, Stack TDP, Solomon EI. Spectroscopic Demonstration of a Large Antisymmetric Exchange Contribution to the Spin-Frustrated Ground State of a D3 Symmetric Hydroxy-Bridged Trinuclear Cu(II) Complex: Ground-to-Excited State Superexchange Pathways. J Am Chem Soc 2004; 126:12586-95. [PMID: 15453791 DOI: 10.1021/ja046380w] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The magnetic and electronic properties of a spin-frustrated ground state of an antiferromagnetically coupled 3-fold symmetric trinuclear copper complex (TrisOH) is investigated using a combination of variable-temperature variable-field magnetic circular dichroism (VTVH MCD) and powder/single-crystal EPR. Direct evidence for a low-lying excited S = (1)/(2) state from the zero-field split ground (2)E state is provided by the nonlinear dependence of the MCD intensity on 1/T and the nesting of the VTVH MCD isotherms. A consistent zero-field splitting (Delta) value of approximately 65 cm(-1) is obtained from both approaches. In addition, the strong angular dependence of the single-crystal EPR spectrum, with effective g-values from 2.32 down to an unprecedented 1.2, requires in-state spin-orbit coupling of the (2)E state via antisymmetric exchange. The observable EPR intensities also require lowering of the symmetry of the trimer structure, likely reflecting a magnetic Jahn-Teller effect. Thus, the Delta of the ground (2)E state is shown to be governed by the competing effects of antisymmetric exchange (G = 36.0 +/- 0.8 cm(-1)) and symmetry lowering (delta = 17.5 +/- 5.0 cm(-1)). G and delta have opposite effects on the spin distribution over the three metal sites where the former tends to delocalize and the latter tends to localize the spin of the S(tot) = (1)/(2) ground state on one metal center. The combined effects lead to partial delocalization, reflected by the observed EPR parallel hyperfine splitting of 74 x 10(-4) cm(-1). The origin of the large G value derives from the efficient superexchange pathway available between the ground d(x2-y2) and excited d(xy) orbitals of adjacent Cu sites, via strong sigma-type bonds with the in-plane p-orbitals of the bridging hydroxy ligands. This study provides significant insight into the orbital origin of the spin Hamiltonian parameters of a spin-frustrated ground state of a trigonal copper cluster.
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Affiliation(s)
- Jungjoo Yoon
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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40
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Vlachos A, Psycharis V, Raptopoulou CP, Lalioti N, Sanakis Y, Diamantopoulos G, Fardis M, Karayanni M, Papavassiliou G, Terzis A. A nearly symmetric trinuclear chromium(III) oxo carboxylate assembly: preparation, molecular and crystal structure, and magnetic properties of [Cr3O(O2CPh)6(MeOH)3](NO3)·2MeOH. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2004.04.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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41
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Tiago de Oliveira F, Bominaar EL, Hirst J, Fee JA, Münck E. Antisymmetric Exchange in [2Fe−2S]1+ Clusters: EPR of the Rieske Protein from Thermus thermophilus at pH 14. J Am Chem Soc 2004; 126:5338-9. [PMID: 15113187 DOI: 10.1021/ja031746a] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[2Fe-2S] clusters found in the xanthine oxidase family of proteins exhibit an S = 1/2 EPR feature, called signal II, for which one g-value is significantly above g = 2.0. The g-values of signal II cannot be explained with the standard spin coupling model that has been so successful in describing the g = 1.94 signals of [2Fe-2S] ferredoxins. We have studied the EPR spectra of the Rieske protein from Thermus thermophilus at pH 14 and observed a signal II-type EPR spectrum, with g-values at 1.81, 1.94, and 2.14. It is shown that the g-values of signal II can be explained by including an antisymmetric exchange term, d.S1xS2, in the spin Hamiltonian. The presence of this term is sensed by EPR if the isotropic exchange coupling constant J is sufficiently small. For the Rieske protein we determined J = 43 cm-1 which is at least 4 times smaller than the J values reported for [2Fe-2S] clusters that yield standard g = 1.94 signals.
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Liu X, de Miranda MP, McInnes EJL, Kilner CA, Halcrow MA. Antisymmetric exchange in two tricopper(ii) complexes containing a [Cu3(μ3-OMe)]5+core. Dalton Trans 2004:59-64. [PMID: 15356742 DOI: 10.1039/b311980g] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of CuX2(X-=Cl- or Br-) with 2 molar equivalents of 3[5]-(2,4,6-trimethylphenyl)pyrazole (HpzMes) in MeOH in the presence of NaOH yields [Cu3X(HpzMes)2(micro-pzMes)3(micro3-OMe)]X (X-=Cl- or Br-). Crystal structures of these compounds show almost identical triangles of Cu(II) ions, centred by a triply bridging methoxide ligand and with three edge-bridging pyrazolide groups. The mesityl substituents on the bridging pyrazolide ligands are arranged in HT, HH, TT fashion. chi(M)T for both compounds decreases steadily with decreasing temperature, reaching 0.40 cm(3) mol(-1) K at 70 K before decreasing further below 40 K. This low temperature behaviour could not be interpreted using conventional superexchange Hamiltonians, but was reproduced by an alternative model that incorporated an additional antisymmetric exchange term. This interpretation was confirmed by the Q-band EPR spectra of the two compounds. NMR experiments show that the structures of these compounds are not retained in solution, in contrast to other closely related tricopper compounds. These are the first examples of triangular Cu(II) compounds bearing a [Cu3micro3-OR)]5+(R is not equal to H) core motif, and the first triangular compounds showing antisymmetric exchange to have been analysed by both susceptibility and EPR measurements.
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Affiliation(s)
- Xiaoming Liu
- Department of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UKLS2 9JT
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Knottenbelt SZ, McGrady JE. On the electronic origins of structural isomerism in the iron-sulfur cubane, [(C(5)H(5))(4)Fe(4)S(4)](2+). J Am Chem Soc 2003; 125:9846-52. [PMID: 12904052 DOI: 10.1021/ja0353053] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Density functional theory provides new insights into the structural isomerism observed in the cyclopentadienyl-capped iron-sulfur cluster, [(C(5)H(5))(4)Fe(4)S(4)](2+). Two distinct, closely spaced minima have been located, a triplet with D(2) symmetry and a C(2)-symmetric singlet, both of which correspond closely to the structure of one of the known crystal forms of the cation. Thus, the structural diversity in these species reflects genuine molecular bistability rather than simple solid-state packing effects. In contrast, no stable D(2)(d)()-symmetric minimum has been located, suggesting that the reported D(2)(d)() symmetry of the cation in [(C(5)H(5))(4)Fe(4)S(4)][PF(6)](2) may be a crystallographic artifact. In the ruthenium analogue, the more diffuse 4d orbitals stabilize the C(2)-symmetric singlet, which is unambiguously the ground state, but the D(2)-symmetric potential energy surface provides a viable low-energy pathway for the dynamic exchange of the Ru-Ru bonds.
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Affiliation(s)
- Sushilla Z Knottenbelt
- Department of Chemistry, The University of York, Heslington, York, YO10 5DD, United Kingdom
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Shultz DA, Vostrikova KE, Bodnar SH, Koo HJ, Whangbo MH, Kirk ML, Depperman EC, Kampf JW. Trends in metal-biradical exchange interaction for first-row M(II)(nitronyl nitroxide-semiquinone) complexes. J Am Chem Soc 2003; 125:1607-17. [PMID: 12568622 DOI: 10.1021/ja020715x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report molecular structures and temperature-dependent magnetic susceptibility data for several new metal complexes of heterospin triplet ground-state biradical ligands. The ligands are comprised of both nitronyl-nitroxide (NN) and semiquinone (SQ) spin carriers. Five compounds are five-coordinate M(II) complexes (M = Mn, Co, Ni, Cu, and Zn), and one is a six-coordinate Ni(II) complex. Five compounds were structurally characterized. During copper complex formation a reaction with methanol occurs to form a unique methoxy-substituted SQ ring. Variable-temperature magnetic susceptibility studies are consistent with strong intraligand (NN-SQ and NN-PhSQ) ferromagnetic exchange coupling. For the five-coordinate Mn, Co, and Ni complexes, the S = 1 ligand is antiferromagnetically coupled to the metal. For both the five-coordinate Cu complex and the six-coordinate Ni complex, the ligand is ferromagnetically coupled to the metal spins in accordance with orbital symmetry arguments. Despite the low molecular symmetries, the predicted trend in metal-ligand exchange interactions is supported by spin dimer analysis based on extended Hückel calculations. For (NN-SQ)NiTp(Cum,Me)() (Tp(Cum,Me)() = hydro-tris(3-cumenyl-5-methylpyrazolyl)borate), an antisymmetric exchange term was required for the best fit of the magnetic susceptibility data. Antisymmetric exchange was less important for the other complexes due to inherently smaller Deltag. Finally, it is shown that intraligand exchange coupling is of paramount importance in stabilizing high-spin states of mixed metal-biradical complexes.
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Affiliation(s)
- David A Shultz
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
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Ferrer S, Lloret F, Bertomeu I, Alzuet G, Borrás J, García-Granda S, Liu-González M, Haasnoot JG. Cyclic trinuclear and chain of cyclic trinuclear copper(II) complexes containing a pyramidal Cu(3)O(H) core. Crystal structures and magnetic properties of [Cu(3)(mu(3)-OH)(aaat)(3)(H(2)O)(3)](NO(3))(2).H(2)O [aaat = 3-acetylamino-5-amino-1,2,4-triazolate] and ([Cu(3)(mu(3)-OH)(aat)(3)(mu(3)-SO(4))].6H(2)O)(n) [aat = 3-acetylamino-1,2,4-triazolate]: new cases of spin-frustrated systems. Inorg Chem 2002; 41:5821-30. [PMID: 12401089 DOI: 10.1021/ic020179+] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
New copper(II) complexes of the cyclic trinuclear type with 1,2,4-triazole ligands, [Cu(3)(mu(3)-OH)(aaat)(3)(H(2)O)(3)](NO(3))(2).H(2)O [Haaat = 3-acetylamino-5-amino-1,2,4-triazole] (1) and ([Cu(3)(mu(3)-OH)(aat)(3)(mu(3)-SO(4))].6H(2)O)(n) [Haat = 3-acetylamino-1,2,4-triazole] (2), have been prepared and characterized by X-ray crystallography and magnetic measurements. Compound 1, the first reported with the ligand (H)aaat, consists of discrete trinuclear cations, associated NO(3)(-) anions and lattice water molecules. Compound 2 consists of unusual chains of trinuclear units with a tridentate sulfato group linking the trimeric units and water molecules stabilizing the crystal lattice. In both complexes, 1 and 2, the trinuclear [Cu(3)(OH)L(3)] unit contains a pyramidal Cu(3)-mu(3)OH core, and an almost flat Cu(3)N(6) ring formed by the N,N-bridging triazolato groups. The Cu...Cu' intratrimeric distances are 3.35-3.37-3.39 A in 1 and 3.34-3.34-3.36 A in 2. The copper atoms are five-coordinated with a distorted square-pyramidal geometry. Magnetic measurements have been performed in the 1.9-300 K temperature range. In the high-temperature region (T > 90 K), experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -J(S(1)S(2) + S(2)S(3) + S(1)S(3)), with J = -194.6 cm(-1) and g = 2.08 for 1, and J = -185.1 cm(-1) and g = 2.10 for 2. The magnitude of the antiferromagnetic exchange in both complexes is discussed on the basis of their structural features by comparison with reported N,N-pheripherically bridged trinuclear systems. In order to fit the experimental magnetic data at low temperature, an antisymmetric exchange term, H(AS) = G(S(1)xS(2) + S(2)xS(3) + S(1)xS(3)), had to be introduced, with G = 27.8 (1) and 31.0 (2) cm(-1). Crystal data: C(12)H(27)Cu(3)N(17)O(14) (1) (MW = 824.13) crystallizes in the triclinic space group, P(-)1, Z = 2, with the cell dimensions a = 8.852(2) A, b = 11.491(3) A, c = 15.404(3) A, alpha = 70.43(3) degrees, beta = 75.11(2) degrees, gamma = 88.43(2) degrees, and V = 1423.8(5) A(3), D(calcd) = 1.922 g cm(-)(3); the final agreement values were R1 = 0.0822 and wR2 = 0.2300 for 4989 unique reflections. C(12)H(28)Cu(3)N(12)O(14)S (2) (MW = 787.14) crystallizes in the triclinic space group, P(-)1, Z = 2, with the cell dimensions a = 7.146(6) A, b = 14.26(1) A, c = 15.35(2) A, alpha = 109.0(9) degrees, beta = 93.6(9) degrees, gamma = 99.5(7) degrees, and V = 1448(2) A(3), D(calcd) = 1.806 g cm(-3); the final agreement values were R1 = 0.0628 and wR2 = 0.1571 for 3997 "observed" reflections.
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Affiliation(s)
- Sacramento Ferrer
- Departament de Química Inorgànica, Universitat de València, 46100 Burjassot, Valencia, Spain.
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Beinert H. Spectroscopy of succinate dehydrogenases, a historical perspective. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1553:7-22. [PMID: 11803014 DOI: 10.1016/s0005-2728(01)00235-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
An attempt is made to retrace, from personal experience, the discovery of redox-reactive non-heme iron in living matter, which turned out to occur in the form of iron-sulfur (Fe-S) clusters, and then to recount the immediate application of this knowledge in exploring the composition of the mitochondrial respiratory chain, and in the rather detailed description of the workings of its components and, for the purposes of the present volume, of succinate dehydrogenase. The relationship of these events to the general status of technology and the available methodology and instrumentation is considered in some detail, with the conclusion that there scarcely was a way that these discoveries could have been made earlier. It is then shown how methods, techniques and interpretations of results were developed and evolved during the applications that were made to a complex problem such as that of the composition, structure and functioning of succinate dehydrogenase. A tabulation of the most significant events--concerning specifically spectroscopy and its interpretations--in this development is given up to the year 2000.
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Affiliation(s)
- Helmut Beinert
- Institute for Enzyme Research and Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison, 1710 University Avenue, Madison, WI 53705-4098, USA.
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