1301
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Gomez-Mingot M, Porcher JP, Todorova TK, Fogeron T, Mellot-Draznieks C, Li Y, Fontecave M. Bioinspired Tungsten Dithiolene Catalysts for Hydrogen Evolution: A Combined Electrochemical, Photochemical, and Computational Study. J Phys Chem B 2015; 119:13524-33. [PMID: 25844501 DOI: 10.1021/acs.jpcb.5b01615] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bis(dithiolene)tungsten complexes, W(VI)O2 (L = dithiolene)2 and W(IV)O (L = dithiolene)2, which mimic the active site of formate dehydrogenases, have been characterized by cyclic voltammetry and controlled potential electrolysis in acetonitrile. They are shown to be able to catalyze the electroreduction of protons into hydrogen in acidic organic media, with good Faradaic yields (75-95%) and good activity (rate constants of 100 s(-1)), with relatively high overpotentials (700 mV). They also catalyze proton reduction into hydrogen upon visible light irradiation, in combination with [Ru(bipyridine)3](2+) as a photosensitizer and ascorbic acid as a sacrificial electron donor. On the basis of detailed DFT calculations, a reaction mechanism is proposed in which the starting W(VI)O2 (L = dithiolene)2 complex acts as a precatalyst and hydrogen is further formed from a key reduced W-hydroxo-hydride intermediate.
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Affiliation(s)
- Maria Gomez-Mingot
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Jean-Philippe Porcher
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Tanya K Todorova
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Thibault Fogeron
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Caroline Mellot-Draznieks
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Yun Li
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
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1302
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Bachmeier A, Esselborn J, Hexter SV, Krämer T, Klein K, Happe T, McGrady JE, Myers WK, Armstrong FA. How Formaldehyde Inhibits Hydrogen Evolution by [FeFe]-Hydrogenases: Determination by ¹³C ENDOR of Direct Fe-C Coordination and Order of Electron and Proton Transfers. J Am Chem Soc 2015; 137:5381-9. [PMID: 25871921 DOI: 10.1021/ja513074m] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Formaldehyde (HCHO), a strong electrophile and a rapid and reversible inhibitor of hydrogen production by [FeFe]-hydrogenases, is used to identify the point in the catalytic cycle at which a highly reactive metal-hydrido species is formed. Investigations of the reaction of Chlamydomonas reinhardtii [FeFe]-hydrogenase with formaldehyde using pulsed-EPR techniques including electron-nuclear double resonance spectroscopy establish that formaldehyde binds close to the active site. Density functional theory calculations support an inhibited super-reduced state having a short Fe-(13)C bond in the 2Fe subsite. The adduct forms when HCHO is available to compete with H(+) transfer to a vacant, nucleophilic Fe site: had H(+) transfer already occurred, the reaction of HCHO with the Fe-hydrido species would lead to methanol, release of which is not detected. Instead, Fe-bound formaldehyde is a metal-hydrido mimic, a locked, inhibited form analogous to that in which two electrons and only one proton have transferred to the H-cluster. The results provide strong support for a mechanism in which the fastest pathway for H2 evolution involves two consecutive proton transfer steps to the H-cluster following transfer of a second electron to the active site.
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Affiliation(s)
- Andreas Bachmeier
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Julian Esselborn
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Suzannah V Hexter
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Tobias Krämer
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Kathrin Klein
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Thomas Happe
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - John E McGrady
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - William K Myers
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Fraser A Armstrong
- †Inorganic Chemistry Laboratory and ‡Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.,§Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie and ∥Lehrstuhl für Anorganische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
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1303
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Abstract
A dinuclear synthetic model of the [NiFeSe] hydrogenase active site and a structural, spectroscopic and electrochemical analysis of this complex is reported. [NiFe(‘S2Se2’)(CO)3] (H2‘S2Se2’=1,2-bis(2-thiabutyl-3,3-dimethyl-4-selenol)benzene) has been synthesized by reacting the nickel selenolate complex [Ni(‘S2Se2’)] with [Fe(CO)3bda] (bda=benzylideneacetone). X-ray crystal structure analysis confirms that [NiFe(‘S2Se2’)(CO)3] mimics the key structural features of the enzyme active site, including a doubly bridged heterobimetallic nickel and iron center with a selenolate terminally coordinated to the nickel center. Comparison of [NiFe(‘S2Se2’)(CO)3] with the previously reported thiolate analogue [NiFe(‘S4’)(CO)3] (H2‘S4’=H2xbsms=1,2-bis(4-mercapto-3,3-dimethyl-2-thiabutyl)benzene) showed that the selenolate groups in [NiFe(‘S2Se2’)(CO)3] give lower carbonyl stretching frequencies in the IR spectrum. Electrochemical studies of [NiFe(‘S2Se2’)(CO)3] and [NiFe(‘S4’)(CO)3] demonstrated that both complexes do not operate as homogenous H2 evolution catalysts, but are precursors to a solid deposit on an electrode surface for H2 evolution catalysis in organic and aqueous solution.
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Affiliation(s)
- Claire Wombwell
- Christian Doppler Laboratory for Sustainable SynGas Chemistry, Department of Chemistry, University of CambridgeLensfield Road, Cambridge CB2 1EW (UK) E-mail: Homepage: http://www-reisner.ch.cam.ac.uk/
| | - Erwin Reisner
- Christian Doppler Laboratory for Sustainable SynGas Chemistry, Department of Chemistry, University of CambridgeLensfield Road, Cambridge CB2 1EW (UK) E-mail: Homepage: http://www-reisner.ch.cam.ac.uk/
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1304
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High-valent metal-oxo intermediates in energy demanding processes: from dioxygen reduction to water splitting. Curr Opin Chem Biol 2015; 25:159-71. [DOI: 10.1016/j.cbpa.2015.01.014] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 11/15/2022]
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1305
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Artificial hydrogenases: biohybrid and supramolecular systems for catalytic hydrogen production or uptake. Curr Opin Chem Biol 2015; 25:36-47. [DOI: 10.1016/j.cbpa.2014.12.018] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/04/2014] [Accepted: 12/11/2014] [Indexed: 11/22/2022]
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1306
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Identification, cloning and heterologous expression of active [NiFe]-hydrogenase 2 from Citrobacter sp. SG in Escherichia coli. J Biotechnol 2015; 199:1-8. [DOI: 10.1016/j.jbiotec.2015.01.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/27/2015] [Accepted: 01/29/2015] [Indexed: 11/22/2022]
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1307
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Fukuzumi S. Artificial photosynthetic systems for production of hydrogen. Curr Opin Chem Biol 2015; 25:18-26. [DOI: 10.1016/j.cbpa.2014.12.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 11/29/2014] [Accepted: 12/02/2014] [Indexed: 11/28/2022]
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1308
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Bachmeier A, Armstrong F. Solar-driven proton and carbon dioxide reduction to fuels — lessons from metalloenzymes. Curr Opin Chem Biol 2015; 25:141-51. [DOI: 10.1016/j.cbpa.2015.01.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/23/2014] [Accepted: 01/07/2015] [Indexed: 01/13/2023]
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1309
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Moore CM, Dahl EW, Szymczak NK. Beyond H2: exploiting 2-hydroxypyridine as a design element from [Fe]-hydrogenase for energy-relevant catalysis. Curr Opin Chem Biol 2015; 25:9-17. [DOI: 10.1016/j.cbpa.2014.11.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 11/21/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
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1310
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Greene BL, Wu CH, McTernan PM, Adams MWW, Dyer RB. Proton-coupled electron transfer dynamics in the catalytic mechanism of a [NiFe]-hydrogenase. J Am Chem Soc 2015; 137:4558-66. [PMID: 25790178 DOI: 10.1021/jacs.5b01791] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The movement of protons and electrons is common to the synthesis of all chemical fuels such as H2. Hydrogenases, which catalyze the reversible reduction of protons, necessitate transport and reactivity between protons and electrons, but a detailed mechanism has thus far been elusive. Here, we use a phototriggered chemical potential jump method to rapidly initiate the proton reduction activity of a [NiFe] hydrogenase. Coupling the photochemical initiation approach to nanosecond transient infrared and visible absorbance spectroscopy afforded direct observation of interfacial electron transfer and active site chemistry. Tuning of intramolecular proton transport by pH and isotopic substitution revealed distinct concerted and stepwise proton-coupled electron transfer mechanisms in catalysis. The observed heterogeneity in the two sequential proton-associated reduction processes suggests a highly engineered protein environment modulating catalysis and implicates three new reaction intermediates; Nia-I, Nia-D, and Nia-SR(-). The results establish an elementary mechanistic understanding of catalysis in a [NiFe] hydrogenase with implications in enzymatic proton-coupled electron transfer and biomimetic catalyst design.
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Affiliation(s)
- Brandon L Greene
- †Chemistry Department, Emory University, Atlanta, Georgia 30322, United States
| | - Chang-Hao Wu
- ‡Department of Biochemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Patrick M McTernan
- ‡Department of Biochemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Michael W W Adams
- ‡Department of Biochemistry, University of Georgia, Athens, Georgia 30602, United States
| | - R Brian Dyer
- †Chemistry Department, Emory University, Atlanta, Georgia 30322, United States
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1311
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Chu KT, Liu YC, Huang YL, Lee GH, Tseng MC, Chiang MH. Redox Communication within Multinuclear Iron-Sulfur Complexes Related to Electronic Interplay in the Active Site of [FeFe]Hydrogenase. Chemistry 2015; 21:6852-61. [DOI: 10.1002/chem.201406101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Indexed: 11/08/2022]
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1312
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Bethel RD, Crouthers DJ, Hsieh CH, Denny JA, Hall MB, Darensbourg MY. Regioselectivity in Ligand Substitution Reactions on Diiron Complexes Governed by Nucleophilic and Electrophilic Ligand Properties. Inorg Chem 2015; 54:3523-35. [DOI: 10.1021/acs.inorgchem.5b00072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryan D. Bethel
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Danielle J. Crouthers
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | | | - Jason A. Denny
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Michael B. Hall
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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1313
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Olechnowicz F, Hillhouse GL, Jordan RF. Synthesis and Reactivity of NHC-Supported Ni2(μ2-η2,η2-S2)-Bridging Disulfide and Ni2(μ-S)2-Bridging Sulfide Complexes. Inorg Chem 2015; 54:2705-12. [DOI: 10.1021/ic502892r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Frank Olechnowicz
- Gordon Center for Integrative Science, Department of
Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Gregory L. Hillhouse
- Gordon Center for Integrative Science, Department of
Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Richard F. Jordan
- Gordon Center for Integrative Science, Department of
Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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1314
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Huang GF, Wu XB, Bai LP, Liu K, Jiang LJ, Long MN, Chen QX. Improved O2-tolerance in variants of a H2-evolving [NiFe]-hydrogenase from Klebsiella oxytoca HP1. FEBS Lett 2015; 589:910-8. [PMID: 25747389 DOI: 10.1016/j.febslet.2015.02.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 02/14/2015] [Accepted: 02/23/2015] [Indexed: 12/29/2022]
Abstract
In this study, we investigated the mechanism of O2 tolerance of Klebsiella oxytoca HP1 H2-evolving hydrogenase 3 (KHyd3) by mutational analysis and three-dimensional structure modeling. Results revealed that certain surface amino acid residues of KHyd3 large subunit, in particular those at the outer entrance of the gas channel, have a visible effect on its oxygen tolerance. Additionally, solution pH, immobilization and O2 partial pressure also affect KHyd3 O2-tolerance to some extent. We propose that the extent of KHyd3 O2-tolerance is determined by a balance between the rate of O2 access to the active center through gas channels and the deoxidation rate of the oxidized active center. Based on our findings, two higher O2-tolerant KHyd3 mutations G300E and G300M were developed.
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Affiliation(s)
- Gang-Feng Huang
- State Key Laboratory of Cellular Stress Biology and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Xiao-Bing Wu
- State Key Laboratory of Cellular Stress Biology and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China.
| | - Li-Ping Bai
- State Key Laboratory of Cellular Stress Biology and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Ke Liu
- State Key Laboratory of Cellular Stress Biology and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Li-Jing Jiang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
| | - Min-Nan Long
- School of Energy Research, Xiamen University, Xiamen 361102, China
| | - Qing-Xi Chen
- State Key Laboratory of Cellular Stress Biology and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China.
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1315
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Brown HJS, Wiese S, Roberts JAS, Bullock RM, Helm ML. Electrocatalytic Hydrogen Production by [Ni(7PPh2NH)2]2+: Removing the Distinction Between Endo- and Exo-Protonation Sites. ACS Catal 2015. [DOI: 10.1021/cs502132y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Houston J. S. Brown
- Center for Molecular Electrocatalysis, Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, K2-57, Richland, Washington 99352, United States
| | - Stefan Wiese
- Center for Molecular Electrocatalysis, Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, K2-57, Richland, Washington 99352, United States
| | - John A. S. Roberts
- Center for Molecular Electrocatalysis, Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, K2-57, Richland, Washington 99352, United States
| | - R. Morris Bullock
- Center for Molecular Electrocatalysis, Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, K2-57, Richland, Washington 99352, United States
| | - Monte L. Helm
- Center for Molecular Electrocatalysis, Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, K2-57, Richland, Washington 99352, United States
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1316
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Rettenmeier CA, Wadepohl H, Gade LH. Structural Characterization of a Hydroperoxo Nickel Complex and Its Autoxidation: Mechanism of Interconversion between Peroxo, Superoxo, and Hydroperoxo Species. Angew Chem Int Ed Engl 2015; 54:4880-4. [DOI: 10.1002/anie.201500141] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Indexed: 11/06/2022]
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1317
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Rettenmeier CA, Wadepohl H, Gade LH. Structural Characterization of a Hydroperoxo Nickel Complex and Its Autoxidation: Mechanism of Interconversion between Peroxo, Superoxo, and Hydroperoxo Species. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201500141] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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1318
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Cutsail GE, Telser J, Hoffman BM. Advanced paramagnetic resonance spectroscopies of iron-sulfur proteins: Electron nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM). BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1370-94. [PMID: 25686535 DOI: 10.1016/j.bbamcr.2015.01.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/29/2015] [Accepted: 01/29/2015] [Indexed: 12/20/2022]
Abstract
The advanced electron paramagnetic resonance (EPR) techniques, electron nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM) spectroscopies, provide unique insights into the structure, coordination chemistry, and biochemical mechanism of nature's widely distributed iron-sulfur cluster (FeS) proteins. This review describes the ENDOR and ESEEM techniques and then provides a series of case studies on their application to a wide variety of FeS proteins including ferredoxins, nitrogenase, and radical SAM enzymes. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- George E Cutsail
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, IL 60605, USA
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA.
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1319
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Siebel JF, Adamska-Venkatesh A, Weber K, Rumpel S, Reijerse E, Lubitz W. Hybrid [FeFe]-hydrogenases with modified active sites show remarkable residual enzymatic activity. Biochemistry 2015; 54:1474-83. [PMID: 25633077 DOI: 10.1021/bi501391d] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
[FeFe]-hydrogenases are to date the only enzymes for which it has been demonstrated that the native inorganic binuclear cofactor of the active site Fe2(adt)(CO)3(CN)2 (adt = azadithiolate = [S-CH2-NH-CH2-S](2-)) can be synthesized on the laboratory bench and subsequently inserted into the unmaturated enzyme to yield fully functional holo-enzyme (Berggren, G. et al. (2013) Nature 499, 66-70; Esselborn, J. et al. (2013) Nat. Chem. Biol. 9, 607-610). In the current study, we exploit this procedure to introduce non-native cofactors into the enzyme. Mimics of the binuclear subcluster with a modified bridging dithiolate ligand (thiodithiolate, N-methylazadithiolate, dimethyl-azadithiolate) and three variants containing only one CN(-) ligand were inserted into the active site of the enzyme. We investigated the activity of these variants for hydrogen oxidation as well as proton reduction and their structural accommodation within the active site was analyzed using Fourier transform infrared spectroscopy. Interestingly, the monocyanide variant with the azadithiolate bridge showed ∼50% of the native enzyme activity. This would suggest that the CN(-) ligands are not essential for catalytic activity, but rather serve to anchor the binuclear subsite inside the protein pocket through hydrogen bonding. The inserted artificial cofactors with a propanedithiolate and an N-methylazadithiolate bridge as well as their monocyanide variants also showed residual activity. However, these activities were less than 1% of the native enzyme. Our findings indicate that even small changes in the dithiolate bridge of the binuclear subsite lead to a rather strong decrease of the catalytic activity. We conclude that both the Brønsted base function and the conformational flexibility of the native azadithiolate amine moiety are essential for the high catalytic activity of the native enzyme.
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Affiliation(s)
- Judith F Siebel
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D-45470 Muelheim an der Ruhr, Germany
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1320
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Murray KA, Wodrich MD, Hu X, Corminboeuf C. Toward functional type III [Fe]-hydrogenase biomimics for H2 activation: insights from computation. Chemistry 2015; 21:3987-96. [PMID: 25649221 DOI: 10.1002/chem.201405619] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Indexed: 11/06/2022]
Abstract
The chemistry of [Fe]-hydrogenase has attracted significant interest due to its ability to activate molecular hydrogen. The intriguing properties of this enzyme have prompted the synthesis of numerous small molecule mimics aimed at activating H2. Despite considerable effort, a majority of these compounds remain nonfunctional for hydrogenation reactions. By using a recently synthesized model as an entry point, seven biomimetic complexes have been examined through DFT computations to probe the influence of ligand environment on the ability of a mimic to bind and split H2. One mimic, featuring a bidentate diphosphine group incorporating an internal nitrogen base, was found to have particularly attractive energetics, prompting a study of the role played by the proton/hydride acceptor necessary to complete the catalytic cycle. Computations revealed an experimentally accessible energetic pathway involving a benzaldehyde proton/hydride acceptor and the most promising catalyst.
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Affiliation(s)
- Kevin A Murray
- Laboratory for Computational Molecular Design, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland)
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1321
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Willkomm J, Muresan NM, Reisner E. Enhancing H 2 evolution performance of an immobilised cobalt catalyst by rational ligand design. Chem Sci 2015; 6:2727-2736. [PMID: 29142677 PMCID: PMC5654411 DOI: 10.1039/c4sc03946g] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 01/23/2015] [Indexed: 11/21/2022] Open
Abstract
The catalyst [CoIIIBr((DO)(DOH)(4-BnPO3H2)(2-CH2py)pn)]Br, CoP3 , has been synthesised to improve the stability and activity of cobalt catalysts immobilised on metal oxide surfaces. The CoP3 catalyst contains an equatorial diimine-dioxime ligand, (DOH)2pn = N2,N2'-propanediyl-bis(2,3-butanedione-2-imine-3-oxime), with a benzylphosphonic acid (4-BnPO3H2) group and a methylpyridine (2-CH2py) ligand covalently linked to the bridgehead of the pseudo-macrocyclic diimine-dioxime ligand. The phosphonic acid functionality provides a robust anchoring group for immobilisation on metal oxides, whereas the pyridine is coordinated to the Co ion to enhance the catalytic activity of the catalyst. Electrochemical investigations in solution confirm that CoP3 shows electrocatalytic activity for the reduction of aqueous protons between pH 3 and 7. The metal oxide anchor provides the catalyst with a high affinity for mesostructured Sn-doped In2O3 electrodes (mesoITO; loading of approximately 22 nmol cm-2) and the electrostability of the attached CoP3 was confirmed by cyclic voltammetry. Finally, immobilisation of the catalyst on ruthenium-dye sensitised TiO2 nanoparticles in aqueous solutions in the presence of a hole scavenger establishes the activity of the catalyst in this photocatalytic scheme. The advantages of the elaborate catalyst design in CoP3 in terms of stability and catalytic activity are shown by direct comparison with previously reported phosphonated Co catalysts. We therefore demonstrate that rational ligand design is a viable route for improving the performance of immobilised molecular catalysts.
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Affiliation(s)
- Janina Willkomm
- Christian Doppler Laboratory for Sustainable SynGas Chemistry , Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , UK . ; http://www-reisner.ch.cam.ac.uk/
| | - Nicoleta M Muresan
- Christian Doppler Laboratory for Sustainable SynGas Chemistry , Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , UK . ; http://www-reisner.ch.cam.ac.uk/
| | - Erwin Reisner
- Christian Doppler Laboratory for Sustainable SynGas Chemistry , Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , UK . ; http://www-reisner.ch.cam.ac.uk/
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1322
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Structural differences of oxidized iron–sulfur and nickel–iron cofactors in O 2 -tolerant and O 2 -sensitive hydrogenases studied by X-ray absorption spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:162-170. [DOI: 10.1016/j.bbabio.2014.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/06/2014] [Accepted: 06/16/2014] [Indexed: 11/23/2022]
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1323
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Kaliakin DS, Zaari RR, Varganov SA. Effect of H2 Binding on the Nonadiabatic Transition Probability between Singlet and Triplet States of the [NiFe]-Hydrogenase Active Site. J Phys Chem A 2015; 119:1066-73. [DOI: 10.1021/jp510522z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Danil S. Kaliakin
- Department
of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557-0216, United States
- Department
of Chemistry, Siberian Federal University, 79 Svobodnyi Prospect, Krasnoyarsk, Krasnoyarskiy kray 660041, Russia
| | - Ryan R. Zaari
- Department
of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557-0216, United States
| | - Sergey A. Varganov
- Department
of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557-0216, United States
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1324
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Hydrogens detected by subatomic resolution protein crystallography in a [NiFe] hydrogenase. Nature 2015; 520:571-4. [DOI: 10.1038/nature14110] [Citation(s) in RCA: 217] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/20/2014] [Indexed: 01/22/2023]
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1325
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X-ray crystallographic and EPR spectroscopic analysis of HydG, a maturase in [FeFe]-hydrogenase H-cluster assembly. Proc Natl Acad Sci U S A 2015; 112:1362-7. [PMID: 25605932 DOI: 10.1073/pnas.1417252112] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Hydrogenases use complex metal cofactors to catalyze the reversible formation of hydrogen. In [FeFe]-hydrogenases, the H-cluster cofactor includes a diiron subcluster containing azadithiolate, three CO, and two CN(-) ligands. During the assembly of the H cluster, the radical S-adenosyl methionine (SAM) enzyme HydG lyses the substrate tyrosine to yield the diatomic ligands. These diatomic products form an enzyme-bound Fe(CO)x(CN)y synthon that serves as a precursor for eventual H-cluster assembly. To further elucidate the mechanism of this complex reaction, we report the crystal structure and EPR analysis of HydG. At one end of the HydG (βα)8 triosephosphate isomerase (TIM) barrel, a canonical [4Fe-4S] cluster binds SAM in close proximity to the proposed tyrosine binding site. At the opposite end of the active-site cavity, the structure reveals the auxiliary Fe-S cluster in two states: one monomer contains a [4Fe-5S] cluster, and the other monomer contains a [5Fe-5S] cluster consisting of a [4Fe-4S] cubane bridged by a μ2-sulfide ion to a mononuclear Fe(2+) center. This fifth iron is held in place by a single highly conserved protein-derived ligand: histidine 265. EPR analysis confirms the presence of the [5Fe-5S] cluster, which on incubation with cyanide, undergoes loss of the labile iron to yield a [4Fe-4S] cluster. We hypothesize that the labile iron of the [5Fe-5S] cluster is the site of Fe(CO)x(CN)y synthon formation and that the limited bonding between this iron and HydG may facilitate transfer of the intact synthon to its cognate acceptor for subsequent H-cluster assembly.
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1326
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Gutiérrez-Sanz Ó, Tapia C, Marques MC, Zacarias S, Vélez M, Pereira IAC, De Lacey AL. Induction of a Proton Gradient across a Gold-Supported Biomimetic Membrane by Electroenzymatic H2Oxidation. Angew Chem Int Ed Engl 2015; 54:2684-7. [DOI: 10.1002/anie.201411182] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Indexed: 01/22/2023]
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1327
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Gutiérrez-Sanz Ó, Tapia C, Marques MC, Zacarias S, Vélez M, Pereira IAC, De Lacey AL. Induction of a Proton Gradient across a Gold-Supported Biomimetic Membrane by Electroenzymatic H2Oxidation. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201411182] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1328
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Wang X, Zhang T, Yang Q, Jiang S, Li B. Synthesis and Characterization of Bio-Inspired Diiron Complexes and Their Catalytic Activity for Direct Hydroxylation of Aromatic Compounds. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201402918] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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1329
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Tran PD, Morozan A, Archambault S, Heidkamp J, Chenevier P, Dau H, Fontecave M, Martinent A, Jousselme B, Artero V. A noble metal-free proton-exchange membrane fuel cell based on bio-inspired molecular catalysts. Chem Sci 2015; 6:2050-2053. [PMID: 29142673 PMCID: PMC5654240 DOI: 10.1039/c4sc03774j] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 01/05/2015] [Indexed: 11/21/2022] Open
Abstract
Bio-inspired chemistry allowed for the development of the first noble metal-free polymer electrolyte membrane hydrogen fuel cell (PEMFC). The device proved operational under technologically relevant conditions.
Hydrogen is a promising energy vector for storing renewable energies: obtained from water-splitting, in electrolysers or photoelectrochemical cells, it can be turned back to electricity on demand in fuel cells (FCs). Proton exchange membrane (PEM) devices with low internal resistance, high compactness and stability are an attractive technology optimized over decades, affording fast start-up times and low operating temperatures. However, they rely on the powerful catalytic properties of noble metals such as platinum, while lower cost, more abundant materials would be needed for economic viability. Replacing these noble metals at both electrodes has long proven to be a difficult task, so far incompatible with PEM technologies. Here we take advantage of newly developed bio-inspired molecular H2 oxidation catalysts and noble metal-free O2-reducing materials, to fabricate a noble metal-free PEMFC, with an 0.74 V open circuit voltage and a 23 μW cm–2 output power under technologically relevant conditions. X-ray absorption spectroscopy measurements confirm that the catalysts are stable and retain their structure during turnover.
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Affiliation(s)
- P D Tran
- Laboratoire de Chimie et Biologie des Métaux , Université Grenoble Alpes , CNRS , CEA , 17 rue des Martyrs , 38054 Grenoble Cedex 09 , France .
| | - A Morozan
- CEA Saclay , IRAMIS , NIMBE/UMR 3685 , Laboratory of Innovation in Surface Chemistry and Nanosciences (LICSEN) , Gif sur Yvette F-91191 , France
| | - S Archambault
- Institut LITEN CEA LITEN/DTNM/LCSN , Grenoble , France
| | - J Heidkamp
- FB Physik , Free University Berlin , Berlin , Germany
| | - P Chenevier
- Université Grenoble Alpes , CNRS , CEA , INAC-SPRAM , F-38000 Grenoble , France
| | - H Dau
- FB Physik , Free University Berlin , Berlin , Germany
| | - M Fontecave
- Laboratoire de Chimie et Biologie des Métaux , Université Grenoble Alpes , CNRS , CEA , 17 rue des Martyrs , 38054 Grenoble Cedex 09 , France . .,Collège de France , 11 Place Marcelin Berthelot , 75005 Paris , France
| | - A Martinent
- Institut LITEN CEA LITEN/DTNM/LCSN , Grenoble , France
| | - B Jousselme
- CEA Saclay , IRAMIS , NIMBE/UMR 3685 , Laboratory of Innovation in Surface Chemistry and Nanosciences (LICSEN) , Gif sur Yvette F-91191 , France
| | - V Artero
- Laboratoire de Chimie et Biologie des Métaux , Université Grenoble Alpes , CNRS , CEA , 17 rue des Martyrs , 38054 Grenoble Cedex 09 , France .
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1330
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Ochi N, Matsumoto T, Dei T, Nakao Y, Sato H, Tatsumi K, Sakaki S. Heterolytic activation of dihydrogen molecule by hydroxo-/sulfido-bridged ruthenium-germanium dinuclear complex. Theoretical insights. Inorg Chem 2015; 54:576-85. [PMID: 25559259 DOI: 10.1021/ic502463y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Heterolytic activation of dihydrogen molecule (H2) by hydroxo-/sulfido-bridged ruthenium-germanium dinuclear complex [Dmp(Dep)Ge(μ-S)(μ-OH)Ru(PPh3)](+) (1) (Dmp = 2,6-dimesitylphenyl, Dep = 2,6-diethylphenyl) is theoretically investigated with the ONIOM(DFT:MM) method. H2 approaches 1 to afford an intermediate [Dmp(Dep)(HO)Ge(μ-S)Ru(PPh3)](+)-(H2) (2). In 2, the Ru-OH coordinate bond is broken but H2 does not yet coordinate with the Ru center. Then, the H2 further approaches the Ru center through a transition state TS2-3 to afford a dihydrogen σ-complex [Dmp(Dep)(HO)Ge(μ-S)Ru(η(2)-H2)(PPh3)](+) (3). Starting from 3, the H-H σ-bond is cleaved by the Ru and Ge-OH moieties to form [Dmp(Dep)(H2O)Ge(μ-S)Ru(H)(PPh3)](+) (4). In 4, hydride and H2O coordinate with the Ru and Ge centers, respectively. Electron population changes clearly indicate that this H-H σ-bond cleavage occurs in a heterolytic manner like H2 activation by hydrogenase. Finally, the H2O dissociates from the Ge center to afford [Dmp(Dep)Ge(μ-S)Ru(H)(PPh3)](+) (PRD). This step is rate-determining. The activation energy of the backward reaction is moderately smaller than that of the forward reaction, which is consistent with the experimental result that PRD reacts with H2O to form 1 and H2. In the Si analogue [Dmp(Dep)Si(μ-S)(μ-OH)Ru(PPh3)](+) (1Si), the isomerization of 1Si to 2Si easily occurs with a small activation energy, while the dissociation of H2O from the Si center needs a considerably large activation energy. Based on these computational findings, it is emphasized that the reaction of 1 resembles well that of hydrogenase and the use of Ge in 1 is crucial for this heterolytic H-H σ-bond activation.
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Affiliation(s)
- Noriaki Ochi
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 610-8510, Japan
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1331
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Steinbeck J, Nikolova D, Weingarten R, Johnson X, Richaud P, Peltier G, Hermann M, Magneschi L, Hippler M. Deletion of Proton Gradient Regulation 5 (PGR5) and PGR5-Like 1 (PGRL1) proteins promote sustainable light-driven hydrogen production in Chlamydomonas reinhardtii due to increased PSII activity under sulfur deprivation. FRONTIERS IN PLANT SCIENCE 2015; 6:892. [PMID: 26579146 PMCID: PMC4621405 DOI: 10.3389/fpls.2015.00892] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/07/2015] [Indexed: 05/19/2023]
Abstract
Continuous hydrogen photo-production under sulfur deprivation was studied in the Chlamydomonas reinhardtii pgr5 pgrl1 double mutant and respective single mutants. Under medium light conditions, the pgr5 exhibited the highest performance and produced about eight times more hydrogen than the wild type, making pgr5 one of the most efficient hydrogen producer reported so far. The pgr5 pgrl1 double mutant showed an increased hydrogen burst at the beginning of sulfur deprivation under high light conditions, but in this case the overall amount of hydrogen produced by pgr5 pgrl1 as well as pgr5 was diminished due to photo-inhibition and increased degradation of PSI. In contrast, the pgrl1 was effective in hydrogen production in both high and low light. Blocking photosynthetic electron transfer by DCMU stopped hydrogen production almost completely in the mutant strains, indicating that the main pathway of electrons toward enhanced hydrogen production is via linear electron transport. Indeed, PSII remained more active and stable in the pgr mutant strains as compared to the wild type. Since transition to anaerobiosis was faster and could be maintained due to an increased oxygen consumption capacity, this likely preserves PSII from photo-oxidative damage in the pgr mutants. Hence, we conclude that increased hydrogen production under sulfur deprivation in the pgr5 and pgrl1 mutants is caused by an increased stability of PSII permitting sustainable light-driven hydrogen production in Chlamydomonas reinhardtii.
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Affiliation(s)
- Janina Steinbeck
- Institute of Plant Biology and Biotechnology, University of MünsterMünster, Germany
| | - Denitsa Nikolova
- Institute of Plant Biology and Biotechnology, University of MünsterMünster, Germany
| | - Robert Weingarten
- Institute of Plant Biology and Biotechnology, University of MünsterMünster, Germany
| | - Xenie Johnson
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Institut de Biologie Environnementale et de Biotechnologie, Direction des Sciences du Vivant, Commissariat à l’Energie Atomique et aux Energies AlternativesSaint-Paul-lez-Durance, France
- CNRS, UMR 7265, Biologie Végétale et Microbiologie EnvironnementaleSaint-Paul-lez-Durance, France
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Aix Marseille UniversitéSaint-Paul-lez-Durance, France
| | - Pierre Richaud
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Institut de Biologie Environnementale et de Biotechnologie, Direction des Sciences du Vivant, Commissariat à l’Energie Atomique et aux Energies AlternativesSaint-Paul-lez-Durance, France
- CNRS, UMR 7265, Biologie Végétale et Microbiologie EnvironnementaleSaint-Paul-lez-Durance, France
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Aix Marseille UniversitéSaint-Paul-lez-Durance, France
| | - Gilles Peltier
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Institut de Biologie Environnementale et de Biotechnologie, Direction des Sciences du Vivant, Commissariat à l’Energie Atomique et aux Energies AlternativesSaint-Paul-lez-Durance, France
- CNRS, UMR 7265, Biologie Végétale et Microbiologie EnvironnementaleSaint-Paul-lez-Durance, France
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Aix Marseille UniversitéSaint-Paul-lez-Durance, France
| | - Marita Hermann
- Institute of Plant Biology and Biotechnology, University of MünsterMünster, Germany
| | - Leonardo Magneschi
- Institute of Plant Biology and Biotechnology, University of MünsterMünster, Germany
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of MünsterMünster, Germany
- *Correspondence: Michael Hippler,
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1332
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Musiani F, Zambelli B, Bazzani M, Mazzei L, Ciurli S. Nickel-responsive transcriptional regulators. Metallomics 2015; 7:1305-18. [DOI: 10.1039/c5mt00072f] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The structural features, metal coordination modes and metal binding thermodynamics of known Ni(ii)-dependent transcriptional regulators are highlighted and discussed.
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Affiliation(s)
- Francesco Musiani
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Micaela Bazzani
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Luca Mazzei
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
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1333
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Taketa M, Nakagawa H, Habukawa M, Osuka H, Kihira K, Komori H, Shibata N, Ishii M, Igarashi Y, Nishihara H, Yoon KS, Ogo S, Shomura Y, Higuchi Y. Crystallization and preliminary X-ray analysis of the NAD+-reducing [NiFe] hydrogenase from Hydrogenophilus thermoluteolus TH-1. Acta Crystallogr F Struct Biol Commun 2015; 71:96-9. [PMID: 25615977 PMCID: PMC4304756 DOI: 10.1107/s2053230x14026521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/02/2014] [Indexed: 11/10/2022] Open
Abstract
NAD+-reducing [NiFe] hydrogenases catalyze the oxidoreduction of dihydrogen concomitant with the interconversion of NAD+ and NADH. Here, the isolation, purification and crystallization of the NAD+-reducing [NiFe] hydrogenase from Hydrogenophilus thermoluteolus TH-1 are reported. Crystals of the NAD+-reducing [NiFe] hydrogenase were obtained within one week from a solution containing polyethylene glycol using the sitting-drop vapour-diffusion method and micro-seeding. The crystal diffracted to 2.58 Å resolution and belonged to space group C2, with unit-cell parameters a=131.43, b=189.71, c=124.59 Å, β=109.42°. Assuming the presence of two NAD+-reducing [NiFe] hydrogenase molecules in the asymmetric unit, VM was calculated to be 2.2 Å3 Da(-1), which corresponds to a solvent content of 43%. Initial phases were determined by the single-wavelength anomalous dispersion method using the anomalous signal from the Fe atoms.
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Affiliation(s)
- Midori Taketa
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan and Science Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Hanae Nakagawa
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Mao Habukawa
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Hisao Osuka
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Kiyohito Kihira
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Hirofumi Komori
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
- SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Naoki Shibata
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
- SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Masaharu Ishii
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yasuo Igarashi
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hirofumi Nishihara
- Department of Bioresource Science, Ibaraki University, 3-21-1 Chu-ou, Ami, Ibaraki 300-0393, Japan
| | - Ki-Seok Yoon
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Seiji Ogo
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Chemistry and Biochemistry, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yasuhito Shomura
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
- SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Yoshiki Higuchi
- Department of Picobiology, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan and Science Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
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1334
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Tooley CA, Pazicni S, Berda EB. Toward a tunable synthetic [FeFe] hydrogenase mimic: single-chain nanoparticles functionalized with a single diiron cluster. Polym Chem 2015. [DOI: 10.1039/c5py01196e] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report two novel “clickable” [(μ-S2C2H4NR)Fe2(CO)6] complexes and their incorporation into single-chain nanoparticles.
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Affiliation(s)
- C. A. Tooley
- University of New Hampshire
- Department of Chemistry
- Durham
- USA
| | - S. Pazicni
- University of New Hampshire
- Department of Chemistry
- Durham
- USA
| | - E. B. Berda
- University of New Hampshire
- Department of Chemistry
- Durham
- USA
- University of New Hampshire
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1335
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Santo K, Hirotsu M, Kinoshita I. Formation, reactivity and redox properties of carbon- and sulfur-bridged diiron complexes derived from dibenzothienyl Schiff bases: effect of N,N- and N,P-chelating moieties. Dalton Trans 2015; 44:4155-66. [DOI: 10.1039/c4dt03422h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Redox properties of C,S-bridged diiron complexes were controlled by using dibenzothienyl Schiff base precursors with an N,N- or N,P-chelating moiety.
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Affiliation(s)
- Kiyokazu Santo
- Division of Molecular Materials Science
- Graduate School of Science
- Osaka City University
- Sumiyoshi-ku
- Japan
| | - Masakazu Hirotsu
- Division of Molecular Materials Science
- Graduate School of Science
- Osaka City University
- Sumiyoshi-ku
- Japan
| | - Isamu Kinoshita
- Division of Molecular Materials Science
- Graduate School of Science
- Osaka City University
- Sumiyoshi-ku
- Japan
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1336
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Lonsdale TH, Lauterbach L, Honda Malca S, Nestl BM, Hauer B, Lenz O. H2-driven biotransformation of n-octane to 1-octanol by a recombinant Pseudomonas putida strain co-synthesizing an O2-tolerant hydrogenase and a P450 monooxygenase. Chem Commun (Camb) 2015; 51:16173-5. [DOI: 10.1039/c5cc06078h] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A bacterial whole-cell system was designed for hydroxylation of n-octane to 1-octanol at the expense of molecular hydrogen and oxygen.
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Affiliation(s)
- Thomas H. Lonsdale
- Department of Chemistry
- Technische Universität Berlin
- 10623 Berlin
- Germany
- Department of Chemistry
| | - Lars Lauterbach
- Department of Chemistry
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Sumire Honda Malca
- Institute of Technical Biochemistry
- Universität Stuttgart
- Stuttgart
- Germany
| | - Bettina M. Nestl
- Institute of Technical Biochemistry
- Universität Stuttgart
- Stuttgart
- Germany
| | - Bernhard Hauer
- Institute of Technical Biochemistry
- Universität Stuttgart
- Stuttgart
- Germany
| | - Oliver Lenz
- Department of Chemistry
- Technische Universität Berlin
- 10623 Berlin
- Germany
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1337
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Horch M, Hildebrandt P, Zebger I. Concepts in bio-molecular spectroscopy: vibrational case studies on metalloenzymes. Phys Chem Chem Phys 2015; 17:18222-37. [DOI: 10.1039/c5cp02447a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Challenges and chances in bio-molecular spectroscopy are exemplified by vibrational case studies on metalloenzymes.
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Affiliation(s)
- M. Horch
- Technische Universität Berlin
- Institut für Chemie
- D-10623 Berlin
- Germany
| | - P. Hildebrandt
- Technische Universität Berlin
- Institut für Chemie
- D-10623 Berlin
- Germany
| | - I. Zebger
- Technische Universität Berlin
- Institut für Chemie
- D-10623 Berlin
- Germany
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1338
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Xu L, Armstrong FA. Pushing the limits for enzyme-based membrane-less hydrogen fuel cells – achieving useful power and stability. RSC Adv 2015. [DOI: 10.1039/c4ra13565b] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The festive Hydrogen House, powered by a hydrogen–air mixture using an enzyme fuel cell.
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Affiliation(s)
- Lang Xu
- Inorganic Chemistry Laboratory
- Department of Chemistry
- University of Oxford
- Oxford OX1 3QR
- UK
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory
- Department of Chemistry
- University of Oxford
- Oxford OX1 3QR
- UK
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1339
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Kukunuri S, Krishnan MR, Sampath S. The effect of structural dimensionality on the electrocatalytic properties of the nickel selenide phase. Phys Chem Chem Phys 2015; 17:23448-59. [DOI: 10.1039/c5cp03900b] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Synthesis of different morphologies of nickel selenide structures and their activities in various applications.
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Affiliation(s)
- Suresh Kukunuri
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore 560012
- India
| | - M. Reshma Krishnan
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore 560012
- India
| | - S. Sampath
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore 560012
- India
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1340
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Almazahreh LR, Imhof W, Talarmin J, Schollhammer P, Görls H, El-khateeb M, Weigand W. Ligand effects on the electrochemical behavior of [Fe2(CO)5(L){μ-(SCH2)2(Ph)PO}] (L = PPh3, P(OEt)3) hydrogenase model complexes. Dalton Trans 2015; 44:7177-89. [DOI: 10.1039/c5dt00064e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this paper we study the influence of substituting one CO ligand in [Fe2(CO)6{μ-(SCH2)2(Ph)PO}] (1) by better σ-donors (PPh3(2) and P(OMe)3(3)) in relation to the electrochemical behavior.
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Affiliation(s)
- Laith R. Almazahreh
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- D-07743 Jena
- Germany
| | - Wolfgang Imhof
- Institut für Integrierte Naturwissenschaften
- Universität Koblenz-Landau
- D-56070 Koblenz
- Germany
| | - Jean Talarmin
- UMR CNRS 6521
- Université de Bretagne Occidentale
- 29238 Brest-Cedex
- France
| | | | - Helmar Görls
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- D-07743 Jena
- Germany
| | - Mohammad El-khateeb
- Chemistry Department
- Jordan University of Science and Technology
- 22110 Irbid
- Jordan
| | - Wolfgang Weigand
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- D-07743 Jena
- Germany
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1341
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Perotto CU, Marshall G, Jones GJ, Stephen Davies E, Lewis W, McMaster J, Schröder M. A Ni(i)Fe(ii) analogue of the Ni-L state of the active site of the [NiFe] hydrogenases. Chem Commun (Camb) 2015; 51:16988-91. [DOI: 10.1039/c5cc05881c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
[Ni(L1)Fe(tBuNC)4]+ is an unprecedented Ni(i)Fe(ii) species that reproduces the electronic configuration of the Ni-L state of the [NiFe] hydrogenases.
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Affiliation(s)
| | | | | | | | | | | | - Martin Schröder
- The University of Nottingham
- Nottingham
- UK
- The University of Manchester
- Manchester
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1342
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Gan L, Jennings D, Laureanti J, Jones AK. Biomimetic Complexes for Production of Dihydrogen and Reduction of CO2. TOP ORGANOMETAL CHEM 2015. [DOI: 10.1007/3418_2015_146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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1343
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Cox N, Nalepa A, Pandelia ME, Lubitz W, Savitsky A. Pulse Double-Resonance EPR Techniques for the Study of Metallobiomolecules. Methods Enzymol 2015; 563:211-49. [DOI: 10.1016/bs.mie.2015.08.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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1344
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Dance I. Protonation of bridging sulfur in cubanoid Fe4S4 clusters causes large geometric changes: the theory of geometric and electronic structure. Dalton Trans 2015; 44:4707-17. [DOI: 10.1039/c4dt03681f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Density functional calculations indicate that protonation of a μ3-S atom in cubanoid clusters [Fe4S4X4]2− leads to a large extension of one Fe–S(H) bond such that the SH ligand is doubly-bridging, μ-SH.
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Affiliation(s)
- Ian Dance
- School of Chemistry
- University of New South Wales
- Sydney 2052
- Australia
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1345
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Trautwein R, Almazahreh LR, Görls H, Weigand W. Steric effect of the dithiolato linker on the reduction mechanism of [Fe2(CO)6{μ-(XCH2)2CRR′}] hydrogenase models (X = S, Se). Dalton Trans 2015; 44:18780-94. [DOI: 10.1039/c5dt01387a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Investigations of the electrochemical properties of [Fe2(CO)6{μ-(XCH2)2CRR′}] (X = S, Se; R or R′ = H or Me) showed that the complex with the bulkiest CMe2moiety undergoes reduction with potential inversion.
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Affiliation(s)
- Ralf Trautwein
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- D-07743 Jena
- Germany
| | - Laith R. Almazahreh
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- D-07743 Jena
- Germany
| | - Helmar Görls
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- D-07743 Jena
- Germany
| | - Wolfgang Weigand
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- D-07743 Jena
- Germany
- Jena Center of Soft Matter (JCSM)
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1346
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Sode O, Voth GA. Electron transfer activation of a second water channel for proton transport in [FeFe]-hydrogenase. J Chem Phys 2014; 141:22D527. [DOI: 10.1063/1.4902236] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Olaseni Sode
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, The University of Chicago, Chicago, Illinois 60637, USA and Computing, Environment and Life Sciences, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Gregory A. Voth
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, The University of Chicago, Chicago, Illinois 60637, USA and Computing, Environment and Life Sciences, Argonne National Laboratory, Argonne, Illinois 60439, USA
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1347
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Chouffai D, Capon JF, De Gioia L, Pétillon FY, Schollhammer P, Talarmin J, Zampella G. A Diferrous Dithiolate as a Model of the Elusive Hoxinact State of the [FeFe] Hydrogenases: An Electrochemical and Theoretical Dissection of Its Redox Chemistry. Inorg Chem 2014; 54:299-311. [DOI: 10.1021/ic5024746] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Dounia Chouffai
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires
et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, CS 93837, 29238 Brest-Cedex 3, France
| | - Jean-François Capon
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires
et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, CS 93837, 29238 Brest-Cedex 3, France
| | - Luca De Gioia
- Department
of Biotechnology and Bioscience, University of Milano-Bicocca, Piazza
della Scienza 2, 20126 Milan, Italy
| | - François Y. Pétillon
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires
et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, CS 93837, 29238 Brest-Cedex 3, France
| | - Philippe Schollhammer
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires
et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, CS 93837, 29238 Brest-Cedex 3, France
| | - Jean Talarmin
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires
et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, CS 93837, 29238 Brest-Cedex 3, France
| | - Giuseppe Zampella
- Department
of Biotechnology and Bioscience, University of Milano-Bicocca, Piazza
della Scienza 2, 20126 Milan, Italy
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1348
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Dance I. What is the trigger mechanism for the reversal of electron flow in oxygen-tolerant [NiFe] hydrogenases? Chem Sci 2014; 6:1433-1443. [PMID: 29560232 PMCID: PMC5811149 DOI: 10.1039/c4sc03223c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/08/2014] [Indexed: 11/21/2022] Open
Abstract
A new mechanistic model is developed for the sequence of events by which oxygen-tolerant [NiFe] hydrogenase enzymes respond to O2.
The [NiFe] hydrogenases use an electron transfer relay of three FeS clusters – proximal, medial and distal – to release the electrons from the principal reaction, H2 → 2H+ + 2e–, that occurs at the Ni–Fe catalytic site. This site is normally inactivated by O2, but the subclass of O2-tolerant [NiFe] hydrogenases are able to counter this inactivation through the agency of an unusual and unprecedented proximal cluster, with composition [Fe4S3(Scys)6], that is able to transfer two electrons back to the Ni–Fe site and effect crucial reduction of O2-derived species and thereby reactivate the Ni–Fe site. This proximal cluster gates both the direction and the number of electrons flowing through it, and can reverse the normal flow during O2 attack. The unusual structures and redox potentials of the proximal cluster are known: a structural change in the proximal cluster causes changes in its electron-transfer potentials. Using protein structure analysis and density functional simulations, this paper identifies a closed protonic system comprising the proximal cluster, some contiguous residues, and a proton reservoir, and proposes that it is activated by O2-induced conformational change at the Ni–Fe site. This change is linked to a key histidine residue which then causes protonation of the proximal cluster, and migration of this proton to a key μ3-S atom. The resulting SH group causes the required structural change at the proximal cluster, modifying its redox potentials, and leads to the reversed electron flow back to the Ni–Fe site. This cycle is reversible, and the protons involved are independent of those used or produced in reactions at the active site. Existing experimental support for this model is cited, and new testing experiments are suggested.
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Affiliation(s)
- Ian Dance
- School of Chemistry , University of New South Wales , Sydney 2052 , Australia .
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1349
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Salvadori E, Fung MW, Hoffmann M, Anderson HL, Kay CWM. Exploiting the Symmetry of the Resonator Mode to Enhance PELDOR Sensitivity. APPLIED MAGNETIC RESONANCE 2014; 46:359-368. [PMID: 25798030 PMCID: PMC4359710 DOI: 10.1007/s00723-014-0621-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 10/29/2014] [Indexed: 06/04/2023]
Abstract
Pulsed electron paramagnetic resonance (EPR) spectroscopy using microwaves at two frequencies can be employed to measure distances between pairs of paramagnets separated by up to 10 nm. The method, combined with site-directed mutagenesis, has become increasingly popular in structural biology for both its selectivity and capability of providing information not accessible through more standard methods such as nuclear magnetic resonance and X-ray crystallography. Despite these advantages, EPR distance measurements suffer from poor sensitivity. One contributing factor is technical: since 65 MHz typically separates the pump and detection frequencies, they cannot both be located at the center of the pseudo-Lorentzian microwave resonance of a single-mode resonator. To maximize the inversion efficiency, the pump pulse is usually placed at the center of the resonance, while the observer frequency is placed in the wing, with consequent reduction in sensitivity. Here, we consider an alternative configuration: by spacing pump and observer frequencies symmetrically with respect to the microwave resonance and by increasing the quality factor, valuable improvement in the signal-to-noise ratio can be obtained.
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Affiliation(s)
- Enrico Salvadori
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WC1H 0AH UK
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - Mei Wai Fung
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - Markus Hoffmann
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3TA UK
| | - Harry L. Anderson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3TA UK
| | - Christopher W. M. Kay
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WC1H 0AH UK
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT UK
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1350
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Bis-(diphenylphosphino)methane as Mono- or Bi-dentate Ligand of Benzoate-Functionalized Diiron Propanedithiolate Complexes: Catalysis for the Reduction of Proton. J CLUST SCI 2014. [DOI: 10.1007/s10876-014-0819-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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