1
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Sidabras JW, Stripp ST. A personal account on 25 years of scientific literature on [FeFe]-hydrogenase. J Biol Inorg Chem 2023; 28:355-378. [PMID: 36856864 DOI: 10.1007/s00775-023-01992-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 01/25/2023] [Indexed: 03/02/2023]
Abstract
[FeFe]-hydrogenases are gas-processing metalloenzymes that catalyze H2 oxidation and proton reduction (H2 release) in microorganisms. Their high turnover frequencies and lack of electrical overpotential in the hydrogen conversion reaction has inspired generations of biologists, chemists, and physicists to explore the inner workings of [FeFe]-hydrogenase. Here, we revisit 25 years of scientific literature on [FeFe]-hydrogenase and propose a personal account on 'must-read' research papers and review article that will allow interested scientists to follow the recent discussions on catalytic mechanism, O2 sensitivity, and the in vivo synthesis of the active site cofactor with its biologically uncommon ligands carbon monoxide and cyanide. Focused on-but not restricted to-structural biology and molecular biophysics, we highlight future directions that may inspire young investigators to pursue a career in the exciting and competitive field of [FeFe]-hydrogenase research.
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Affiliation(s)
- Jason W Sidabras
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, USA, 53226.
| | - Sven T Stripp
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
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2
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Understanding 2D-IR Spectra of Hydrogenases: A Descriptive and Predictive Computational Study. Catalysts 2022. [DOI: 10.3390/catal12090988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
[NiFe] hydrogenases are metalloenzymes that catalyze the reversible cleavage of dihydrogen (), a clean future fuel. Understanding the mechanism of these biocatalysts requires spectroscopic techniques that yield insights into the structure and dynamics of the [NiFe] active site. Due to the presence of CO and ligands at this cofactor, infrared (IR) spectroscopy represents an ideal technique for studying these aspects, but molecular information from linear IR absorption experiments is limited. More detailed insights can be obtained from ultrafast nonlinear IR techniques like IRpump−IRprobe and two-dimensional (2D-)IR spectroscopy. However, fully exploiting these advanced techniques requires an in-depth understanding of experimental observables and the encoded molecular information. To address this challenge, we present a descriptive and predictive computational approach for the simulation and analysis of static 2D-IR spectra of [NiFe] hydrogenases and similar organometallic systems. Accurate reproduction of experimental spectra from a first-coordination-sphere model suggests a decisive role of the [NiFe] core in shaping the enzymatic potential energy surface. We also reveal spectrally encoded molecular information that is not accessible by experiments, thereby helping to understand the catalytic role of the diatomic ligands, structural differences between [NiFe] intermediates, and possible energy transfer mechanisms. Our studies demonstrate the feasibility and benefits of computational spectroscopy in the 2D-IR investigation of hydrogenases, thereby further strengthening the potential of this nonlinear IR technique as a powerful research tool for the investigation of complex bioinorganic molecules.
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3
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Stripp ST, Duffus BR, Fourmond V, Léger C, Leimkühler S, Hirota S, Hu Y, Jasniewski A, Ogata H, Ribbe MW. Second and Outer Coordination Sphere Effects in Nitrogenase, Hydrogenase, Formate Dehydrogenase, and CO Dehydrogenase. Chem Rev 2022; 122:11900-11973. [PMID: 35849738 PMCID: PMC9549741 DOI: 10.1021/acs.chemrev.1c00914] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Gases like H2, N2, CO2, and CO are increasingly recognized as critical feedstock in "green" energy conversion and as sources of nitrogen and carbon for the agricultural and chemical sectors. However, the industrial transformation of N2, CO2, and CO and the production of H2 require significant energy input, which renders processes like steam reforming and the Haber-Bosch reaction economically and environmentally unviable. Nature, on the other hand, performs similar tasks efficiently at ambient temperature and pressure, exploiting gas-processing metalloenzymes (GPMs) that bind low-valent metal cofactors based on iron, nickel, molybdenum, tungsten, and sulfur. Such systems are studied to understand the biocatalytic principles of gas conversion including N2 fixation by nitrogenase and H2 production by hydrogenase as well as CO2 and CO conversion by formate dehydrogenase, carbon monoxide dehydrogenase, and nitrogenase. In this review, we emphasize the importance of the cofactor/protein interface, discussing how second and outer coordination sphere effects determine, modulate, and optimize the catalytic activity of GPMs. These may comprise ionic interactions in the second coordination sphere that shape the electron density distribution across the cofactor, hydrogen bonding changes, and allosteric effects. In the outer coordination sphere, proton transfer and electron transfer are discussed, alongside the role of hydrophobic substrate channels and protein structural changes. Combining the information gained from structural biology, enzyme kinetics, and various spectroscopic techniques, we aim toward a comprehensive understanding of catalysis beyond the first coordination sphere.
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Affiliation(s)
- Sven T Stripp
- Freie Universität Berlin, Experimental Molecular Biophysics, Berlin 14195, Germany
| | | | - Vincent Fourmond
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Christophe Léger
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Silke Leimkühler
- University of Potsdam, Molecular Enzymology, Potsdam 14476, Germany
| | - Shun Hirota
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan
| | - Yilin Hu
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Andrew Jasniewski
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Hideaki Ogata
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan.,Hokkaido University, Institute of Low Temperature Science, Sapporo 060-0819, Japan.,Graduate School of Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Markus W Ribbe
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States.,Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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4
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Birrell JA, Rodríguez-Maciá P, Reijerse EJ, Martini MA, Lubitz W. The catalytic cycle of [FeFe] hydrogenase: A tale of two sites. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214191] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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5
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Affiliation(s)
- Brandon L. Greene
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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6
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Horch M, Schoknecht J, Wrathall SLD, Greetham GM, Lenz O, Hunt NT. Understanding the structure and dynamics of hydrogenases by ultrafast and two-dimensional infrared spectroscopy. Chem Sci 2019; 10:8981-8989. [PMID: 31762978 PMCID: PMC6857670 DOI: 10.1039/c9sc02851j] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 08/05/2019] [Indexed: 11/21/2022] Open
Abstract
Hydrogenases are valuable model enzymes for sustainable energy conversion approaches using H2, but rational utilization of these base-metal biocatalysts requires a detailed understanding of the structure and dynamics of their complex active sites. The intrinsic CO and CN- ligands of these metalloenzymes represent ideal chromophores for infrared (IR) spectroscopy, but structural and dynamic insight from conventional IR absorption experiments is limited. Here, we apply ultrafast and two-dimensional (2D) IR spectroscopic techniques, for the first time, to study hydrogenases in detail. Using an O2-tolerant [NiFe] hydrogenase as a model system, we demonstrate that IR pump-probe spectroscopy can explore catalytically relevant ligand bonding by accessing high-lying vibrational states. This ultrafast technique also shows that the protein matrix is influential in vibrational relaxation, which may be relevant for energy dissipation from the active site during fast reaction steps. Further insights into the relevance of the active site environment are provided by 2D-IR spectroscopy, which reveals equilibrium dynamics and structural constraints imposed on the H2-accepting intermediate of [NiFe] hydrogenases. Both techniques offer new strategies for uniquely identifying redox-structural states in complex catalytic mixtures via vibrational quantum beats and 2D-IR off-diagonal peaks. Together, these findings considerably expand the scope of IR spectroscopy in hydrogenase research, and new perspectives for the characterization of these enzymes and other (bio-)organometallic targets are presented.
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Affiliation(s)
- Marius Horch
- Department of Chemistry , York Biomedical Research Institute , University of York , Heslington , York , YO10 5DD , UK .
- Institut für Chemie , Technische Universität Berlin , Straße des 17. Juni 135 , Berlin , D-10623 , Germany
| | - Janna Schoknecht
- Institut für Chemie , Technische Universität Berlin , Straße des 17. Juni 135 , Berlin , D-10623 , Germany
| | - Solomon L D Wrathall
- Department of Chemistry , York Biomedical Research Institute , University of York , Heslington , York , YO10 5DD , UK .
| | - Gregory M Greetham
- STFC Central Laser Facility, Research Complex at Harwell , Rutherford Appleton Laboratory , Harwell Science and Innovation Campus , Didcot , Oxford , OX110PE , UK
| | - Oliver Lenz
- Institut für Chemie , Technische Universität Berlin , Straße des 17. Juni 135 , Berlin , D-10623 , Germany
| | - Neil T Hunt
- Department of Chemistry , York Biomedical Research Institute , University of York , Heslington , York , YO10 5DD , UK .
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7
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Baffert C, Kpebe A, Avilan L, Brugna M. Hydrogenases and H 2 metabolism in sulfate-reducing bacteria of the Desulfovibrio genus. Adv Microb Physiol 2019; 74:143-189. [PMID: 31126530 DOI: 10.1016/bs.ampbs.2019.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Hydrogen metabolism plays a central role in sulfate-reducing bacteria of the Desulfovibrio genus and is based on hydrogenases that catalyze the reversible conversion of protons into dihydrogen. These metabolically versatile microorganisms possess a complex hydrogenase system composed of several enzymes of both [FeFe]- and [NiFe]-type that can vary considerably from one Desulfovibrio species to another. This review covers the molecular and physiological aspects of hydrogenases and H2 metabolism in Desulfovibrio but focuses particularly on our model bacterium Desulfovibrio fructosovorans. The search of hydrogenase genes in more than 30 sequenced genomes provides an overview of the distribution of these enzymes in Desulfovibrio. Our discussion will consider the significance of the involvement of electron-bifurcation in H2 metabolism.
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Affiliation(s)
- Carole Baffert
- Aix-Marseille University, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Arlette Kpebe
- Aix-Marseille University, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Luisana Avilan
- Aix-Marseille University, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Myriam Brugna
- Aix-Marseille University, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille, France
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8
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Infrared Characterization of the Bidirectional Oxygen-Sensitive [NiFe]-Hydrogenase from E. coli. Catalysts 2018. [DOI: 10.3390/catal8110530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
[NiFe]-hydrogenases are gas-processing metalloenzymes that catalyze the conversion of dihydrogen (H2) to protons and electrons in a broad range of microorganisms. Within the framework of green chemistry, the molecular proceedings of biological hydrogen turnover inspired the design of novel catalytic compounds for H2 generation. The bidirectional “O2-sensitive” [NiFe]-hydrogenase from Escherichia coli HYD-2 has recently been crystallized; however, a systematic infrared characterization in the presence of natural reactants is not available yet. In this study, we analyze HYD-2 from E. coli by in situ attenuated total reflection Fourier-transform infrared spectroscopy (ATR FTIR) under quantitative gas control. We provide an experimental assignment of all catalytically relevant redox intermediates alongside the O2- and CO-inhibited cofactor species. Furthermore, the reactivity and mutual competition between H2, O2, and CO was probed in real time, which lays the foundation for a comparison with other enzymes, e.g., “O2-tolerant” [NiFe]-hydrogenases. Surprisingly, only Ni-B was observed in the presence of O2 with no indications for the “unready” Ni-A state. The presented work proves the capabilities of in situ ATR FTIR spectroscopy as an efficient and powerful technique for the analysis of biological macromolecules and enzymatic small molecule catalysis.
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Abstract
Numerous recent developments in the biochemistry, molecular biology, and physiology of formate and H2 metabolism and of the [NiFe]-hydrogenase (Hyd) cofactor biosynthetic machinery are highlighted. Formate export and import by the aquaporin-like pentameric formate channel FocA is governed by interaction with pyruvate formate-lyase, the enzyme that generates formate. Formate is disproportionated by the reversible formate hydrogenlyase (FHL) complex, which has been isolated, allowing biochemical dissection of evolutionary parallels with complex I of the respiratory chain. A recently identified sulfido-ligand attached to Mo in the active site of formate dehydrogenases led to the proposal of a modified catalytic mechanism. Structural analysis of the homologous, H2-oxidizing Hyd-1 and Hyd-5 identified a novel proximal [4Fe-3S] cluster in the small subunit involved in conferring oxygen tolerance to the enzymes. Synthesis of Salmonella Typhimurium Hyd-5 occurs aerobically, which is novel for an enterobacterial Hyd. The O2-sensitive Hyd-2 enzyme has been shown to be reversible: it presumably acts as a conformational proton pump in the H2-oxidizing mode and is capable of coupling reverse electron transport to drive H2 release. The structural characterization of all the Hyp maturation proteins has given new impulse to studies on the biosynthesis of the Fe(CN)2CO moiety of the [NiFe] cofactor. It is synthesized on a Hyp-scaffold complex, mainly comprising HypC and HypD, before insertion into the apo-large subunit. Finally, clear evidence now exists indicating that Escherichia coli can mature Hyd enzymes differentially, depending on metal ion availability and the prevailing metabolic state. Notably, Hyd-3 of the FHL complex takes precedence over the H2-oxidizing enzymes.
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Greene BL, Schut GJ, Adams MWW, Dyer RB. Pre-Steady-State Kinetics of Catalytic Intermediates of an [FeFe]-Hydrogenase. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03276] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Brandon L. Greene
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Gerrit J. Schut
- Department
of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Michael W. W. Adams
- Department
of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - R. Brian Dyer
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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11
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Unification of [FeFe]-hydrogenases into three structural and functional groups. Biochim Biophys Acta Gen Subj 2016; 1860:1910-21. [DOI: 10.1016/j.bbagen.2016.05.034] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/20/2016] [Accepted: 05/26/2016] [Indexed: 11/22/2022]
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12
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Birrell JA, Wrede K, Pawlak K, Rodriguez-Maciá P, Rüdiger O, Reijerse EJ, Lubitz W. Artificial Maturation of the Highly Active Heterodimeric [FeFe] Hydrogenase from Desulfovibrio desulfuricans
ATCC 7757. Isr J Chem 2016. [DOI: 10.1002/ijch.201600035] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- James A. Birrell
- Max Planck Institute for Chemical Energy Conversion; Stiftstraße 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Kathrin Wrede
- Max Planck Institute for Chemical Energy Conversion; Stiftstraße 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Krzysztof Pawlak
- Max Planck Institute for Chemical Energy Conversion; Stiftstraße 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Patricia Rodriguez-Maciá
- Max Planck Institute for Chemical Energy Conversion; Stiftstraße 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Olaf Rüdiger
- Max Planck Institute for Chemical Energy Conversion; Stiftstraße 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Edward J. Reijerse
- Max Planck Institute for Chemical Energy Conversion; Stiftstraße 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion; Stiftstraße 34-36 D-45470 Mülheim an der Ruhr Germany
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13
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Stepwise isotope editing of [FeFe]-hydrogenases exposes cofactor dynamics. Proc Natl Acad Sci U S A 2016; 113:8454-9. [PMID: 27432985 DOI: 10.1073/pnas.1606178113] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The six-iron cofactor of [FeFe]-hydrogenases (H-cluster) is the most efficient H2-forming catalyst in nature. It comprises a diiron active site with three carbon monoxide (CO) and two cyanide (CN(-)) ligands in the active oxidized state (Hox) and one additional CO ligand in the inhibited state (Hox-CO). The diatomic ligands are sensitive reporter groups for structural changes of the cofactor. Their vibrational dynamics were monitored by real-time attenuated total reflection Fourier-transform infrared spectroscopy. Combination of (13)CO gas exposure, blue or red light irradiation, and controlled hydration of three different [FeFe]-hydrogenase proteins produced 8 Hox and 16 Hox-CO species with all possible isotopic exchange patterns. Extensive density functional theory calculations revealed the vibrational mode couplings of the carbonyl ligands and uniquely assigned each infrared spectrum to a specific labeling pattern. For Hox-CO, agreement between experimental and calculated infrared frequencies improved by up to one order of magnitude for an apical CN(-) at the distal iron ion of the cofactor as opposed to an apical CO. For Hox, two equally probable isomers with partially rotated ligands were suggested. Interconversion between these structures implies dynamic ligand reorientation at the H-cluster. Our experimental protocol for site-selective (13)CO isotope editing combined with computational species assignment opens new perspectives for characterization of functional intermediates in the catalytic cycle.
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Caserta G, Adamska-Venkatesh A, Pecqueur L, Atta M, Artero V, Roy S, Reijerse E, Lubitz W, Fontecave M. Chemical assembly of multiple metal cofactors: The heterologously expressed multidomain [FeFe]-hydrogenase from Megasphaera elsdenii. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1734-1740. [PMID: 27421233 DOI: 10.1016/j.bbabio.2016.07.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/03/2016] [Accepted: 07/10/2016] [Indexed: 10/21/2022]
Abstract
[FeFe]-hydrogenases are unique and fascinating enzymes catalyzing the reversible reduction of protons into hydrogen. These metalloenzymes display extremely large catalytic reaction rates at very low overpotential values and are, therefore, studied as potential catalysts for bioelectrodes of electrolyzers and fuel cells. Since they contain multiple metal cofactors whose biosynthesis depends on complex protein machineries, their preparation is difficult. As a consequence still few have been purified to homogeneity allowing spectroscopic and structural characterization. As part of a program aiming at getting easy access to new hydrogenases we report here a methodology based on a purely chemical assembly of their metal cofactors. This methodology is applied to the preparation and characterization of the hydrogenase from the fermentative anaerobic rumen bacterium Megasphaera elsdenii, which has only been incompletely characterized in the past.
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Affiliation(s)
- Giorgio Caserta
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Université Pierre et Marie Curie, CNRS UMR 8229, 11 place Marcelin Berthelot, 75005 Paris, France
| | | | - Ludovic Pecqueur
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Université Pierre et Marie Curie, CNRS UMR 8229, 11 place Marcelin Berthelot, 75005 Paris, France
| | - Mohamed Atta
- Laboratoire de Chimie et Biologie des Métaux, Université Grenoble Alpes, CEA/BIG, CNRS, 17 rue des martyrs, 38000 Grenoble, France
| | - Vincent Artero
- Laboratoire de Chimie et Biologie des Métaux, Université Grenoble Alpes, CEA/BIG, CNRS, 17 rue des martyrs, 38000 Grenoble, France
| | - Souvik Roy
- Laboratoire de Chimie et Biologie des Métaux, Université Grenoble Alpes, CEA/BIG, CNRS, 17 rue des martyrs, 38000 Grenoble, France
| | - Edward Reijerse
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Wolfgang Lubitz
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Université Pierre et Marie Curie, CNRS UMR 8229, 11 place Marcelin Berthelot, 75005 Paris, France.
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15
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Suess DLM, Kuchenreuther JM, De La Paz L, Swartz JR, Britt RD. Biosynthesis of the [FeFe] Hydrogenase H Cluster: A Central Role for the Radical SAM Enzyme HydG. Inorg Chem 2016; 55:478-87. [PMID: 26703931 PMCID: PMC4780679 DOI: 10.1021/acs.inorgchem.5b02274] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hydrogenase enzymes catalyze the rapid and reversible interconversion of H2 with protons and electrons. The active site of the [FeFe] hydrogenase is the H cluster, which consists of a [4Fe-4S]H subcluster linked to an organometallic [2Fe]H subcluster. Understanding the biosynthesis and catalytic mechanism of this structurally unusual active site will aid in the development of synthetic and biological hydrogenase catalysts for applications in solar fuel generation. The [2Fe]H subcluster is synthesized and inserted by three maturase enzymes-HydE, HydF, and HydG-in a complex process that involves inorganic, organometallic, and organic radical chemistry. HydG is a member of the radical S-adenosyl-l-methionine (SAM) family of enzymes and is thought to play a prominent role in [2Fe]H subcluster biosynthesis by converting inorganic Fe(2+), l-cysteine (Cys), and l-tyrosine (Tyr) into an organometallic [(Cys)Fe(CO)2(CN)](-) intermediate that is eventually incorporated into the [2Fe]H subcluster. In this Forum Article, the mechanism of [2Fe]H subcluster biosynthesis is discussed with a focus on how this key [(Cys)Fe(CO)2(CN)](-) species is formed. Particular attention is given to the initial metallocluster composition of HydG, the modes of substrate binding (Fe(2+), Cys, Tyr, and SAM), the mechanism of SAM-mediated Tyr cleavage to CO and CN(-), and the identification of the final organometallic products of the reaction.
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Affiliation(s)
- Daniel L. M. Suess
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Jon M. Kuchenreuther
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Liliana De La Paz
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - James R. Swartz
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - R. David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
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16
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Morra S, Maurelli S, Chiesa M, Mulder DW, Ratzloff MW, Giamello E, King PW, Gilardi G, Valetti F. The effect of a C298D mutation in CaHydA [FeFe]-hydrogenase: Insights into the protein-metal cluster interaction by EPR and FTIR spectroscopic investigation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:98-106. [PMID: 26482707 DOI: 10.1016/j.bbabio.2015.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 10/01/2015] [Accepted: 10/15/2015] [Indexed: 01/17/2023]
Abstract
A conserved cysteine located in the signature motif of the catalytic center (H-cluster) of [FeFe]-hydrogenases functions in proton transfer. This residue corresponds to C298 in Clostridium acetobutylicum CaHydA. Despite the chemical and structural difference, the mutant C298D retains fast catalytic activity, while replacement with any other amino acid causes significant activity loss. Given the proximity of C298 to the H-cluster, the effect of the C298D mutation on the catalytic center was studied by continuous wave (CW) and pulse electron paramagnetic resonance (EPR) and by Fourier transform infrared (FTIR) spectroscopies. Comparison of the C298D mutant with the wild type CaHydA by CW and pulse EPR showed that the electronic structure of the center is not altered. FTIR spectroscopy confirmed that absorption peak values observed in the mutant are virtually identical to those observed in the wild type, indicating that the H-cluster is not generally affected by the mutation. Significant differences were observed only in the inhibited state Hox-CO: the vibrational modes assigned to the COexo and Fed-CO in this state are shifted to lower values in C298D, suggesting different interaction of these ligands with the protein moiety when C298 is changed to D298. More relevant to the catalytic cycle, the redox equilibrium between the Hox and Hred states is modified by the mutation, causing a prevalence of the oxidized state. This work highlights how the interactions between the protein environment and the H-cluster, a dynamic closely interconnected system, can be engineered and studied in the perspective of designing bio-inspired catalysts and mimics.
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Affiliation(s)
- Simone Morra
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy
| | - Sara Maurelli
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - Mario Chiesa
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michael W Ratzloff
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Elio Giamello
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy
| | - Francesca Valetti
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy.
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17
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Peters JW, Schut GJ, Boyd ES, Mulder DW, Shepard EM, Broderick JB, King PW, Adams MWW. [FeFe]- and [NiFe]-hydrogenase diversity, mechanism, and maturation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1350-69. [PMID: 25461840 DOI: 10.1016/j.bbamcr.2014.11.021] [Citation(s) in RCA: 256] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/10/2014] [Accepted: 11/16/2014] [Indexed: 11/29/2022]
Abstract
The [FeFe]- and [NiFe]-hydrogenases catalyze the formal interconversion between hydrogen and protons and electrons, possess characteristic non-protein ligands at their catalytic sites and thus share common mechanistic features. Despite the similarities between these two types of hydrogenases, they clearly have distinct evolutionary origins and likely emerged from different selective pressures. [FeFe]-hydrogenases are widely distributed in fermentative anaerobic microorganisms and likely evolved under selective pressure to couple hydrogen production to the recycling of electron carriers that accumulate during anaerobic metabolism. In contrast, many [NiFe]-hydrogenases catalyze hydrogen oxidation as part of energy metabolism and were likely key enzymes in early life and arguably represent the predecessors of modern respiratory metabolism. Although the reversible combination of protons and electrons to generate hydrogen gas is the simplest of chemical reactions, the [FeFe]- and [NiFe]-hydrogenases have distinct mechanisms and differ in the fundamental chemistry associated with proton transfer and control of electron flow that also help to define catalytic bias. A unifying feature of these enzymes is that hydrogen activation itself has been restricted to one solution involving diatomic ligands (carbon monoxide and cyanide) bound to an Fe ion. On the other hand, and quite remarkably, the biosynthetic mechanisms to produce these ligands are exclusive to each type of enzyme. Furthermore, these mechanisms represent two independent solutions to the formation of complex bioinorganic active sites for catalyzing the simplest of chemical reactions, reversible hydrogen oxidation. As such, the [FeFe]- and [NiFe]-hydrogenases are arguably the most profound case of convergent evolution. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- John W Peters
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Gerrit J Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Eric M Shepard
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Joan B Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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18
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Lambertz C, Chernev P, Klingan K, Leidel N, Sigfridsson KGV, Happe T, Haumann M. Electronic and molecular structures of the active-site H-cluster in [FeFe]-hydrogenase determined by site-selective X-ray spectroscopy and quantum chemical calculations. Chem Sci 2014. [DOI: 10.1039/c3sc52703d] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Site-selective X-ray spectroscopy discriminated the cubane and diiron units in the H-cluster of [FeFe]-hydrogenase revealing its electronic and structural configurations.
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Affiliation(s)
- Camilla Lambertz
- Institute for Biochemistry of Plants
- Department of Photobiotechnology
- Ruhr-University Bochum
- 44780 Bochum, Germany
| | - Petko Chernev
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
| | - Katharina Klingan
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
| | - Nils Leidel
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
| | | | - Thomas Happe
- Institute for Biochemistry of Plants
- Department of Photobiotechnology
- Ruhr-University Bochum
- 44780 Bochum, Germany
| | - Michael Haumann
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
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19
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Stripp ST, Soboh B, Lindenstrauss U, Braussemann M, Herzberg M, Nies DH, Sawers RG, Heberle J. HypD is the scaffold protein for Fe-(CN)2CO cofactor assembly in [NiFe]-hydrogenase maturation. Biochemistry 2013; 52:3289-96. [PMID: 23597401 DOI: 10.1021/bi400302v] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[NiFe]-hydrogenases bind a NiFe-(CN)2CO cofactor in their catalytic large subunit. The iron-sulfur protein HypD and the small accessory protein HypC play a central role in the generation of the CO and CN(-) ligands. Infrared spectroscopy identified signatures on an anaerobically isolated HypCD complex that are reminiscent of those in the hydrogenase active site, suggesting that this complex is the assembly site of the Fe-(CN)2CO moiety of the cofactor prior to its transfer to the hydrogenase large subunit. Here, we report that HypD isolated in the absence of HypC shows infrared bands at 1956 cm(-1), 2072 cm(-1), and 2092 cm(-1) that can be assigned to CO, CN(1), and CN(2), respectively, and which are indistinguishable from those observed for the HypCD complex. HypC could not be isolated with CO or CN(-) ligand contribution. Treatment of HypD with EDTA led to the concomitant loss of Fe and the CO and CN(-) signatures, while oxidation by H2O2 resulted in a positive shift of the CO and CN(-) bands by 35 cm(-1) and 20 cm(-1), respectively, indicative of the ferrous iron as an immediate ligation site for the diatomic ligands. Analysis of HypD amino acid variants identified cysteines 41, 69, and 72 to be essential for maturation of the cofactor. We propose a refined model for the ligation of Fe-(CN)2CO to HypD and the role of HypC in [NiFe]-hydrogenase maturation.
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Affiliation(s)
- Sven T Stripp
- Experimental Molecular Biophysics, Freie Universität Berlin , Arnimalle 14, 14195 Berlin, Germany
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20
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Mulder DW, Ratzloff MW, Shepard EM, Byer AS, Noone SM, Peters JW, Broderick JB, King PW. EPR and FTIR Analysis of the Mechanism of H2 Activation by [FeFe]-Hydrogenase HydA1 from Chlamydomonas reinhardtii. J Am Chem Soc 2013; 135:6921-9. [DOI: 10.1021/ja4000257] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David W. Mulder
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado
80401, United States
| | - Michael W. Ratzloff
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado
80401, United States
| | - Eric M. Shepard
- Department
of Chemistry and
Biochemistry, Montana State University,
Bozeman, Montana 59717, United States
| | - Amanda S. Byer
- Department
of Chemistry and
Biochemistry, Montana State University,
Bozeman, Montana 59717, United States
| | - Seth M. Noone
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado
80401, United States
| | - John W. Peters
- Department
of Chemistry and
Biochemistry, Montana State University,
Bozeman, Montana 59717, United States
| | - Joan B. Broderick
- Department
of Chemistry and
Biochemistry, Montana State University,
Bozeman, Montana 59717, United States
| | - Paul W. King
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado
80401, United States
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21
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Winkler M, Esselborn J, Happe T. Molecular basis of [FeFe]-hydrogenase function: an insight into the complex interplay between protein and catalytic cofactor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:974-85. [PMID: 23507618 DOI: 10.1016/j.bbabio.2013.03.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 02/21/2013] [Accepted: 03/08/2013] [Indexed: 12/20/2022]
Abstract
The precise electrochemical features of metal cofactors that convey the functions of redox enzymes are essentially determined by the specific interaction pattern between cofactor and enclosing protein environment. However, while biophysical techniques allow a detailed understanding of the features characterizing the cofactor itself, knowledge about the contribution of the protein part is much harder to obtain. [FeFe]-hydrogenases are an interesting class of enzymes that catalyze both, H2 oxidation and the reduction of protons to molecular hydrogen with significant efficiency. The active site of these proteins consists of an unusual prosthetic group (H-cluster) with six iron and six sulfur atoms. While H-cluster architecture and catalytic states during the different steps of H2 turnover have been thoroughly investigated during the last 20 years, possible functional contributions from the polypeptide framework were only assumed according to the level of conservancy and X-ray structure analyses. Due to the recent development of simpler and more efficient expression systems the role of single amino acids can now be experimentally investigated. This article summarizes, compares and categorizes the results of recent investigations based on site directed and random mutagenesis according to their informative value about structure function relationships in [FeFe]-hydrogenases. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
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Affiliation(s)
- Martin Winkler
- Ruhr-Universität Bochum, Fakultät für Biologie und Biotechnologie, Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie, Bochum, Germany
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22
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Karnahl M, Tschierlei S, Erdem ÖF, Pullen S, Santoni MP, Reijerse EJ, Lubitz W, Ott S. Mixed-valence [Fe(I)Fe(II)] hydrogenase active site model complexes stabilized by a bidentate carborane bis-phosphine ligand. Dalton Trans 2013; 41:12468-77. [PMID: 22955116 DOI: 10.1039/c2dt31192e] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of [FeFe]-hydrogenase active site analogues, with the general formula [Fe(2)(dt)(CO)(4)(BC)] 1-3 (dt = dithiolate, pdt = propyl-1,3-dt (1), bdt = benzene-1,2-dt (2), edt = ethyl-1,2-dt (3); BC = 1,2-bisdiphenylphosphine-1,2-o-carborane), has been prepared and structurally characterized. While the electrochemical reductions of 1-3 are largely invariant to the different nature of their dt bridges, the oxidations differ by more than 120 mV in between the series. Remarkably, all three compounds are reversibly oxidized, with complex 1 that contains the most electron-donating pdt ligand at the mildest potential of -0.09 V vs. Fc/Fc(+). The one-electron oxidized state 1(ox) is stable for several minutes and was spectroscopically characterized by FTIR and EPR. EPR spectroscopy provided evidence that in the mixed-valence [Fe(I)Fe(II)] state most of the spin density is located on the iron with the BC-ligand. This is monitored through the strong (31)P hyperfine coupling of the phenyl groups of the BC ligand, while further delocalization into the o-carborane unit is negligible.
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Affiliation(s)
- Michael Karnahl
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden.
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23
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Soboh B, Stripp ST, Muhr E, Granich C, Braussemann M, Herzberg M, Heberle J, Gary Sawers R. [NiFe]-hydrogenase maturation: Isolation of a HypC-HypD complex carrying diatomic CO and CN−
ligands. FEBS Lett 2012; 586:3882-7. [DOI: 10.1016/j.febslet.2012.09.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
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24
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Kuchenreuther JM, Britt RD, Swartz JR. New insights into [FeFe] hydrogenase activation and maturase function. PLoS One 2012; 7:e45850. [PMID: 23049878 PMCID: PMC3457958 DOI: 10.1371/journal.pone.0045850] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/23/2012] [Indexed: 11/18/2022] Open
Abstract
[FeFe] hydrogenases catalyze H(2) production using the H-cluster, an iron-sulfur cofactor that contains carbon monoxide (CO), cyanide (CN(-)), and a dithiolate bridging ligand. The HydE, HydF, and HydG maturases assist in assembling the H-cluster and maturing hydrogenases into their catalytically active form. Characterization of these maturases and in vitro hydrogenase activation methods have helped elucidate steps in the H-cluster biosynthetic pathway such as the HydG-catalyzed generation of the CO and CN(-) ligands from free tyrosine. We have refined our cell-free approach for H-cluster synthesis and hydrogenase maturation by using separately expressed and purified HydE, HydF, and HydG. In this report, we illustrate how substrates and protein constituents influence hydrogenase activation, and for the first time, we show that each maturase can function catalytically during the maturation process. With precise control over the biomolecular components, we also provide evidence for H-cluster synthesis in the absence of either HydE or HydF, and we further show that hydrogenase activation can occur without exogenous tyrosine. Given these findings, we suggest a new reaction sequence for the [FeFe] hydrogenase maturation pathway. In our model, HydG independently synthesizes an iron-based compound with CO and CN(-) ligands that is a precursor to the H-cluster [2Fe](H) subunit, and which we have termed HydG-co. We further propose that HydF is a transferase that stabilizes HydG-co and also shuttles the complete [2Fe](H) subcluster to the hydrogenase, a translocation process that may be catalyzed by HydE. In summary, this report describes the first example of reconstructing the [FeFe] hydrogenase maturation pathway using purified maturases and subsequently utilizing this in vitro system to better understand the roles of HydE, HydF, and HydG.
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Affiliation(s)
- Jon M Kuchenreuther
- Department of Chemical Engineering, Stanford University, Stanford, California, USA
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25
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Schut GJ, Boyd ES, Peters JW, Adams MWW. The modular respiratory complexes involved in hydrogen and sulfur metabolism by heterotrophic hyperthermophilic archaea and their evolutionary implications. FEMS Microbiol Rev 2012; 37:182-203. [PMID: 22713092 DOI: 10.1111/j.1574-6976.2012.00346.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/30/2012] [Accepted: 06/08/2012] [Indexed: 12/01/2022] Open
Abstract
Hydrogen production is a vital metabolic process for many anaerobic organisms, and the enzyme responsible, hydrogenase, has been studied since the 1930s. A novel subfamily with unique properties was recently recognized, represented by the 14-subunit membrane-bound [NiFe] hydrogenase from the archaeon Pyrococcus furiosus. This so-called energy-converting hydrogenase links the thermodynamically favorable oxidation of ferredoxin with the formation of hydrogen and conserves energy in the form of an ion gradient. It is therefore a simple respiratory system within a single complex. This hydrogenase shows a modular composition represented by a Na(+)/H(+) antiporter domain (Mrp) and a [NiFe] hydrogenase domain (Mbh). An analysis of the large number of microbial genome sequences available shows that homologs of Mbh and Mrp tend to be clustered within the genomes of a limited number of archaeal and bacterial species. In several instances, additional genes are associated with the Mbh and Mrp gene clusters that encode proteins that catalyze the oxidation of formate, CO or NAD(P)H. The Mbh complex also shows extensive homology to a number of subunits within the NADH quinone oxidoreductase or complex I family. The respiratory-type membrane-bound hydrogenase complex appears to be closely related to the common ancestor of complex I and [NiFe] hydrogenases in general.
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Affiliation(s)
- Gerrit J Schut
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
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26
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Insights into [FeFe]-hydrogenase structure, mechanism, and maturation. Structure 2011; 19:1038-52. [PMID: 21827941 DOI: 10.1016/j.str.2011.06.008] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/01/2011] [Accepted: 06/09/2011] [Indexed: 01/06/2023]
Abstract
Hydrogenases are metalloenzymes that are key to energy metabolism in a variety of microbial communities. Divided into three classes based on their metal content, the [Fe]-, [FeFe]-, and [NiFe]-hydrogenases are evolutionarily unrelated but share similar nonprotein ligand assemblies at their active site metal centers that are not observed elsewhere in biology. These nonprotein ligands are critical in tuning enzyme reactivity, and their synthesis and incorporation into the active site clusters require a number of specific maturation enzymes. The wealth of structural information on different classes and different states of hydrogenase enzymes, biosynthetic intermediates, and maturation enzymes has contributed significantly to understanding the biochemistry of hydrogen metabolism. This review highlights the unique structural features of hydrogenases and emphasizes the recent biochemical and structural work that has created a clearer picture of the [FeFe]-hydrogenase maturation pathway.
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27
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Lambertz C, Leidel N, Havelius KGV, Noth J, Chernev P, Winkler M, Happe T, Haumann M. O2 reactions at the six-iron active site (H-cluster) in [FeFe]-hydrogenase. J Biol Chem 2011; 286:40614-23. [PMID: 21930709 DOI: 10.1074/jbc.m111.283648] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Irreversible inhibition by molecular oxygen (O(2)) complicates the use of [FeFe]-hydrogenases (HydA) for biotechnological hydrogen (H(2)) production. Modification by O(2) of the active site six-iron complex denoted as the H-cluster ([4Fe4S]-2Fe(H)) of HydA1 from the green alga Chlamydomonas reinhardtii was characterized by x-ray absorption spectroscopy at the iron K-edge. In a time-resolved approach, HydA1 protein samples were prepared after increasing O(2) exposure periods at 0 °C. A kinetic analysis of changes in their x-ray absorption near edge structure and extended X-ray absorption fine structure spectra revealed three phases of O(2) reactions. The first phase (τ(1) ≤ 4 s) is characterized by the formation of an increased number of Fe-O,C bonds, elongation of the Fe-Fe distance in the binuclear unit (2Fe(H)), and oxidation of one iron ion. The second phase (τ(2) ≈ 15 s) causes a ∼50% decrease of the number of ∼2.7-Å Fe-Fe distances in the [4Fe4S] subcluster and the oxidation of one more iron ion. The final phase (τ(3) ≤ 1000 s) leads to the disappearance of most Fe-Fe and Fe-S interactions and further iron oxidation. These results favor a reaction sequence, which involves 1) oxygenation at 2Fe(H(+)) leading to the formation of a reactive oxygen species-like superoxide (O(2)(-)), followed by 2) H-cluster inactivation and destabilization due to ROS attack on the [4Fe4S] cluster to convert it into an apparent [3Fe4S](+) unit, leading to 3) complete O(2)-induced degradation of the remainders of the H-cluster. This mechanism suggests that blocking of ROS diffusion paths and/or altering the redox potential of the [4Fe4S] cubane by genetic engineering may yield improved O(2) tolerance in [FeFe]-hydrogenase.
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Affiliation(s)
- Camilla Lambertz
- Lehrstuhl für Biochemie der Pflanzen, AG Photobiotechnologie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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Swanson KD, Duffus BR, Beard TE, Peters JW, Broderick JB. Cyanide and Carbon Monoxide Ligand Formation in Hydrogenase Biosynthesis. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201001056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kevin D. Swanson
- Department of Chemistry & Biochemistry, AstrobiologyBiogeocatalysis Research Center, Montana State University Bozeman, MT 59717, USA, Fax: +1‐406‐994‐7470
| | - Benjamin R. Duffus
- Department of Chemistry & Biochemistry, AstrobiologyBiogeocatalysis Research Center, Montana State University Bozeman, MT 59717, USA, Fax: +1‐406‐994‐7470
| | - Trevor E. Beard
- Department of Chemistry & Biochemistry, AstrobiologyBiogeocatalysis Research Center, Montana State University Bozeman, MT 59717, USA, Fax: +1‐406‐994‐7470
| | - John W. Peters
- Department of Chemistry & Biochemistry, AstrobiologyBiogeocatalysis Research Center, Montana State University Bozeman, MT 59717, USA, Fax: +1‐406‐994‐7470
| | - Joan B. Broderick
- Department of Chemistry & Biochemistry, AstrobiologyBiogeocatalysis Research Center, Montana State University Bozeman, MT 59717, USA, Fax: +1‐406‐994‐7470
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29
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Silakov A, Kamp C, Reijerse E, Happe T, Lubitz W. Spectroelectrochemical characterization of the active site of the [FeFe] hydrogenase HydA1 from Chlamydomonas reinhardtii. Biochemistry 2009; 48:7780-6. [PMID: 19634879 DOI: 10.1021/bi9009105] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydrogenases catalyze the reversible oxidation of molecular hydrogen. The active site of the [FeFe] hydrogenases (H-cluster) contains a catalytically active binuclear subcluster ([2Fe](H)) connected to a "cubane" [4Fe4S](H) subcluster. Here we present an IR spectroelectrochemical study of the [FeFe] hydrogenase HydA1 isolated from the green alga Chlamydomonas reinhardtii. The enzyme shows IR bands similar to those observed for bacterial [FeFe] hydrogenases. They are assigned to the stretching vibrations of the CN(-) and CO ligands on both irons of the [2Fe](H) subcluster. By following changes in frequencies of the IR bands during electrochemical titrations, two one-electron redox processes of the active enzyme could be distinguished. The reduction of the oxidized state (H(ox)) occurred at a midpoint potential of -400 mV vs NHE (H(ox)/H(red) transition) and relates to a change of the formal oxidation state of the binuclear subcluster. A subsequent reduction (H(red)/H(sred) transition) was determined to have a midpoint potential of -460 mV vs NHE. On the basis of the IR spectra, it is suggested that the oxidation state of the binuclear subcluster does not change in this transition. Tentatively, a reduction of the [4Fe4S](H) cluster has been proposed. In contrast to the bacterial [FeFe] hydrogenases, where the bridging CO ligand becomes terminal when going from H(ox) to H(red), in HydA1 the bridging CO is present in both the H(ox) and H(red) state. The removal of the bridging CO moiety has been observed in the H(red) to H(sred) transition. The significance of this result for the hydrogen conversion mechanism of this class of enzymes is discussed.
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Affiliation(s)
- Alexey Silakov
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
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30
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Tard C, Pickett CJ. Structural and functional analogues of the active sites of the [Fe]-, [NiFe]-, and [FeFe]-hydrogenases. Chem Rev 2009; 109:2245-74. [PMID: 19438209 DOI: 10.1021/cr800542q] [Citation(s) in RCA: 1014] [Impact Index Per Article: 67.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cédric Tard
- Laboratoire d'Electrochimie Moléculaire, Unité Mixte de Recherche Université-CNRS 7591, Université Paris Diderot, 75013 Paris, France
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31
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32
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Capon JF, Gloaguen F, Pétillon FY, Schollhammer P, Talarmin J. Electron and proton transfers at diiron dithiolate sites relevant to the catalysis of proton reduction by the [FeFe]-hydrogenases. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2008.10.020] [Citation(s) in RCA: 279] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Tanino S, Li Z, Ohki Y, Tatsumi K. A Dithiolate-Bridged (CN)2(CO)Fe−Ni Complex Reproducing the IR Bands of [NiFe] Hydrogenase. Inorg Chem 2009; 48:2358-60. [DOI: 10.1021/ic900017s] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Soichiro Tanino
- Department of Chemistry, Graduate School of Science, and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Zilong Li
- Department of Chemistry, Graduate School of Science, and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yasuhiro Ohki
- Department of Chemistry, Graduate School of Science, and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kazuyuki Tatsumi
- Department of Chemistry, Graduate School of Science, and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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34
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Peters JW. Carbon Monoxide and Cyanide Ligands in the Active Site of [FeFe]-Hydrogenases. METAL-CARBON BONDS IN ENZYMES AND COFACTORS 2009. [DOI: 10.1039/9781847559333-00179] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The [FeFe]-hydrogenases, although share common features when compared to other metal containing hydrogenases, clearly have independent evolutionary origins. Examples of [FeFe]-hydrogenases have been characterized in detail by biochemical and spectroscopic approaches and the high resolution structures of two examples have been determined. The active site H-cluster is a complex bridged metal assembly in which a [4Fe-4S] cubane is bridged to a 2Fe subcluster with unique non-protein ligands including carbon monoxide, cyanide, and a five carbon dithiolate. Carbon monoxide and cyanide ligands as a component of a native active metal center is a property unique to the metal containing hydrogenases and there has been considerable attention to the characterization of the H-cluster at the level of electronic structure and mechanism as well as to defining the biological means to synthesize such a unique metal cluster. The chapter describes the structural architecture of [FeFe]-hydrogenases and key spectroscopic observations that have afforded the field with a fundamental basis for understanding the relationship between structure and reactivity of the H-cluster. In addition, the results and ideas concerning the topic of H-cluster biosynthesis as an emerging and fascinating area of research, effectively reinforcing the potential linkage between iron-sulfur biochemistry to the role of iron-sulfur minerals in prebiotic chemistry and the origin of life.
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Affiliation(s)
- John W. Peters
- Montana State University, Department of Chemistry and Biochemistry and the Astrobiology Biogeocatalysis Research Center Bozeman, MT 59717 USA
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35
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Stripp ST, Happe T. How algae produce hydrogen—news from the photosynthetic hydrogenase. Dalton Trans 2009:9960-9. [DOI: 10.1039/b916246a] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mehanna M, Basseguy R, Delia ML, Girbal L, Demuez M, Bergel A. New hypotheses for hydrogenase implication in the corrosion of mild steel. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2008.02.101] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
The number of NADH dehydrogenases and their role in energy transduction in
Escherchia coli
have been under debate for a long time. Now it is evident that
E. coli
possesses two respiratory NADH dehydrogenases, or NADH:ubiquinone oxidoreductases, that have traditionally been called NDH-I and NDH-II. This review describes the properties of these two NADH dehydrogenases, focusing on the mechanism of the energy converting NADH dehydrogenase as derived from the high resolution structure of the soluble part of the enzyme. In
E. coli
, complex I operates in aerobic and anaerobic respiration, while NDH-II is repressed under anaerobic growth conditions. The insufficient recycling of NADH most likely resulted in excess NADH inhibiting tricarboxylic acid cycle enzymes and the glyoxylate shunt.
Salmonella enterica
serovar Typhimurium complex I mutants are unable to activate ATP-dependent proteolysis under starvation conditions. NDH-II is a single subunit enzyme with a molecular mass of 47 kDa facing the cytosol. Despite the absence of any predicted transmembrane segment it has to be purified in the presence of detergents, and the activity of the preparation is stimulated by an addition of lipids.
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38
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Fontecilla-Camps JC, Volbeda A, Cavazza C, Nicolet Y. Structure/function relationships of [NiFe]- and [FeFe]-hydrogenases. Chem Rev 2007; 107:4273-303. [PMID: 17850165 DOI: 10.1021/cr050195z] [Citation(s) in RCA: 998] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Juan C Fontecilla-Camps
- Laboratoire de Cristallographie et Cristallogenèse des Proteines, Institut de Biologie Structurale J. P. Ebel, CEA, CNRS, Universitè Joseph Fourier, 41 rue J. Horowitz, 38027 Grenoble Cedex 1, France.
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39
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Lubitz W, Reijerse E, van Gastel M. [NiFe] and [FeFe] Hydrogenases Studied by Advanced Magnetic Resonance Techniques. Chem Rev 2007; 107:4331-65. [PMID: 17845059 DOI: 10.1021/cr050186q] [Citation(s) in RCA: 423] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wolfgang Lubitz
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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40
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De Lacey AL, Fernandez VM, Rousset M, Cammack R. Activation and Inactivation of Hydrogenase Function and the Catalytic Cycle: Spectroelectrochemical Studies. Chem Rev 2007; 107:4304-30. [PMID: 17715982 DOI: 10.1021/cr0501947] [Citation(s) in RCA: 405] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Antonio L De Lacey
- Instituto de CatAlisis, CSIC, Marie Curie 2, Cantoblanco, 28049 Madrid, Spain
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41
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Forzi L, Sawers RG. Maturation of [NiFe]-hydrogenases in Escherichia coli. Biometals 2007; 20:565-78. [PMID: 17216401 DOI: 10.1007/s10534-006-9048-5] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Accepted: 11/28/2006] [Indexed: 10/23/2022]
Abstract
Hydrogenases catalyze the reversible oxidation of dihydrogen. Catalysis occurs at bimetallic active sites that contain either nickel and iron or only iron and the nature of these active sites forms the basis of categorizing the enzymes into three classes, the [NiFe]-hydrogenases, the [FeFe]-hydrogenases and the iron sulfur cluster-free [Fe]-hydrogenases. The [NiFe]-hydrogenases and the [FeFe]-hydrogenases are unrelated at the amino acid sequence level but the active sites share the unusual feature of having diatomic ligands associated with the Fe atoms in the these enzymes. Combined structural and spectroscopic studies of [NiFe]-hydrogenases identified these diatomic ligands as CN- and CO groups. Major advances in our understanding of the biosynthesis of these ligands have been achieved primarily through the study of the membrane-associated [NiFe]-hydrogenases of Escherichia coli. A complex biosynthetic machinery is involved in synthesis and attachment of these ligands to the iron atom, insertion of the Fe(CN)2CO group into the apo-hydrogenase, introduction of the nickel atom into the pre-formed active site and ensuring that the holoenzyme is correctly folded prior to delivery to the membrane. Although much remains to be uncovered regarding each of the individual biochemical steps on the pathway to synthesis of a fully functional enzyme, our understanding of the initial steps in CN- synthesis have revealed that it is generated from carbamoyl phosphate. What is becoming increasingly clear is that the metabolic origins of the carbonyl group may be different.
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Affiliation(s)
- Lucia Forzi
- Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
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42
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Abstract
Enzymes possessing the capacity to oxidize molecular hydrogen have developed convergently three class of enzymes leading to: [FeFe]-, [NiFe]-, and [FeS]-cluster-free hydrogenases. They differ in the composition and the structure of the active site metal centre and the sequence of the constituent structural polypeptides but they show one unifying feature, namely the existence of CN and/or CO ligands at the active site Fe. Recent developments in the analysis of the maturation of [FeFe]- and [NiFe]- hydrogenases have revealed a remarkably complex pattern of mostly novel biochemical reactions. Maturation of [FeFe]-hydrogenases requires a minimum of three auxiliary proteins, two of which belong to the class of Radical-SAM enzymes and other to the family of GTPases. They are sufficient to generate active enzyme when their genes are co-expressed with the structural genes in a heterologous host, otherwise deficient in [FeFe]-hydrogenase expression. Maturation of the large subunit of [NiFe]-hydrogenases depends on the activity of at least seven core proteins that catalyse the synthesis of the CN ligand, have a function in the coordination of the active site iron, the insertion of nickel and the proteolytic maturation of the large subunit. Whereas this core maturation machinery is sufficient to generate active hydrogenase in the cytoplasm, like that of hydrogenase 3 from Escherichia coli, additional proteins are involved in the export of the ready-assembled heterodimeric enzyme to the periplasm via the twin-arginine translocation system in the case of membrane-bound hydrogenases. A series of other gene products with intriguing putative functions indicate that the minimal pathway established for E. coli [NiFe]-hydrogenase maturation may possess even higher complexity in other organisms.
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Affiliation(s)
- August Böck
- Department Biology I, University of Munich, 80638 Munich, Germany
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43
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Long M, Liu J, Chen Z, Bleijlevens B, Roseboom W, Albracht SPJ. Characterization of a HoxEFUYH type of [NiFe] hydrogenase from Allochromatium vinosum and some EPR and IR properties of the hydrogenase module. J Biol Inorg Chem 2006; 12:62-78. [PMID: 16969669 DOI: 10.1007/s00775-006-0162-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Accepted: 08/11/2006] [Indexed: 10/24/2022]
Abstract
A soluble hydrogenase from Allochromatium vinosum was purified. It consisted of a large (M (r) = 52 kDa) and a small (M (r) = 23 kDa) subunit. The genes encoding for both subunits were identified. They belong to an open reading frame where they are preceded by three more genes. A DNA fragment containing all five genes was cloned and sequenced. The deduced amino acid sequences of the products characterized the complex as a member of the HoxEFUYH type of [NiFe] hydrogenases. Detailed sequence analyses revealed binding sites for eight Fe-S clusters, three [2Fe-2S] clusters and five [4Fe-4S] clusters, six of which are also present in homologous subunits of [FeFe] hydrogenases and NADH:ubiquione oxidoreductases (complex I). This makes the HoxEFUYH type of hydrogenases the one that is evolutionary closest to complex I. The relative positions of six of the potential Fe-S clusters are predicted on the basis of the X-ray structures of the Clostridium pasteurianum [FeFe] hydrogenase I and the hydrophilic domain of complex I from Thermus thermophilus. Although the HoxF subunit contains binding sites for flavin mononucleotide and NAD(H), cell-free extracts of A. vinosum did not catalyse a H(2)-dependent reduction of NAD(+). Only the hydrogenase module (HoxYH) could be purified. Its electron paramagnetic resonance (EPR) and IR spectral properties showed the presence of a Ni-Fe active site and a [4Fe-4S] cluster. Its activity was sensitive to carbon monoxide. No EPR signals from a light-sensitive Ni(a)-C* state could be observed. This study presents the first IR spectroscopic data on the HoxYH module of a HoxEFUYH type of [NiFe] hydrogenase.
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Affiliation(s)
- Minnan Long
- School of Life Sciences, Bio-energy Center, Xiamen University, Xiamen, 361005, People's Republic of China.
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44
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Roseboom W, De Lacey AL, Fernandez VM, Hatchikian EC, Albracht SPJ. The active site of the [FeFe]-hydrogenase from Desulfovibrio desulfuricans. II. Redox properties, light sensitivity and CO-ligand exchange as observed by infrared spectroscopy. J Biol Inorg Chem 2005; 11:102-18. [PMID: 16323019 DOI: 10.1007/s00775-005-0040-2] [Citation(s) in RCA: 180] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Accepted: 09/26/2005] [Indexed: 10/25/2022]
Abstract
In [FeFe]-hydrogenases, the H cluster (hydrogen-activating cluster) contains a di-iron centre ([2Fe]H subcluster, a (L)(CO)(CN)Fe(mu-RS2)(mu-CO)Fe(CysS)(CO)(CN) group) covalently attached to a cubane iron-sulphur cluster ([4Fe-4S]H subcluster). The Cys-thiol functions as the link between one iron (called Fe1) of the [2Fe]H subcluster and one iron of the cubane subcluster. The other iron in the [2Fe]H subcluster is called Fe2. The light sensitivity of the Desulfovibrio desulfuricans enzyme in a variety of states has been studied with infrared (IR) spectroscopy. The aerobic inactive enzyme (H(inact) state) and the CO-inhibited active form (H(ox)-CO state) were stable in light. Illumination of the H(ox) state led to a kind of cannibalization; in some enzyme molecules the H cluster was destroyed and the released CO was captured by the H clusters in other molecules to form the light-stable H(ox)-CO state. Illumination of active enzyme under 13CO resulted in the complete exchange of the two intrinsic COs bound to Fe2. At cryogenic temperatures, light induced the photodissociation of the extrinsic CO and the bridging CO of the enzyme in the H(ox)-CO state. Electrochemical redox titrations showed that the enzyme in the H(inact) state converts to the transition state (H(trans)) in a reversible one-electron redox step (E (m, pH 7) = -75 mV). IR spectra demonstrate that the added redox equivalent not only affects the [4Fe-4S]H subcluster, but also the di-iron centre. Enzyme in the H(trans) state reacts with extrinsic CO, which binds to Fe2. The H(trans) state converts irreversibly into the H(ox) state in a redox-dependent reaction most likely involving two electrons (E (m, pH 7) = -261 mV). These electrons do not end up on any of the six Fe atoms of the H cluster; the possible destiny of the two redox equivalents is discussed. An additional reversible one-electron redox reaction leads to the H(red) state (E (m, pH 7) = -354 mV), where both Fe atoms of the [2Fe]H subcluster have the same formal oxidation state. The possible oxidation states of Fe1 and Fe2 in the various enzyme states are discussed. Low redox potentials (below -500 mV) lead to destruction of the [2Fe]H subcluster.
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Affiliation(s)
- Winfried Roseboom
- Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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45
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Albracht SPJ, Roseboom W, Hatchikian EC. The active site of the [FeFe]-hydrogenase from Desulfovibrio desulfuricans. I. Light sensitivity and magnetic hyperfine interactions as observed by electron paramagnetic resonance. J Biol Inorg Chem 2005; 11:88-101. [PMID: 16323020 DOI: 10.1007/s00775-005-0039-8] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Accepted: 09/26/2005] [Indexed: 10/25/2022]
Abstract
The hydrogen-activating cluster (H cluster) in [FeFe]-hydrogenases consists of two moieties. The [2Fe]H subcluster is a (L)(CO)(CN)Fe(mu-RS2)(mu-CO)Fe(CysS)(CO)(CN) centre. The Cys-bound Fe is called Fe1, the other iron Fe2. The Cys-thiol forms a bridge to a [4Fe-4S] cluster, the [4Fe-4S]H subcluster. We report that electron paramagnetic resonance (EPR) spectra of the 57Fe-enriched enzyme from Desulfovibrio desulfuricans in the H(ox)-CO state are consistent with a magnetic hyperfine interaction of the unpaired spin with all six Fe atoms of the H cluster. In contrast to the inactive aerobic enzyme, the active enzyme is easily destroyed by light. The [2Fe]H subcluster in some enzyme molecules loses CO by photolysis, whereupon other molecules firmly bind the released CO to form the H(ox)-CO state giving rise to the so-called axial 2.06 EPR signal. Though not destroyed by light, the H(ox)-CO state is affected by it. As demonstrated in the accompanying paper [49] two of the intrinsic COs, both bound to Fe2, can be exchanged by extrinsic 13CO during illumination at 2 degrees C. We found that only one of the three 13COs, the one at the extrinsic position, gives an EPR-detectable isotropic superhyperfine interaction of 0.6 mT. At 30 K both the inhibiting extrinsic CO bound to Fe2 and one more CO can be photolysed. EPR spectra of the photolysed products are consistent with a 3d7 system of Fe with the formal oxidation state +1. The damaged enzyme shows a light-sensitive g = 5 signal which is ascribed to an S = 3/2 form of the [2Fe](H) subcluster. The light sensitivity of the enzyme explains the occurrence of the g = 5 signal and the axial 2.06 signal in published EPR spectra of nearly all preparations studied thus far.
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Affiliation(s)
- Simon P J Albracht
- Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV, Amsterdam, The Netherlands,
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46
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Brazzolotto X, Rubach JK, Gaillard J, Gambarelli S, Atta M, Fontecave M. The [Fe-Fe]-hydrogenase maturation protein HydF from Thermotoga maritima is a GTPase with an iron-sulfur cluster. J Biol Chem 2005; 281:769-74. [PMID: 16278209 DOI: 10.1074/jbc.m510310200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The active site of [Fe-Fe]-hydrogenases is composed of a di-iron complex, where the two metal atoms are bridged together by a putative di(thiomethyl)amine molecule and are also ligated by di-nuclear ligands, namely carbon monoxide and cyanide. Biosynthesis of this metal site is thought to require specific protein machinery coded by the hydE, hydF, and hydG genes. The HydF protein has been cloned from the thermophilic organism Thermotoga maritima, purified, and characterized. The enzyme possesses specific amino acid signatures for GTP binding and is able to hydrolyze GTP. The anaerobically reconstituted TmHydF protein binds a [4Fe-4S] cluster with peculiar EPR characteristics: an S = 1/2 signal presenting a high field shifted g-value together with a S = 3/2 signal, similar to those observed for [4Fe-4S] clusters ligated by only three cysteines. HYSCORE spectroscopy experiments were carried out to determine the nature of the fourth ligand of the cluster, and its exchangeability was demonstrated with the formation of a [4Fe-4S]-imidazole complex.
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Affiliation(s)
- Xavier Brazzolotto
- Laboratoire de Chimie et Biochimie des Centres Rédox Biologiques, UMR Université Joseph Fourier/CNRS/Commissariat à l'Energie Atomique-No. 5047, Grenoble, France
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47
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Burgdorf T, van der Linden E, Bernhard M, Yin QY, Back JW, Hartog AF, Muijsers AO, de Koster CG, Albracht SPJ, Friedrich B. The soluble NAD+-Reducing [NiFe]-hydrogenase from Ralstonia eutropha H16 consists of six subunits and can be specifically activated by NADPH. J Bacteriol 2005; 187:3122-32. [PMID: 15838039 PMCID: PMC1082810 DOI: 10.1128/jb.187.9.3122-3132.2005] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The soluble [NiFe]-hydrogenase (SH) of the facultative lithoautotrophic proteobacterium Ralstonia eutropha H16 has up to now been described as a heterotetrameric enzyme. The purified protein consists of two functionally distinct heterodimeric moieties. The HoxHY dimer represents the hydrogenase module, and the HoxFU dimer constitutes an NADH-dehydrogenase. In the bimodular form, the SH mediates reduction of NAD(+) at the expense of H(2). We have purified a new high-molecular-weight form of the SH which contains an additional subunit. This extra subunit was identified as the product of hoxI, a member of the SH gene cluster (hoxFUYHWI). Edman degradation, in combination with protein sequencing of the SH high-molecular-weight complex, established a subunit stoichiometry of HoxFUYHI(2). Cross-linking experiments indicated that the two HoxI subunits are the closest neighbors. The stability of the hexameric SH depended on the pH and the ionic strength of the buffer. The tetrameric form of the SH can be instantaneously activated with small amounts of NADH but not with NADPH. The hexameric form, however, was also activated by adding small amounts of NADPH. This suggests that HoxI provides a binding domain for NADPH. A specific reaction site for NADPH adds to the list of similarities between the SH and mitochondrial NADH:ubiquinone oxidoreductase (Complex I).
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Affiliation(s)
- Tanja Burgdorf
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, D-10115 Berlin, Germany
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48
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Armstrong FA, Albracht SPJ. [NiFe]-hydrogenases: spectroscopic and electrochemical definition of reactions and intermediates. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2005; 363:937-54; discussion 1035-40. [PMID: 15991402 DOI: 10.1098/rsta.2004.1528] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Production and usage of di-hydrogen, H2, in micro-organisms is catalysed by highly active, 'ancient' metalloenzymes known as hydrogenases. Based on the number and identity of metal atoms in their active sites, hydrogenases fall into three main classes, [NiFe]-, [FeFe]- and [Fe]-. All contain the unusual ligand CO (and in most cases CN- as well) making them intriguing examples of 'organometallic' cofactors. These ligands render the active sites superbly 'visible' using infrared spectroscopy, which complements the use of electron paramagnetic resonance spectroscopy in studying mechanisms and identifying intermediates. Hydrogenases are becoming a focus of attention for research into future energy technologies, not only H2 production but also H2 oxidation in fuel cells. Hydrogenases immobilized on electrodes exhibit high electrocatalytic activity, providing not only an important new technique for their investigation, but also a basis for novel fuel cells either using the enzyme itself, or inspired synthetic catalysts. Favourable comparisons have been made with platinum electrocatalysts, an advantage of enzymes being their specificity for H2 and tolerance of CO. A challenge for exploiting hydrogenases is their sensitivity to O2, but some organisms are known to produce enzymes that overcome this problem by subtle alterations of the active site and gas access channels.
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Affiliation(s)
- Fraser A Armstrong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, UK.
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49
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50
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Sawers RG, Blokesch M, Böck A. Anaerobic Formate and Hydrogen Metabolism. EcoSal Plus 2004; 1. [PMID: 26443350 DOI: 10.1128/ecosalplus.3.5.4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Indexed: 06/05/2023]
Abstract
During fermentative growth, Escherichia coli degrades carbohydrates via the glycolytic route into two pyruvate molecules. Pyruvate can be reduced to lactate or nonoxidatively cleaved by pyruvate formate lyase into acetyl-coenzyme A (acetyl-CoA) and formate. Acetyl-CoA can be utilized for energy conservation in the phosphotransacetylase (PTA) and acetate kinase (ACK) reaction sequence or can serve as an acceptor for reducing equivalents gathered during pyruvate formation, through the action of alcohol dehydrogenase (AdhE). Formic acid is strongly acidic and has a redox potential of -420 mV under standard conditions and therefore can be classified as a high-energy compound. Its disproportionation into CO2 and molecular hydrogen (Em,7 -420 mV) via the formate hydrogenlyase (FHL) system is therefore of high selective value. The FHL reaction involves the participation of at least seven proteins, most of which are metalloenzymes, with requirements for iron, molybdenum, nickel, or selenium. Complex auxiliary systems incorporate these metals. Reutilization of the hydrogen evolved required the evolution of H2 oxidation systems, which couple the oxidation process to an appropriate energy-conserving terminal reductase. E. coli has two hydrogen-oxidizing enzyme systems. Finally, fermentation is the "last resort" of energy metabolism, since it gives the minimal energy yield when compared with respiratory processes. Consequently, fermentation is used only when external electron acceptors are absent. This has necessitated the establishment of regulatory cascades, which ensure that the metabolic capability is appropriately adjusted to the physiological condition. Here we review the genetics, biochemistry, and regulation of hydrogen metabolism and its hydrogenase maturation system.
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