1
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Grunwald L, Abbott DF, Mougel V. Gauging Iron-Sulfur Cubane Reactivity from Covalency: Trends with Oxidation State. JACS AU 2024; 4:1315-1322. [PMID: 38665672 PMCID: PMC11040707 DOI: 10.1021/jacsau.4c00213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 04/28/2024]
Abstract
We investigated room-temperature metal and ligand K-edge X-ray absorption (XAS) spectra of a complete redox series of cubane-type iron-sulfur clusters. The Fe K-edge position provides a qualitative but convenient alternative to the traditional spectroscopic descriptors used to identify oxidation states in these systems, which we demonstrate by providing a calibration curve based on two analytic methods. Furthermore, high energy resolution fluorescence detected XAS (HERFD-XAS) at the S K-edge was used to measure Fe-S bond covalencies and record their variation with the average valence of the Fe atoms. While the Fe-S(thiolate) covalency evolves linearly, gaining 11 ± 0.4% per bond and hole, the Fe-S(μ3) covalency evolves asystematically, reflecting changes in the magnetic exchange mechanism. A strong discontinuity manifested for superoxidation to the all-ferric state, distinguishing its electronic structure and its potential (bio)chemical role from those of its redox congeners. We highlight the functional implications of these trends for the reactivity of iron-sulfur cubanes.
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Affiliation(s)
- Liam Grunwald
- Department
of Chemistry and Applied Biosciences (D-CHAB), Swiss Federal Institute of Technology Zürich (ETHZ), Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Daniel F. Abbott
- Department
of Chemistry and Applied Biosciences (D-CHAB), Swiss Federal Institute of Technology Zürich (ETHZ), Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Victor Mougel
- Department
of Chemistry and Applied Biosciences (D-CHAB), Swiss Federal Institute of Technology Zürich (ETHZ), Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
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2
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Cabotaje P, Walter K, Zamader A, Huang P, Ho F, Land H, Senger M, Berggren G. Probing Substrate Transport Effects on Enzymatic Hydrogen Catalysis: An Alternative Proton Transfer Pathway in Putatively Sensory [FeFe] Hydrogenase. ACS Catal 2023; 13:10435-10446. [PMID: 37560193 PMCID: PMC10407848 DOI: 10.1021/acscatal.3c02314] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/04/2023] [Indexed: 08/11/2023]
Abstract
[FeFe] hydrogenases, metalloenzymes catalyzing proton/dihydrogen interconversion, have attracted intense attention due to their remarkable catalytic properties and (bio-)technological potential for a future hydrogen economy. In order to unravel the factors enabling their efficient catalysis, both their unique organometallic cofactors and protein structural features, i.e., "outer-coordination sphere" effects have been intensively studied. These structurally diverse enzymes are divided into distinct phylogenetic groups, denoted as Group A-D. Prototypical Group A hydrogenases display high turnover rates (104-105 s-1). Conversely, the sole characterized Group D representative, Thermoanaerobacter mathranii HydS (TamHydS), shows relatively low catalytic activity (specific activity 10-1 μmol H2 mg-1 min-1) and has been proposed to serve a H2-sensory function. The various groups of [FeFe] hydrogenase share the same catalytic cofactor, the H-cluster, and the structural factors causing the diverging reactivities of Group A and D remain to be elucidated. In the case of the highly active Group A enzymes, a well-defined proton transfer pathway (PTP) has been identified, which shuttles H+ between the enzyme surface and the active site. In Group D hydrogenases, this conserved pathway is absent. Here, we report on the identification of highly conserved amino acid residues in Group D hydrogenases that constitute a possible alternative PTP. We varied two proposed key amino acid residues of this pathway (E252 and E289, TamHydS numbering) via site-directed mutagenesis and analyzed the resulting variants via biochemical and spectroscopic methods. All variants displayed significantly decreased H2-evolution and -oxidation activities. Additionally, the variants showed two redox states that were not characterized previously. These findings provide initial evidence that these amino acid residues are central to the putative PTP of Group D [FeFe] hydrogenase. Since the identified residues are highly conserved in Group D exclusively, our results support the notion that the PTP is not universal for different phylogenetic groups in [FeFe] hydrogenases.
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Affiliation(s)
| | | | - Afridi Zamader
- Molecular Biomimetics, Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Ping Huang
- Molecular Biomimetics, Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Felix Ho
- Molecular Biomimetics, Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Henrik Land
- Molecular Biomimetics, Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Moritz Senger
- Molecular Biomimetics, Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Gustav Berggren
- Molecular Biomimetics, Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
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3
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Runda ME, de Kok NAW, Schmidt S. Rieske Oxygenases and Other Ferredoxin-Dependent Enzymes: Electron Transfer Principles and Catalytic Capabilities. Chembiochem 2023; 24:e202300078. [PMID: 36964978 DOI: 10.1002/cbic.202300078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 03/27/2023]
Abstract
Enzymes that depend on sophisticated electron transfer via ferredoxins (Fds) exhibit outstanding catalytic capabilities, but despite decades of research, many of them are still not well understood or exploited for synthetic applications. This review aims to provide a general overview of the most important Fd-dependent enzymes and the electron transfer processes involved. While several examples are discussed, we focus in particular on the family of Rieske non-heme iron-dependent oxygenases (ROs). In addition to illustrating their electron transfer principles and catalytic potential, the current state of knowledge on structure-function relationships and the mode of interaction between the redox partner proteins is reviewed. Moreover, we highlight several key catalyzed transformations, but also take a deeper dive into their engineerability for biocatalytic applications. The overall findings from these case studies highlight the catalytic capabilities of these biocatalysts and could stimulate future interest in developing additional Fd-dependent enzyme classes for synthetic applications.
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Affiliation(s)
- Michael E Runda
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Niels A W de Kok
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Sandy Schmidt
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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4
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Corrigan PS, Majer SH, Silakov A. Evidence of Atypical Structural Flexibility of the Active Site Surrounding of an [FeFe] Hydrogenase from Clostridium beijerinkii. J Am Chem Soc 2023; 145:11033-11044. [PMID: 37163727 DOI: 10.1021/jacs.2c13458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
[FeFe] hydrogenase from Clostridium beijerinkii (CbHydA1) is an unusual hydrogenase in that it can withstand prolonged exposure to O2 by reversibly converting into an O2-protected, inactive state (Hinact). It has been indicated in the past that an atypical conformation of the "SC367CP" loop near the [2Fe]H portion of the six-iron active site (H-cluster) allows the Cys367 residue to adopt an "off-H+-pathway" orientation, promoting a facile transition of the cofactor to Hinact. Here, we investigated the electronic structure of the H-cluster in the oxidized state (Hox) that directly converts to Hinact under oxidizing conditions and the related CO-inhibited state (Hox-CO). We demonstrate that both states exhibit two distinct forms in electron paramagnetic resonance (EPR) spectroscopy. The ratio between the two forms is pH-dependent but also sensitive to the buffer choice. Our IR and EPR analyses illustrate that the spectral heterogeneity is due to a perturbation of the coordination environment of the H-cluster's [4Fe4S]H subcluster without affecting the [2Fe]H subcluster. Overall, we conclude that the observation of two spectral components per state is evidence of heterogeneity of the environment of the H-cluster likely associated with conformational mobility of the SCCP loop. Such flexibility may allow Cys367 to switch rapidly between off- and on-H+-pathway rotamers. Consequently, we believe such structural mobility may be the key to maintaining high enzymatic activity while allowing a facile transition to the O2-protected state.
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Affiliation(s)
- Patrick S Corrigan
- Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Sean H Majer
- Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Alexey Silakov
- Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
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5
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Martini MA, Bikbaev K, Pang Y, Lorent C, Wiemann C, Breuer N, Zebger I, DeBeer S, Span I, Bjornsson R, Birrell JA, Rodríguez-Maciá P. Binding of exogenous cyanide reveals new active-site states in [FeFe] hydrogenases. Chem Sci 2023; 14:2826-2838. [PMID: 36937599 PMCID: PMC10016341 DOI: 10.1039/d2sc06098a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/07/2023] [Indexed: 02/10/2023] Open
Abstract
[FeFe] hydrogenases are highly efficient metalloenyzmes for hydrogen conversion. Their active site cofactor (the H-cluster) is composed of a canonical [4Fe-4S] cluster ([4Fe-4S]H) linked to a unique organometallic di-iron subcluster ([2Fe]H). In [2Fe]H the two Fe ions are coordinated by a bridging 2-azapropane-1,3-dithiolate (ADT) ligand, three CO and two CN- ligands, leaving an open coordination site on one Fe where substrates (H2 and H+) as well as inhibitors (e.g. O2, CO, H2S) may bind. Here, we investigate two new active site states that accumulate in [FeFe] hydrogenase variants where the cysteine (Cys) in the proton transfer pathway is mutated to alanine (Ala). Our experimental data, including atomic resolution crystal structures and supported by calculations, suggest that in these two states a third CN- ligand is bound to the apical position of [2Fe]H. These states can be generated both by "cannibalization" of CN- from damaged [2Fe]H subclusters as well as by addition of exogenous CN-. This is the first detailed spectroscopic and computational characterisation of the interaction of exogenous CN- with [FeFe] hydrogenases. Similar CN--bound states can also be generated in wild-type hydrogenases, but do not form as readily as with the Cys to Ala variants. These results highlight how the interaction between the first amino acid in the proton transfer pathway and the active site tunes ligand binding to the open coordination site and affects the electronic structure of the H-cluster.
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Affiliation(s)
- Maria Alessandra Martini
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion Stiftstraße 34-36 45470 Mülheim an der Ruhr Germany
| | - Konstantin Bikbaev
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nürnberg Bioinorganic Chemistry Erlangen Germany
| | - Yunjie Pang
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion Stiftstraße 34-36 45470 Mülheim an der Ruhr Germany
- College of Chemistry, Beijing Normal University 100875 Beijing China
| | - Christian Lorent
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Charlotte Wiemann
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
- Ruanda-Zentrum und Büro für Afrika-Kooperationen, Universität Koblenz-Landau, Universitätsstraße 1 56070 Koblenz Germany
| | - Nina Breuer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion Stiftstraße 34-36 45470 Mülheim an der Ruhr Germany
| | - Ingo Zebger
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Serena DeBeer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion Stiftstraße 34-36 45470 Mülheim an der Ruhr Germany
| | - Ingrid Span
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nürnberg Bioinorganic Chemistry Erlangen Germany
| | - Ragnar Bjornsson
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion Stiftstraße 34-36 45470 Mülheim an der Ruhr Germany
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux 17 Rue des Martyrs F-38054 Grenoble Cedex France
| | - James A Birrell
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion Stiftstraße 34-36 45470 Mülheim an der Ruhr Germany
- School of Life Sciences, University of Essex Colchester CO4 3SQ UK
| | - Patricia Rodríguez-Maciá
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford South Parks Road Oxford OX1 3QR UK
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6
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Katsyv A, Kumar A, Saura P, Pöverlein MC, Freibert SA, T Stripp S, Jain S, Gamiz-Hernandez AP, Kaila VRI, Müller V, Schuller JM. Molecular Basis of the Electron Bifurcation Mechanism in the [FeFe]-Hydrogenase Complex HydABC. J Am Chem Soc 2023; 145:5696-5709. [PMID: 36811855 PMCID: PMC10021017 DOI: 10.1021/jacs.2c11683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Electron bifurcation is a fundamental energy coupling mechanism widespread in microorganisms that thrive under anoxic conditions. These organisms employ hydrogen to reduce CO2, but the molecular mechanisms have remained enigmatic. The key enzyme responsible for powering these thermodynamically challenging reactions is the electron-bifurcating [FeFe]-hydrogenase HydABC that reduces low-potential ferredoxins (Fd) by oxidizing hydrogen gas (H2). By combining single-particle cryo-electron microscopy (cryoEM) under catalytic turnover conditions with site-directed mutagenesis experiments, functional studies, infrared spectroscopy, and molecular simulations, we show that HydABC from the acetogenic bacteria Acetobacterium woodii and Thermoanaerobacter kivui employ a single flavin mononucleotide (FMN) cofactor to establish electron transfer pathways to the NAD(P)+ and Fd reduction sites by a mechanism that is fundamentally different from classical flavin-based electron bifurcation enzymes. By modulation of the NAD(P)+ binding affinity via reduction of a nearby iron-sulfur cluster, HydABC switches between the exergonic NAD(P)+ reduction and endergonic Fd reduction modes. Our combined findings suggest that the conformational dynamics establish a redox-driven kinetic gate that prevents the backflow of the electrons from the Fd reduction branch toward the FMN site, providing a basis for understanding general mechanistic principles of electron-bifurcating hydrogenases.
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Affiliation(s)
- Alexander Katsyv
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Anuj Kumar
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany.,SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg 35032, Germany
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Maximilian C Pöverlein
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Sven A Freibert
- Institut für Zytobiologie im Zentrum SYNMIKRO, Philipps-University of Marburg, Marburg 35032, Germany.,Core Facility "Protein Biochemistry and Spectroscopy", Marburg 35032, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin 14195, Germany
| | - Surbhi Jain
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Jan M Schuller
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg 35032, Germany
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7
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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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8
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Grinter R, Kropp A, Venugopal H, Senger M, Badley J, Cabotaje PR, Jia R, Duan Z, Huang P, Stripp ST, Barlow CK, Belousoff M, Shafaat HS, Cook GM, Schittenhelm RB, Vincent KA, Khalid S, Berggren G, Greening C. Structural basis for bacterial energy extraction from atmospheric hydrogen. Nature 2023; 615:541-547. [PMID: 36890228 PMCID: PMC10017518 DOI: 10.1038/s41586-023-05781-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 02/02/2023] [Indexed: 03/10/2023]
Abstract
Diverse aerobic bacteria use atmospheric H2 as an energy source for growth and survival1. This globally significant process regulates the composition of the atmosphere, enhances soil biodiversity and drives primary production in extreme environments2,3. Atmospheric H2 oxidation is attributed to uncharacterized members of the [NiFe] hydrogenase superfamily4,5. However, it remains unresolved how these enzymes overcome the extraordinary catalytic challenge of oxidizing picomolar levels of H2 amid ambient levels of the catalytic poison O2 and how the derived electrons are transferred to the respiratory chain1. Here we determined the cryo-electron microscopy structure of the Mycobacterium smegmatis hydrogenase Huc and investigated its mechanism. Huc is a highly efficient oxygen-insensitive enzyme that couples oxidation of atmospheric H2 to the hydrogenation of the respiratory electron carrier menaquinone. Huc uses narrow hydrophobic gas channels to selectively bind atmospheric H2 at the expense of O2, and 3 [3Fe-4S] clusters modulate the properties of the enzyme so that atmospheric H2 oxidation is energetically feasible. The Huc catalytic subunits form an octameric 833 kDa complex around a membrane-associated stalk, which transports and reduces menaquinone 94 Å from the membrane. These findings provide a mechanistic basis for the biogeochemically and ecologically important process of atmospheric H2 oxidation, uncover a mode of energy coupling dependent on long-range quinone transport, and pave the way for the development of catalysts that oxidize H2 in ambient air.
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Affiliation(s)
- Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
| | - Ashleigh Kropp
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Hari Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Moritz Senger
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Jack Badley
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Princess R Cabotaje
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Ruyu Jia
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Zehui Duan
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
| | - Ping Huang
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Christopher K Barlow
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Matthew Belousoff
- Centre for Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Hannah S Shafaat
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Ralf B Schittenhelm
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
- Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia.
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia.
- ARC Research Hub for Carbon Utilisation and Recycling, Monash University, Clayton, Victoria, Australia.
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9
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Torres A, Collado A, Gómez-Gallego M, de Arellano CR, Sierra MA. Heteropolymetallic [FeFe]-Hydrogenase Mimics: Synthesis and Electrochemical Properties. Inorg Chem 2023; 62:3409-3419. [PMID: 36780261 PMCID: PMC9976291 DOI: 10.1021/acs.inorgchem.2c03355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Indexed: 02/14/2023]
Abstract
The synthesis and electrochemical properties of tetranuclear [Fe2S2]-hydrogenase mimic species containing Pt(II), Ni(II), and Ru(II) complexes have been studied. To this end, a new tetranuclear [Fe2S2] complex containing a 5,5'-diisocyanide-2,2'-bipyridine bridging ligand has been designed and coordinated to the metal complexes through the bipyridine moiety. Thus, the tetranuclear [Fe2S2] complex (6) coordinates to Pt(II), Ni(II) and Ru(II) yielding the corresponding metal complexes. The new metal center in the bipyridine linker modulates the electronic communication between the redox-active [Fe2S2] units. Thus, electrochemical studies and DFT calculations have shown that the presence of metal complexes in the structure strongly affect the electronic communication between the [Fe2S2] centers. In the case of diphosphine platinum compounds 10, the structure of the phosphine ligand plays a crucial role to facilitate or to hinder the electronic communication between [Fe2S2] moieties. Compound 10a, bearing a dppe ligand, shows weak electronic communication (ΔE = 170 mV), whereas the interaction is much weaker in the Pt-dppp derivative 10b (ΔE = 80 mV) and virtually negligible in the Pt-dppf complex 10c. The electronic communication is facilitated by incorporation of a Ru-bis(bipyridine) complex, as observed in the BF4 salt 12 (ΔE = 210 mV) although the reduction of the [FeFe] centers occurs at more negative potentials. Overall, the experimental-computational procedure used in this work allows us to study the electronic interaction between the redox-active centers, which, in turn, can be modulated by a transition metal.
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Affiliation(s)
- Alejandro Torres
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
- Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - Alba Collado
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
- Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - Mar Gómez-Gallego
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
- Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - Carmen Ramírez de Arellano
- Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
- Departamento
de Química Orgánica, Universidad
de Valencia, 46100 Valencia, Spain
| | - Miguel A. Sierra
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
- Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
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10
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Lorenzi M, Gamache MT, Redman HJ, Land H, Senger M, Berggren G. Light-Driven [FeFe] Hydrogenase Based H 2 Production in E. coli: A Model Reaction for Exploring E. coli Based Semiartificial Photosynthetic Systems. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2022; 10:10760-10767. [PMID: 36035441 PMCID: PMC9400101 DOI: 10.1021/acssuschemeng.2c03657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/08/2022] [Indexed: 06/01/2023]
Abstract
Biohybrid technologies like semiartificial photosynthesis are attracting increased attention, as they enable the combination of highly efficient synthetic light-harvesters with the self-healing and outstanding performance of biocatalysis. However, such systems are intrinsically complex, with multiple interacting components. Herein, we explore a whole-cell photocatalytic system for hydrogen (H2) gas production as a model system for semiartificial photosynthesis. The employed whole-cell photocatalytic system is based on Escherichia coli cells heterologously expressing a highly efficient, but oxygen-sensitive, [FeFe] hydrogenase. The system is driven by the organic photosensitizer eosin Y under broad-spectrum white light illumination. The direct involvement of the [FeFe] hydrogenase in the catalytic reaction is verified spectroscopically. We also observe that E. coli provides protection against O2 damage, underscoring the suitability of this host organism for oxygen-sensitive enzymes in the development of (photo) catalytic biohybrid systems. Moreover, the study shows how factorial experimental design combined with analysis of variance (ANOVA) can be employed to identify relevant variables, as well as their interconnectivity, on both overall catalytic performance and O2 tolerance.
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Affiliation(s)
- Marco Lorenzi
- Department
of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, Lägerhyddsvägen 1, 75120 Uppsala, Sweden
| | - Mira T. Gamache
- Department
of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, Lägerhyddsvägen 1, 75120 Uppsala, Sweden
| | - Holly J. Redman
- Department
of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, Lägerhyddsvägen 1, 75120 Uppsala, Sweden
| | - Henrik Land
- Department
of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, Lägerhyddsvägen 1, 75120 Uppsala, Sweden
| | - Moritz Senger
- Department
of Chemistry - Ångström, Physical Chemistry, Uppsala University, Lägerhyddsvägen 1, 75120 Uppsala, Sweden
| | - Gustav Berggren
- Department
of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, Lägerhyddsvägen 1, 75120 Uppsala, Sweden
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11
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Pavliuk MV, Lorenzi M, Morado DR, Gedda L, Wrede S, Mejias SH, Liu A, Senger M, Glover S, Edwards K, Berggren G, Tian H. Polymer Dots as Photoactive Membrane Vesicles for [FeFe]-Hydrogenase Self-Assembly and Solar-Driven Hydrogen Evolution. J Am Chem Soc 2022; 144:13600-13611. [PMID: 35863067 PMCID: PMC9354254 DOI: 10.1021/jacs.2c03882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A semiartificial photosynthesis approach that utilizes enzymes for solar fuel production relies on efficient photosensitizers that should match the enzyme activity and enable long-term stability. Polymer dots (Pdots) are biocompatible photosensitizers that are stable at pH 7 and have a readily modifiable surface morphology. Therefore, Pdots can be considered potential photosensitizers to drive such enzyme-based systems for solar fuel formation. This work introduces and unveils in detail the interaction within the biohybrid assembly composed of binary Pdots and the HydA1 [FeFe]-hydrogenase from Chlamydomonas reinhardtii. The direct attachment of hydrogenase on the surface of toroid-shaped Pdots was confirmed by agarose gel electrophoresis, cryogenic transmission electron microscopy (Cryo-TEM), and cryogenic electron tomography (Cryo-ET). Ultrafast transient spectroscopic techniques were used to characterize photoinduced excitation and dissociation into charges within Pdots. The study reveals that implementation of a donor-acceptor architecture for heterojunction Pdots leads to efficient subpicosecond charge separation and thus enhances hydrogen evolution (88 460 μmolH2·gH2ase-1·h-1). Adsorption of [FeFe]-hydrogenase onto Pdots resulted in a stable biohybrid assembly, where hydrogen production persisted for days, reaching a TON of 37 500 ± 1290 in the presence of a redox mediator. This work represents an example of a homogeneous biohybrid system combining polymer nanoparticles and an enzyme. Detailed spectroscopic studies provide a mechanistic understanding of light harvesting, charge separation, and transport studied, which is essential for building semiartificial photosynthetic systems with efficiencies beyond natural and artificial systems.
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Affiliation(s)
- Mariia V Pavliuk
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Marco Lorenzi
- Department of Chemistry─Ångström Laboratory, Molecular Biomimetics, Uppsala University, 751 20 Uppsala, Sweden
| | - Dustin R Morado
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, 171 65 Solna, Sweden
| | - Lars Gedda
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Sina Wrede
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Sara H Mejias
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Aijie Liu
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Moritz Senger
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Starla Glover
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Katarina Edwards
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
| | - Gustav Berggren
- Department of Chemistry─Ångström Laboratory, Molecular Biomimetics, Uppsala University, 751 20 Uppsala, Sweden
| | - Haining Tian
- Department of Chemistry─Ångström Laboratory, Physical Chemistry, Uppsala University, 751 20 Uppsala, Sweden
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12
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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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13
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Sanchez MK, Wiley S, Reijerse E, Lubitz W, Birrell JA, Dyer RB. Time-Resolved Infrared Spectroscopy Reveals the pH-Independence of the First Electron Transfer Step in the [FeFe] Hydrogenase Catalytic Cycle. J Phys Chem Lett 2022; 13:5986-5990. [PMID: 35736652 PMCID: PMC9251755 DOI: 10.1021/acs.jpclett.2c01467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
[FeFe] hydrogenases are highly active catalysts for hydrogen conversion. Their active site has two components: a [4Fe-4S] electron relay covalently attached to the H2 binding site and a diiron cluster ligated by CO, CN-, and 2-azapropane-1,3-dithiolate (ADT) ligands. Reduction of the [4Fe-4S] site was proposed to be coupled with protonation of one of its cysteine ligands. Here, we used time-resolved infrared (TRIR) spectroscopy on the [FeFe] hydrogenase from Chlamydomonas reinhardtii (CrHydA1) containing a propane-1,3-dithiolate (PDT) ligand instead of the native ADT ligand. The PDT modification does not affect the electron transfer step to [4Fe-4S]H but prevents the enzyme from proceeding further through the catalytic cycle. We show that the rate of the first electron transfer step is independent of the pH, supporting a simple electron transfer rather than a proton-coupled event. These results have important implications for our understanding of the catalytic mechanism of [FeFe] hydrogenases and highlight the utility of TRIR.
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Affiliation(s)
- Monica
L. K. Sanchez
- Department
of Chemistry and Biochemistry, Montana State
University, Bozeman, Montana 59717, United States
- Department
of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Seth Wiley
- Department
of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Edward Reijerse
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Wolfgang Lubitz
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - James A. Birrell
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - R. Brian Dyer
- Department
of Chemistry, Emory University, Atlanta, Georgia 30030, United States
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14
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Senger M, Duan J, Pavliuk MV, Apfel UP, Haumann M, Stripp ST. Trapping an Oxidized and Protonated Intermediate of the [FeFe]-Hydrogenase Cofactor under Mildly Reducing Conditions. Inorg Chem 2022; 61:10036-10042. [PMID: 35729755 DOI: 10.1021/acs.inorgchem.2c00954] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The H-cluster is the catalytic cofactor of [FeFe]-hydrogenase, a metalloenzyme that catalyzes the formation of dihydrogen (H2). The catalytic diiron site of the H-cluster carries two cyanide and three carbon monoxide ligands, making it an excellent target for IR spectroscopy. In previous work, we identified an oxidized and protonated H-cluster species, whose IR signature differs from that of the oxidized resting state (Hox) by a small but distinct shift to higher frequencies. This "blue shift" was explained by a protonation at the [4Fe-4S] subcomplex of the H-cluster. The novel species, denoted HoxH, was preferentially accumulated at low pH and in the presence of the exogenous reductant sodium dithionite (NaDT). When HoxH was reacted with H2, the hydride state (Hhyd) was formed, a key intermediate of [FeFe]-hydrogenase turnover. A recent publication revisited our protocol for the accumulation of HoxH in wild-type [FeFe]-hydrogenase, concluding that inhibition by NaDT decay products rather than cofactor protonation causes the spectroscopic "blue shift". Here, we demonstrate that HoxH formation does not require the presence of NaDT (or its decay products), but accumulates also with the milder reductants tris(2-carboxyethyl)phosphine, dithiothreitol, or ascorbic acid, in particular at low pH. Our data consistently suggest that HoxH is accumulated when deprotonation of the H-cluster is impaired, thereby preventing the regain of the oxidized resting state Hox in the catalytic cycle.
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Affiliation(s)
- Moritz Senger
- Department of Chemistry, Physical Chemistry, Uppsala University, Uppsala 75120, Sweden
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, Bochum 44801, Germany
| | - Mariia V Pavliuk
- Department of Chemistry, Physical Chemistry, Uppsala University, Uppsala 75120, Sweden
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Small Molecule Activation, Ruhr-Universität Bochum, Bochum 44801, Germany.,Electrosynthesis, Fraunhofer UMSICHT, Oberhausen 46047, Germany
| | - Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, Berlin 14195, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin 14195, Germany
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15
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Baserga F, Vorkas A, Crea F, Schubert L, Chen JL, Redlich A, La Greca M, Storm J, Oldemeyer S, Hoffmann K, Schlesinger R, Heberle J. Membrane Protein Activity Induces Specific Molecular Changes in Nanodiscs Monitored by FTIR Difference Spectroscopy. Front Mol Biosci 2022; 9:915328. [PMID: 35769914 PMCID: PMC9234331 DOI: 10.3389/fmolb.2022.915328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022] Open
Abstract
It is well known that lipids neighboring integral membrane proteins directly influence their function. The opposite effect is true as well, as membrane proteins undergo structural changes after activation and thus perturb the lipidic environment. Here, we studied the interaction between these molecular machines and the lipid bilayer by observing changes in the lipid vibrational bands via FTIR spectroscopy. Membrane proteins with different functionalities have been reconstituted into lipid nanodiscs: Microbial rhodopsins that act as light-activated ion pumps (the proton pumps NsXeR and UmRh1, and the chloride pump NmHR) or as sensors (NpSRII), as well as the electron-driven cytochrome c oxidase RsCcO. The effects of the structural changes on the surrounding lipid phase are compared to mechanically induced lateral tension exerted by the light-activatable lipid analogue AzoPC. With the help of isotopologues, we show that the ν(C = O) ester band of the glycerol backbone reports on changes in the lipids’ collective state induced by mechanical changes in the transmembrane proteins. The perturbation of the nanodisc lipids seems to involve their phase and/or packing state. 13C-labeling of the scaffold protein shows that its structure also responds to the mechanical expansion of the lipid bilayer.
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Affiliation(s)
- Federico Baserga
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Antreas Vorkas
- Department of Physics, Genetic Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Fucsia Crea
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Luiz Schubert
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Jheng-Liang Chen
- Department of Physics, Genetic Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Aoife Redlich
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | | | - Julian Storm
- Department of Physics, Genetic Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Sabine Oldemeyer
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Kirsten Hoffmann
- Department of Physics, Genetic Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Ramona Schlesinger
- Department of Physics, Genetic Biophysics, Freie Universität Berlin, Berlin, Germany
- *Correspondence: Ramona Schlesinger, ; Joachim Heberle,
| | - Joachim Heberle
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
- *Correspondence: Ramona Schlesinger, ; Joachim Heberle,
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16
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Ahmed ME, Nayek A, Križan A, Coutard N, Morozan A, Ghosh Dey S, Lomoth R, Hammarström L, Artero V, Dey A. A Bidirectional Bioinspired [FeFe]-Hydrogenase Model. J Am Chem Soc 2022; 144:3614-3625. [DOI: 10.1021/jacs.1c12605] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Md Estak Ahmed
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, India 700032
| | - Abhijit Nayek
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, India 700032
| | - Alenka Križan
- Department of Chemistry- Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Nathan Coutard
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, 38000 Grenoble, France
| | - Adina Morozan
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, 38000 Grenoble, France
| | - Somdatta Ghosh Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, India 700032
| | - Reiner Lomoth
- Department of Chemistry- Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Leif Hammarström
- Department of Chemistry- Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Vincent Artero
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, 38000 Grenoble, France
| | - Abhishek Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, India 700032
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17
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Senger M, Kernmayr T, Lorenzi M, Redman HJ, Berggren G. Hydride state accumulation in native [FeFe]-hydrogenase with the physiological reductant H2 supports its catalytic relevance. Chem Commun (Camb) 2022; 58:7184-7187. [PMID: 35670542 PMCID: PMC9219605 DOI: 10.1039/d2cc00671e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Small molecules in solution may interfere with mechanistic investigations, as they can affect the stability of catalytic states and produce off-cycle states that can be mistaken for catalytically relevant species. Here we show that the hydride state (Hhyd), a proposed central intermediate in the catalytic cycle of [FeFe]-hydrogenase, can be formed in wild-type [FeFe]-hydrogenases treated with H2 in absence of other, non-biological, reductants. Moreover, we reveal a new state with unclear role in catalysis induced by common low pH buffers. Studies of enzymatic catalysis often rely on non-biological reagents, which may affect catalytic intermediates and produce off-cycle states. Here the influence of buffer and reductant on key intermediates of [FeFe]-hydrogenase are explored.![]()
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Affiliation(s)
- Moritz Senger
- Department of Chemistry, Physical Chemistry, Uppsala University, 75120 Uppsala, Sweden.
| | - Tobias Kernmayr
- Department of Chemistry, Molecular Biomimetics, Uppsala University, 75120 Uppsala, Sweden.
| | - Marco Lorenzi
- Department of Chemistry, Molecular Biomimetics, Uppsala University, 75120 Uppsala, Sweden.
| | - Holly J Redman
- Department of Chemistry, Molecular Biomimetics, Uppsala University, 75120 Uppsala, Sweden.
| | - Gustav Berggren
- Department of Chemistry, Molecular Biomimetics, Uppsala University, 75120 Uppsala, Sweden.
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18
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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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19
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Martini MA, Rüdiger O, Breuer N, Nöring B, DeBeer S, Rodríguez-Maciá P, Birrell JA. The Nonphysiological Reductant Sodium Dithionite and [FeFe] Hydrogenase: Influence on the Enzyme Mechanism. J Am Chem Soc 2021; 143:18159-18171. [PMID: 34668697 PMCID: PMC8569811 DOI: 10.1021/jacs.1c07322] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[FeFe] hydrogenases are highly active enzymes for interconverting protons and electrons with hydrogen (H2). Their active site H-cluster is formed of a canonical [4Fe-4S] cluster ([4Fe-4S]H) covalently attached to a unique [2Fe] subcluster ([2Fe]H), where both sites are redox active. Heterolytic splitting and formation of H2 takes place at [2Fe]H, while [4Fe-4S]H stores electrons. The detailed catalytic mechanism of these enzymes is under intense investigation, with two dominant models existing in the literature. In one model, an alternative form of the active oxidized state Hox, named HoxH, which forms at low pH in the presence of the nonphysiological reductant sodium dithionite (NaDT), is believed to play a crucial role. HoxH was previously suggested to have a protonated [4Fe-4S]H. Here, we show that HoxH forms by simple addition of sodium sulfite (Na2SO3, the dominant oxidation product of NaDT) at low pH. The low pH requirement indicates that sulfur dioxide (SO2) is the species involved. Spectroscopy supports binding at or near [4Fe-4S]H, causing its redox potential to increase by ∼60 mV. This potential shift detunes the redox potentials of the subclusters of the H-cluster, lowering activity, as shown in protein film electrochemistry (PFE). Together, these results indicate that HoxH and its one-electron reduced counterpart Hred'H are artifacts of using a nonphysiological reductant, and not crucial catalytic intermediates. We propose renaming these states as the "dithionite (DT) inhibited" states Hox-DTi and Hred-DTi. The broader potential implications of using a nonphysiological reductant in spectroscopic and mechanistic studies of enzymes are highlighted.
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Affiliation(s)
- Maria Alessandra Martini
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Olaf Rüdiger
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Nina Breuer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Birgit Nöring
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Patricia Rodríguez-Maciá
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, U.K
| | - James A Birrell
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
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20
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Morra S, Duan J, Winkler M, Ash PA, Happe T, Vincent KA. Electrochemical control of [FeFe]-hydrogenase single crystals reveals complex redox populations at the catalytic site. Dalton Trans 2021; 50:12655-12663. [PMID: 34545877 PMCID: PMC8453692 DOI: 10.1039/d1dt02219a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022]
Abstract
Elucidating the distribution of intermediates at the active site of redox metalloenzymes is vital to understanding their highly efficient catalysis. Here we demonstrate that it is possible to generate, and detect, the key catalytic redox states of an [FeFe]-hydrogenase in a protein crystal. Individual crystals of the prototypical [FeFe]-hydrogenase I from Clostridium pasteurianum (CpI) are maintained under electrochemical control, allowing for precise tuning of the redox potential, while the crystal is simultaneously probed via Fourier Transform Infrared (FTIR) microspectroscopy. The high signal/noise spectra reveal potential-dependent variation in the distribution of redox states at the active site (H-cluster) according to state-specific vibrational bands from the endogeneous CO and CN- ligands. CpI crystals are shown to populate the same H-cluster states as those detected in solution, including the oxidised species Hox, the reduced species Hred/HredH+, the super-reduced HsredH+ and the hydride species Hhyd. The high sensitivity and precise redox control offered by this approach also facilitates the detection and characterisation of low abundance species that only accumulate within a narrow window of conditions, revealing new redox intermediates.
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Affiliation(s)
- Simone Morra
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom.
| | - Jifu Duan
- Faculty of Biology and Biotechnology, AG Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Martin Winkler
- Faculty of Biology and Biotechnology, AG Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Philip A Ash
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom.
| | - Thomas Happe
- Faculty of Biology and Biotechnology, AG Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom.
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21
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Electron inventory of the iron-sulfur scaffold complex HypCD essential in [NiFe]-hydrogenase cofactor assembly. Biochem J 2021; 478:3281-3295. [PMID: 34409988 PMCID: PMC8454700 DOI: 10.1042/bcj20210224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 11/17/2022]
Abstract
The [4Fe-4S] cluster containing scaffold complex HypCD is the central construction site for the assembly of the [Fe](CN)2CO cofactor precursor of [NiFe]-hydrogenase. While the importance of the HypCD complex is well established, not much is known about the mechanism by which the CN- and CO ligands are transferred and attached to the iron ion. We report an efficient expression and purification system producing the HypCD complex from E. coli with complete metal content. This enabled in-depth spectroscopic characterizations. The results obtained by EPR and Mössbauer spectroscopy demonstrate that the [Fe](CN)2CO cofactor and the [4Fe-4S] cluster of the HypCD complex are redox active. The data indicate a potential-dependent interconversion of the [Fe]2+/3+ and [4Fe-4S]2+/+ couple, respectively. Moreover, ATR FTIR spectroscopy reveals potential-dependent disulfide formation, which hints at an electron confurcation step between the metal centers. MicroScale thermophoresis indicates preferable binding between the HypCD complex and its in vivo interaction partner HypE under reducing conditions. Together, these results provide comprehensive evidence for an electron inventory fit to drive multi-electron redox reactions required for the assembly of the CN- and CO ligands on the scaffold complex HypCD.
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22
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Torres A, Collado A, Gómez-Gallego M, Ramírez de Arellano C, Sierra MA. Electrocatalytic Behavior of Tetrathiafulvalene (TTF) and Extended Tetrathiafulvalene (exTTF) [FeFe] Hydrogenase Mimics. ACS ORGANIC & INORGANIC AU 2021; 2:23-33. [PMID: 36855407 PMCID: PMC9954209 DOI: 10.1021/acsorginorgau.1c00011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
TTF- and exTTF-containing [(μ-S2)Fe2(CO)6] complexes have been prepared by the photochemical reaction of TTF or exTTF and [(μ-S2)Fe2(CO)6]. These complexes are able to interact with PAHs. In the absence of air and in acid media an electrocatalytic dihydrogen evolution reaction (HER) occurs, similarly to analogous [(μ-S2)Fe2(CO)6] complexes. However, in the presence of air, the TTF and exTTF organic moieties strongly influence the electrochemistry of these systems. The reported data may be valuable in the design of [FeFe] hydrogenase mimics able to combine the HER properties of the [FeFe] cores with the unique TTF properties.
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Affiliation(s)
- Alejandro Torres
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain,Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - Alba Collado
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain,Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - Mar Gómez-Gallego
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain,Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - Carmen Ramírez de Arellano
- Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain,Departamento
de Química Orgánica, Universidad
de Valencia, 46100 Valencia, Spain
| | - Miguel A. Sierra
- Departamento
de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain,Center
for Innovation in Advanced Chemistry (ORFEO-CINQA), Facultad de Química, Universidad Complutense, 28040 Madrid, Spain,Email for M.A.S.:
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23
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Affiliation(s)
- Sven T. Stripp
- Freie Universität Berlin, Department of Physics, Arnimallee 14, 14195 Berlin, Germany
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24
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Rohde M, Laun K, Zebger I, Stripp ST, Einsle O. Two ligand-binding sites in CO-reducing V nitrogenase reveal a general mechanistic principle. SCIENCE ADVANCES 2021; 7:7/22/eabg4474. [PMID: 34049880 PMCID: PMC8163085 DOI: 10.1126/sciadv.abg4474] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
Besides its role in biological nitrogen fixation, vanadium-containing nitrogenase also reduces carbon monoxide (CO) to hydrocarbons, in analogy to the industrial Fischer-Tropsch process. The protein yields 93% of ethylene (C2H4), implying a C-C coupling step that mandates the simultaneous binding of two CO at the active site FeV cofactor. Spectroscopic data indicated multiple CO binding events, but structural analyses of Mo and V nitrogenase only confirmed a single site. Here, we report the structure of a two CO-bound state of V nitrogenase at 1.05 Å resolution, with one μ-bridging and one terminal CO molecule. This additional, specific ligand binding site suggests a mechanistic route for CO reduction and hydrocarbon formation, as well as a second access pathway for protons required during the reaction. Moreover, carbonyls are strong-field ligands that are chemically similar to mechanistically relevant hydrides that may be formed and used in a fully analogous fashion.
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Affiliation(s)
- Michael Rohde
- Institute for Biochemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Konstantin Laun
- Institute of Chemistry, Technical University of Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Ingo Zebger
- Institute of Chemistry, Technical University of Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Sven T Stripp
- Institute of Experimental Physics, Department of Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Oliver Einsle
- Institute for Biochemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
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25
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Laun K, Baranova I, Duan J, Kertess L, Wittkamp F, Apfel UP, Happe T, Senger M, Stripp ST. Site-selective protonation of the one-electron reduced cofactor in [FeFe]-hydrogenase. Dalton Trans 2021; 50:3641-3650. [PMID: 33629081 DOI: 10.1039/d1dt00110h] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogenases are bidirectional redox enzymes that catalyze hydrogen turnover in archaea, bacteria, and algae. While all types of hydrogenase show H2 oxidation activity, [FeFe]-hydrogenases are excellent H2 evolution catalysts as well. Their active site cofactor comprises a [4Fe-4S] cluster covalently linked to a diiron site equipped with carbon monoxide and cyanide ligands. The active site niche is connected with the solvent by two distinct proton transfer pathways. To analyze the catalytic mechanism of [FeFe]-hydrogenase, we employ operando infrared spectroscopy and infrared spectro-electrochemistry. Titrating the pH under H2 oxidation or H2 evolution conditions reveals the influence of site-selective protonation on the equilibrium of reduced cofactor states. Governed by pKa differences across the active site niche and proton transfer pathways, we find that individual electrons are stabilized either at the [4Fe-4S] cluster (alkaline pH values) or at the diiron site (acidic pH values). This observation is discussed in the context of the complex interdependence of hydrogen turnover and bulk pH.
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Affiliation(s)
- Konstantin Laun
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin and Department of Chemistry, Technische Universität Berlin, 10623 Berlin, Germany
| | - Iuliia Baranova
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin and Faculty of Physics, St. Petersburg State University, 198504 St. Petersburg, Russian Federation
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Leonie Kertess
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany and Fraunhofer UMSICHT, 46047 Oberhausen, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Moritz Senger
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin and Department of Chemistry, Uppsala University, 75120 Uppsala, Sweden.
| | - Sven T Stripp
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin
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26
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Abstract
[FeFe]-hydrogenases are efficient H2-catalysts, yet upon contact with dioxygen their catalytic cofactor (H-cluster) is irreversibly inactivated. Here, we combine X-ray crystallography, rational protein design, direct electrochemistry, and Fourier-transform infrared spectroscopy to describe a protein morphing mechanism that controls the reversible transition between the catalytic Hox-state and the inactive but oxygen-resistant Hinact-state in [FeFe]-hydrogenase CbA5H of Clostridium beijerinckii. The X-ray structure of air-exposed CbA5H reveals that a conserved cysteine residue in the local environment of the active site (H-cluster) directly coordinates the substrate-binding site, providing a safety cap that prevents O2-binding and consequently, cofactor degradation. This protection mechanism depends on three non-conserved amino acids situated approximately 13 Å away from the H-cluster, demonstrating that the 1st coordination sphere chemistry of the H-cluster can be remote-controlled by distant residues.
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Abstract
Hydrogenases are metalloenzymes that catalyze proton reduction and H2 oxidation with outstanding efficiency. They are model systems for bioinorganic chemistry, including low-valent transition metals, hydride chemistry, and proton-coupled electron transfer. In this Account, we describe how photochemistry and infrared difference spectroscopy can be used to identify the dynamic hydrogen-bonding changes that facilitate proton transfer in [NiFe]- and [FeFe]-hydrogenase.[NiFe]-hydrogenase binds a heterobimetallic nickel/iron site embedded in the protein by four cysteine ligands. [FeFe]-hydrogenase carries a homobimetallic iron/iron site attached to the protein by only a single cysteine. Carbon monoxide and cyanide ligands in the active site facilitate detailed investigations of hydrogenase catalysis by infrared spectroscopy because of their strong signals and redox-dependent frequency shifts. We found that specific redox-state transitions in [NiFe]- and [FeFe]-hydrogenase can be triggered by visible light to record extremely sensitive "light-minus-dark" infrared difference spectra monitoring key amino acid residues. As these transitions are coupled to protonation changes, our data allowed investigation of dynamic hydrogen-bonding changes that go well beyond the resolution of protein crystallography.In [NiFe]-hydrogenase, photolysis of the bridging hydride ligand in the Ni-C state was followed by infrared difference spectroscopy. Our data clearly indicate the formation of a protonated cysteine residue as well as hydrogen-bonding changes involving a glutamic acid residue and a "dangling water" molecule. These findings are in excellent agreement with crystallographic analyses of [NiFe]-hydrogenase. In [FeFe]-hydrogenase, an external redox dye was used to accumulate the Hred state. Infrared difference spectra indicate hydrogen-bonding changes involving two glutamic acid residues and a conserved arginine residue. While crystallographic analyses of [FeFe]-hydrogenase in the oxidized state failed to explain the rapid proton transfer because of a breach in the succession of residues, our findings facilitated a precise molecular model of discontinued proton transfer.Comparing both systems, our data emphasize the role of the outer coordination sphere in bimetallic hydrogenases: we suggest that protonation of a nickel-ligating cysteine in [NiFe]-hydrogenase causes the notable preference toward H2 oxidation. On the contrary, proton transfer in [FeFe]-hydrogenase involves an adjacent cysteine as a relay group, promoting both H2 oxidation and proton reduction. These observations may guide the design of organometallic compounds that mimic the catalytic properties of hydrogenases.
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Affiliation(s)
- Hulin Tai
- Department of Chemistry, National Demonstration Centre for Experimental Chemistry Education, Yanbian University, Yanji, Jilin 133002, China
| | - Shun Hirota
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Sven T. Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
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28
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Kleinhaus JT, Wittkamp F, Yadav S, Siegmund D, Apfel UP. [FeFe]-Hydrogenases: maturation and reactivity of enzymatic systems and overview of biomimetic models. Chem Soc Rev 2021; 50:1668-1784. [DOI: 10.1039/d0cs01089h] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
[FeFe]-hydrogenases recieved increasing interest in the last decades. This review summarises important findings regarding their enzymatic reactivity as well as inorganic models applied as electro- and photochemical catalysts.
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Affiliation(s)
| | | | - Shanika Yadav
- Inorganic Chemistry I
- Ruhr University Bochum
- 44801 Bochum
- Germany
| | - Daniel Siegmund
- Department of Electrosynthesis
- Fraunhofer UMSICHT
- 46047 Oberhausen
- Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I
- Ruhr University Bochum
- 44801 Bochum
- Germany
- Department of Electrosynthesis
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29
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Amanullah S, Saha P, Nayek A, Ahmed ME, Dey A. Biochemical and artificial pathways for the reduction of carbon dioxide, nitrite and the competing proton reduction: effect of 2nd sphere interactions in catalysis. Chem Soc Rev 2021; 50:3755-3823. [DOI: 10.1039/d0cs01405b] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Reduction of oxides and oxoanions of carbon and nitrogen are of great contemporary importance as they are crucial for a sustainable environment.
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Affiliation(s)
- Sk Amanullah
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Paramita Saha
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Abhijit Nayek
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Md Estak Ahmed
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Abhishek Dey
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
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30
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Stripp ST, Mebs S, Haumann M. Temperature Dependence of Structural Dynamics at the Catalytic Cofactor of [FeFe]-hydrogenase. Inorg Chem 2020; 59:16474-16488. [PMID: 33147959 DOI: 10.1021/acs.inorgchem.0c02316] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
[FeFe]-hydrogenases are nature's blueprint for efficient hydrogen turnover. Understanding their enzymatic mechanism may improve technological H2 fuel generation. The active-site cofactor (H-cluster) consists of a [4Fe-4S] cluster ([4Fe]H), cysteine-linked to a diiron site ([2Fe]H) carrying an azadithiolate (adt) group, terminal cyanide and carbon monoxide ligands, and a bridging carbon monoxide (μCO) in the oxidized protein (Hox). Recently, the debate on the structure of reduced H-cluster states was intensified by the assignment of new species under cryogenic conditions. We investigated temperature effects (4-280 K) in infrared (IR) and X-ray absorption spectroscopy (XAS) data of [FeFe]-hydrogenases using fit analyses and quantum-chemical calculations. IR data from our laboratory and literature sources were evaluated. At ambient temperatures, reduced H-cluster states with a bridging hydride (μH-, in Hred and Hsred) or with an additional proton at [4Fe]H (Hred') or at the distal iron of [2Fe]H (Hhyd) prevail. At cryogenic temperatures, these species are largely replaced by states that hold a μCO, lack [4Fe]H protonation, and bind an additional proton at the adt nitrogen (HredH+ and HsredH+). XAS revealed the atomic coordinate dispersion (i.e., the Debye-Waller parameter, 2σ2) of the iron-ligand bonds and Fe-Fe distances in the oxidized and reduced H-cluster. 2σ2 showed a temperature dependence typical for the so-called protein-glass transition, with small changes below ∼200 K and a pronounced increase above this "breakpoint". This behavior is attributed to the freezing-out of larger-scale anharmonic motions of amino acid side chains and water species. We propose that protonation at [4Fe]H as well as ligand rearrangement and μH- binding at [2Fe]H are impaired because of restricted molecular mobility at cryogenic temperatures so that protonation can be biased toward adt. We conclude that a H-cluster with a μCO, selective [4Fe]H or [2Fe]H protonation, and catalytic proton transfer via adt facilitates efficient H2 conversion in [FeFe]-hydrogenase.
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Affiliation(s)
- Sven T Stripp
- Physics Department, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Stefan Mebs
- Physics Department, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Michael Haumann
- Physics Department, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
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31
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Rodríguez-Maciá P, Breuer N, DeBeer S, Birrell JA. Insight into the Redox Behavior of the [4Fe–4S] Subcluster in [FeFe] Hydrogenases. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02771] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Patricia Rodríguez-Maciá
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany
| | - Nina Breuer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany
| | - Serena DeBeer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany
| | - James A. Birrell
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany
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32
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Sanchez MLK, Konecny SE, Narehood SM, Reijerse EJ, Lubitz W, Birrell JA, Dyer RB. The Laser-Induced Potential Jump: A Method for Rapid Electron Injection into Oxidoreductase Enzymes. J Phys Chem B 2020; 124:8750-8760. [PMID: 32924491 DOI: 10.1021/acs.jpcb.0c05718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxidoreductase enzymes often perform technologically useful chemical transformations using abundant metal cofactors with high efficiency under ambient conditions. The understanding of the catalytic mechanism of these enzymes is, however, highly dependent on the availability of well-characterized and optimized time-resolved analytical techniques. We have developed an approach for rapidly injecting electrons into a catalytic system using a photoactivated nanomaterial in combination with a range of redox mediators to produce a potential jump in solution, which then initiates turnover via electron transfer (ET) to the catalyst. The ET events at the nanomaterial-mediator-catalyst interfaces are, however, highly sensitive to the experimental conditions such as photon flux, relative concentrations of system components, and pH. Here, we present a systematic optimization of these experimental parameters for a specific catalytic system, namely, [FeFe] hydrogenase from Chlamydomonas reinhardtii (CrHydA1). The developed strategies can, however, be applied in the study of a wide variety of oxidoreductase enzymes. Our potential jump system consists of CdSe/CdS core-shell nanorods as a photosensitizer and a series of substituted bipyridinium salts as mediators with redox potentials in the range from -550 to -670 mV (vs SHE). With these components, we screened the effect of pH, mediator concentration, protein concentration, photosensitizer concentration, and photon flux on steady-state photoreduction and hydrogen production as well as ET and potential jump efficiency. By manipulating these experimental conditions, we show the potential of simple modifications to improve the tunability of the potential jump for application to study oxidoreductases.
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Affiliation(s)
- Monica L K Sanchez
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Sara E Konecny
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Sarah M Narehood
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Edward J Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - James A Birrell
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - R Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
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33
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Land H, Sekretareva A, Huang P, Redman HJ, Németh B, Polidori N, Mészáros LS, Senger M, Stripp ST, Berggren G. Characterization of a putative sensory [FeFe]-hydrogenase provides new insight into the role of the active site architecture. Chem Sci 2020; 11:12789-12801. [PMID: 34094474 PMCID: PMC8163306 DOI: 10.1039/d0sc03319g] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/19/2020] [Indexed: 12/12/2022] Open
Abstract
[FeFe]-hydrogenases are known for their high rates of hydrogen turnover, and are intensively studied in the context of biotechnological applications. Evolution has generated a plethora of different subclasses with widely different characteristics. The M2e subclass is phylogenetically distinct from previously characterized members of this enzyme family and its biological role is unknown. It features significant differences in domain- and active site architecture, and is most closely related to the putative sensory [FeFe]-hydrogenases. Here we report the first comprehensive biochemical and spectroscopical characterization of an M2e enzyme, derived from Thermoanaerobacter mathranii. As compared to other [FeFe]-hydrogenases characterized to-date, this enzyme displays an increased H2 affinity, higher activation enthalpies for H+/H2 interconversion, and unusual reactivity towards known hydrogenase inhibitors. These properties are related to differences in active site architecture between the M2e [FeFe]-hydrogenase and "prototypical" [FeFe]-hydrogenases. Thus, this study provides new insight into the role of this subclass in hydrogen metabolism and the influence of the active site pocket on the chemistry of the H-cluster.
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Affiliation(s)
- Henrik Land
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Alina Sekretareva
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Ping Huang
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Holly J Redman
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Brigitta Németh
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Nakia Polidori
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Lívia S Mészáros
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Moritz Senger
- Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin Arnimallee 14 DE-14195 Berlin Germany
| | - Sven T Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin Arnimallee 14 DE-14195 Berlin Germany
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
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34
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The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases. Proc Natl Acad Sci U S A 2020; 117:20520-20529. [PMID: 32796105 DOI: 10.1073/pnas.2007090117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
As paradigms for proton-coupled electron transfer in enzymes and benchmarks for a fully renewable H2 technology, [FeFe]-hydrogenases behave as highly reversible electrocatalysts when immobilized on an electrode, operating in both catalytic directions with minimal overpotential requirement. Using the [FeFe]-hydrogenases from Clostridium pasteurianum (CpI) and Chlamydomonas reinhardtii (CrHydA1) we have conducted site-directed mutagenesis and protein film electrochemistry to determine how efficient catalysis depends on the long-range coupling of electron and proton transfer steps. Importantly, the electron and proton transfer pathways in [FeFe]-hydrogenases are well separated from each other in space. Variants with conservative substitutions (glutamate to aspartate) in either of two positions in the proton-transfer pathway retain significant activity and reveal the consequences of slowing down proton transfer for both catalytic directions over a wide range of pH and potential values. Proton reduction in the variants is impaired mainly by limiting the turnover rate, which drops sharply as the pH is raised, showing that proton capture from bulk solvent becomes critical. In contrast, hydrogen oxidation is affected in two ways: by limiting the turnover rate and by a large overpotential requirement that increases as the pH is raised, consistent with the accumulation of a reduced and protonated intermediate. A unique observation having fundamental significance is made under conditions where the variants still retain sufficient catalytic activity in both directions: An inflection appears as the catalytic current switches direction at the 2H+/H2 thermodynamic potential, clearly signaling a departure from electrocatalytic reversibility as electron and proton transfers begin to be decoupled.
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35
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Németh B, Senger M, Redman HJ, Ceccaldi P, Broderick J, Magnuson A, Stripp ST, Haumann M, Berggren G. [FeFe]-hydrogenase maturation: H-cluster assembly intermediates tracked by electron paramagnetic resonance, infrared, and X-ray absorption spectroscopy. J Biol Inorg Chem 2020; 25:777-788. [PMID: 32661785 PMCID: PMC7399679 DOI: 10.1007/s00775-020-01799-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/09/2020] [Indexed: 11/25/2022]
Abstract
[FeFe]-hydrogenase enzymes employ a unique organometallic cofactor for efficient and reversible hydrogen conversion. This so-called H-cluster consists of a [4Fe-4S] cubane cysteine linked to a diiron complex coordinated by carbon monoxide and cyanide ligands and an azadithiolate ligand (adt = NH(CH2S)2)·[FeFe]-hydrogenase apo-protein binding only the [4Fe-4S] sub-complex can be fully activated in vitro by the addition of a synthetic diiron site precursor complex ([2Fe]adt). Elucidation of the mechanism of cofactor assembly will aid in the design of improved hydrogen processing synthetic catalysts. We combined electron paramagnetic resonance, Fourier-transform infrared, and X-ray absorption spectroscopy to characterize intermediates of H-cluster assembly as initiated by mixing of the apo-protein (HydA1) from the green alga Chlamydomonas reinhardtii with [2Fe]adt. The three methods consistently show rapid formation of a complete H-cluster in the oxidized, CO-inhibited state (Hox-CO) already within seconds after the mixing. Moreover, FTIR spectroscopy support a model in which Hox-CO formation is preceded by a short-lived Hred'-CO-like intermediate. Accumulation of Hox-CO was followed by CO release resulting in the slower conversion to the catalytically active state (Hox) as well as formation of reduced states of the H-cluster.
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Affiliation(s)
- Brigitta Németh
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Moritz Senger
- Physics Department, Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
- Department of Chemistry, Ångström Laboratory, Physical Chemistry, Uppsala University, 75120, Uppsala, Sweden
| | - Holly J Redman
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Pierre Ceccaldi
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Joan Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Ann Magnuson
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Sven T Stripp
- Physics Department, Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
| | - Michael Haumann
- Physics Department, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195, Berlin, Germany
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden.
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36
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Land H, Senger M, Berggren G, Stripp ST. Current State of [FeFe]-Hydrogenase Research: Biodiversity and Spectroscopic Investigations. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01614] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Henrik Land
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
| | - Moritz Senger
- Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
| | - Sven T. Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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37
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Abstract
[FeFe]-hydrogenases have attracted research for more than twenty years as paragons for the design of new catalysts for the hydrogen evolution reaction (HER). The bridging dithiolate comprising a secondary amine as bridgehead is the key element for the reactivity of native [FeFe]-hydrogenases and was therefore the midpoint of hundreds of biomimetic hydrogenase models. However, within those mimics, phosphorous is barely seen as a central element in the azadithiolato bridge despite being the direct heavier homologue of nitrogen. We herein synthesized three new phosphorous based [FeFe]-hydrogenase models by reacting dithiols (HSCH2)2P(O)R (R = Me, OEt, OPh) with Fe3(CO)12. All synthesized mimics show catalytic reactivity regarding HER and change their mechanisms depending on the strength of the used acid. In all presented mimics, the oxide is the center of reactivity, independent of the nature of the bridgehead. However, the phosphorous atom might be reduced by the methods we present herein to alter the reactivity of the model compounds towards protons and oxygen.
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38
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Mészáros LS, Ceccaldi P, Lorenzi M, Redman HJ, Pfitzner E, Heberle J, Senger M, Stripp ST, Berggren G. Spectroscopic investigations under whole-cell conditions provide new insight into the metal hydride chemistry of [FeFe]-hydrogenase. Chem Sci 2020; 11:4608-4617. [PMID: 34122916 PMCID: PMC8159234 DOI: 10.1039/d0sc00512f] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Hydrogenases are among the fastest H2 evolving catalysts known to date and have been extensively studied under in vitro conditions. Here, we report the first mechanistic investigation of an [FeFe]-hydrogenase under whole-cell conditions. Functional [FeFe]-hydrogenase from the green alga Chlamydomonas reinhardtii is generated in genetically modified Escherichia coli cells by addition of a synthetic cofactor to the growth medium. The assembly and reactivity of the resulting semi-synthetic enzyme was monitored using whole-cell electron paramagnetic resonance and Fourier-transform Infrared difference spectroscopy as well as scattering scanning near-field optical microscopy. Through a combination of gas treatments, pH titrations, and isotope editing we were able to corroborate the formation of a number of proposed catalytic intermediates in living cells, supporting their physiological relevance. Moreover, a previously incompletely characterized catalytic intermediate is reported herein, attributed to the formation of a protonated metal hydride species.
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Affiliation(s)
- Lívia S Mészáros
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Pierre Ceccaldi
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Marco Lorenzi
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Holly J Redman
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Emanuel Pfitzner
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Joachim Heberle
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Moritz Senger
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Sven T Stripp
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Gustav Berggren
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
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39
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Abstract
Infrared difference spectroscopy probes vibrational changes of proteins upon their perturbation. Compared with other spectroscopic methods, it stands out by its sensitivity to the protonation state, H-bonding, and the conformation of different groups in proteins, including the peptide backbone, amino acid side chains, internal water molecules, or cofactors. In particular, the detection of protonation and H-bonding changes in a time-resolved manner, not easily obtained by other techniques, is one of the most successful applications of IR difference spectroscopy. The present review deals with the use of perturbations designed to specifically change the protein between two (or more) functionally relevant states, a strategy often referred to as reaction-induced IR difference spectroscopy. In the first half of this contribution, I review the technique of reaction-induced IR difference spectroscopy of proteins, with special emphasis given to the preparation of suitable samples and their characterization, strategies for the perturbation of proteins, and methodologies for time-resolved measurements (from nanoseconds to minutes). The second half of this contribution focuses on the spectral interpretation. It starts by reviewing how changes in H-bonding, medium polarity, and vibrational coupling affect vibrational frequencies, intensities, and bandwidths. It is followed by band assignments, a crucial aspect mostly performed with the help of isotopic labeling and site-directed mutagenesis, and complemented by integration and interpretation of the results in the context of the studied protein, an aspect increasingly supported by spectral calculations. Selected examples from the literature, predominately but not exclusively from retinal proteins, are used to illustrate the topics covered in this review.
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40
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Lorent C, Katz S, Duan J, Kulka CJ, Caserta G, Teutloff C, Yadav S, Apfel UP, Winkler M, Happe T, Horch M, Zebger I. Shedding Light on Proton and Electron Dynamics in [FeFe] Hydrogenases. J Am Chem Soc 2020; 142:5493-5497. [DOI: 10.1021/jacs.9b13075] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Christian Lorent
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Sagie Katz
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Catharina Julia Kulka
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Giorgio Caserta
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Christian Teutloff
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Shanika Yadav
- Inorganic Chemistry I, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
- Department of Energy, Electrosynthesis Group, Fraunhofer UMSICHT, Osterfelder Straße 3, 46047 Oberhausen, Germany
| | - Martin Winkler
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Marius Horch
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
- Department of Chemistry and York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, U.K
| | - Ingo Zebger
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
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41
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Artz JH, Zadvornyy OA, Mulder DW, Keable SM, Cohen AE, Ratzloff MW, Williams SG, Ginovska B, Kumar N, Song J, McPhillips SE, Davidson CM, Lyubimov AY, Pence N, Schut GJ, Jones AK, Soltis SM, Adams MWW, Raugei S, King PW, Peters JW. Tuning Catalytic Bias of Hydrogen Gas Producing Hydrogenases. J Am Chem Soc 2019; 142:1227-1235. [PMID: 31816235 PMCID: PMC8653774 DOI: 10.1021/jacs.9b08756] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrogenases display a wide range of catalytic rates and biases in reversible hydrogen gas oxidation catalysis. The interactions of the iron-sulfur-containing catalytic site with the local protein environment are thought to contribute to differences in catalytic reactivity, but this has not been demonstrated. The microbe Clostridium pasteurianum produces three [FeFe]-hydrogenases that differ in "catalytic bias" by exerting a disproportionate rate acceleration in one direction or the other that spans a remarkable 6 orders of magnitude. The combination of high-resolution structural work, biochemical analyses, and computational modeling indicates that protein secondary interactions directly influence the relative stabilization/destabilization of different oxidation states of the active site metal cluster. This selective stabilization or destabilization of oxidation states can preferentially promote hydrogen oxidation or proton reduction and represents a simple yet elegant model by which a protein catalytic site can confer catalytic bias.
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Affiliation(s)
- Jacob H. Artz
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, United States
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Oleg A. Zadvornyy
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - David W. Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Stephen M. Keable
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Aina E. Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Michael W. Ratzloff
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - S. Garrett Williams
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Bojana Ginovska
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Neeraj Kumar
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Jinhu Song
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Scott E. McPhillips
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Catherine M. Davidson
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Artem Y. Lyubimov
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Natasha Pence
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - Gerrit J. Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Anne K. Jones
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - S. Michael Soltis
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Simone Raugei
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, United States
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Paul W. King
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - John W. Peters
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, United States
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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42
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Mebs S, Srinivas V, Kositzki R, Griese JJ, Högbom M, Haumann M. Fate of oxygen species from O 2 activation at dimetal cofactors in an oxidase enzyme revealed by 57Fe nuclear resonance X-ray scattering and quantum chemistry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148060. [PMID: 31394094 DOI: 10.1016/j.bbabio.2019.148060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 10/26/2022]
Abstract
Oxygen (O2) activation is a central challenge in chemistry and catalyzed at prototypic dimetal cofactors in biological enzymes with diverse functions. Analysis of intermediates is required to elucidate the reaction paths of reductive O2 cleavage. An oxidase protein from the bacterium Geobacillus kaustophilus, R2lox, was used for aerobic in-vitro reconstitution with only 57Fe(II) or Mn(II) plus 57Fe(II) ions to yield [FeFe] or [MnFe] cofactors under various oxygen and solvent isotopic conditions including 16/18O and H/D exchange. 57Fe-specific X-ray scattering techniques were employed to collect nuclear forward scattering (NFS) and nuclear resonance vibrational spectroscopy (NRVS) data of the R2lox proteins. NFS revealed Fe/Mn(III)Fe(III) cofactor states and Mössbauer quadrupole splitting energies. Quantum chemical calculations of NRVS spectra assigned molecular structures, vibrational modes, and protonation patterns of the cofactors, featuring a terminal water (H2O) bound at iron or manganese in site 1 and a metal-bridging hydroxide (μOH-) ligand. A procedure for quantitation and correlation of experimental and computational NRVS difference signals due to isotope labeling was developed. This approach revealed that the protons of the ligands as well as the terminal water at the R2lox cofactors exchange with the bulk solvent whereas 18O from 18O2 cleavage is incorporated in the hydroxide bridge. In R2lox, the two water molecules from four-electron O2 reduction are released in a two-step reaction to the solvent. These results establish combined NRVS and QM/MM for tracking of iron-based oxygen activation in biological and chemical catalysts and clarify the reductive O2 cleavage route in an enzyme.
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Affiliation(s)
- Stefan Mebs
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16, 10691 Stockholm, Sweden
| | - Ramona Kositzki
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Julia J Griese
- Department of Cell and Molecular Biology, Structural Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16, 10691 Stockholm, Sweden
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
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43
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Theoretical Insights into the Aerobic Hydrogenase Activity of Molybdenum–Copper CO Dehydrogenase. INORGANICS 2019. [DOI: 10.3390/inorganics7110135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The Mo/Cu-dependent CO dehydrogenase from O. carboxydovorans is an enzyme that is able to catalyse CO oxidation to CO 2 ; moreover, it also expresses hydrogenase activity, as it is able to oxidize H 2 . Here, we have studied the dihydrogen oxidation catalysis by this enzyme using QM/MM calculations. Our results indicate that the equatorial oxo ligand of Mo is the best suited base for catalysis. Moreover, extraction of the first proton from H 2 by means of this basic centre leads to the formation of a Mo–OH–Cu I H hydride that allows for the stabilization of the copper hydride, otherwise known to be very unstable. In light of our results, two mechanisms for the hydrogenase activity of the enzyme are proposed. The first reactive channel depends on protonation of the sulphur atom of a Cu-bound cysteine residues, which appears to favour the binding and activation of the substrate. The second reactive channel involves a frustrated Lewis pair, formed by the equatorial oxo group bound to Mo and by the copper centre. In this case, no binding of the hydrogen molecule to the Cu center is observed but once H 2 enters into the active site, it can be split following a low-energy path.
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44
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Senger M, Eichmann V, Laun K, Duan J, Wittkamp F, Knör G, Apfel UP, Happe T, Winkler M, Heberle J, Stripp ST. How [FeFe]-Hydrogenase Facilitates Bidirectional Proton Transfer. J Am Chem Soc 2019; 141:17394-17403. [PMID: 31580662 PMCID: PMC6823627 DOI: 10.1021/jacs.9b09225] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Hydrogenases are metalloenzymes that
catalyze the conversion of
protons and molecular hydrogen, H2. [FeFe]-hydrogenases
show particularly high rates of hydrogen turnover and have inspired
numerous compounds for biomimetic H2 production. Two decades
of research on the active site cofactor of [FeFe]-hydrogenases have
put forward multiple models of the catalytic proceedings. In comparison,
our understanding of proton transfer is poor. Previously, residues
were identified forming a hydrogen-bonding network between active
site cofactor and bulk solvent; however, the exact mechanism of catalytic
proton transfer remained inconclusive. Here, we employ in
situ infrared difference spectroscopy on the [FeFe]-hydrogenase
from Chlamydomonas reinhardtii evaluating dynamic
changes in the hydrogen-bonding network upon photoreduction. While
proton transfer appears to be impaired in the oxidized state (Hox), the presented data support continuous proton transfer
in the reduced state (Hred). Our analysis allows for
a direct, molecular unique assignment to individual amino acid residues.
We found that transient protonation changes of glutamic acid residue
E141 and, most notably, arginine R148 facilitate bidirectional proton
transfer in [FeFe]-hydrogenases.
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Affiliation(s)
- Moritz Senger
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Viktor Eichmann
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Konstantin Laun
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | | | | | - Günther Knör
- Institute of Inorganic Chemistry , Johannes Kepler Universität Linz , Altenberger Straße 69 , 4040 Linz , Austria
| | | | | | | | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Sven Timo Stripp
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
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45
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Sanchez MLK, Sommer C, Reijerse E, Birrell JA, Lubitz W, Dyer RB. Investigating the Kinetic Competency of CrHydA1 [FeFe] Hydrogenase Intermediate States via Time-Resolved Infrared Spectroscopy. J Am Chem Soc 2019; 141:16064-16070. [DOI: 10.1021/jacs.9b08348] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Monica L. K. Sanchez
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Constanze Sommer
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Edward Reijerse
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - James A. Birrell
- 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
| | - R. Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
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46
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Duan J, Mebs S, Laun K, Wittkamp F, Heberle J, Happe T, Hofmann E, Apfel UP, Winkler M, Senger M, Haumann M, Stripp ST. Geometry of the Catalytic Active Site in [FeFe]-Hydrogenase Is Determined by Hydrogen Bonding and Proton Transfer. ACS Catal 2019. [DOI: 10.1021/acscatal.9b02203] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Stefan Mebs
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195 Berlin, Germany
| | - Konstantin Laun
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr University Bochum, 44801 Bochum, Germany
| | - Joachim Heberle
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Eckhard Hofmann
- Faculty of Biology and Biotechnology, Protein Crystallography, Ruhr University Bochum, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr University Bochum, 44801 Bochum, Germany
- Fraunhofer UMSICHT, 46047 Oberhausen, Germany
| | - Martin Winkler
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195 Berlin, Germany
| | - Sven T. Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
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47
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Wang Z, He J, Lü S, Jiang W, Wu Y, Jiang J, Xie Y, Mu C, Li A, Li Y, Li Q. Monophosphine‐substituted diiron azadithiolate complexes: New syntheses, characterization and electrochemical properties. Appl Organomet Chem 2019. [DOI: 10.1002/aoc.5184] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Zheng Wang
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Jiao He
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Shuang Lü
- College of Chemistry and Chemical EngineeringLiaocheng University Liaocheng 252000 China
| | - Wei‐Dong Jiang
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Yu Wu
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Jin Jiang
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Ying Xie
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Chao Mu
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Ao Li
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Yu‐Long Li
- College of Chemistry and Environmental EngineeringSichuan University of Science and Engineering Zigong 643000 China
| | - Qian‐Li Li
- College of Chemistry and Chemical EngineeringLiaocheng University Liaocheng 252000 China
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48
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Abstract
The active site (H-cluster) of [FeFe]-hydrogenases is a blueprint for the design of a biologically inspired H2-producing catalyst. The maturation process describes the preassembly and uptake of the unique [2FeH] cluster into apo-hydrogenase, which is to date not fully understood. In this study, we targeted individual amino acids by site-directed mutagenesis in the [FeFe]-hydrogenase CpI of Clostridium pasteurianum to reveal the final steps of H-cluster maturation occurring within apo-hydrogenase. We identified putative key positions for cofactor uptake and the subsequent structural reorganization that stabilizes the [2FeH] cofactor in its functional coordination sphere. Our results suggest that functional integration of the negatively charged [2FeH] precursor requires the positive charges and individual structural features of the 2 basic residues of arginine 449 and lysine 358, which mark the entrance and terminus of the maturation channel, respectively. The results obtained for 5 glycine-to-histidine exchange variants within a flexible loop region provide compelling evidence that the glycine residues function as hinge positions in the refolding process, which closes the secondary ligand sphere of the [2FeH] cofactor and the maturation channel. The conserved structural motifs investigated here shed light on the interplay between the secondary ligand sphere and catalytic cofactor.
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49
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Németh B, Esmieu C, Redman HJ, Berggren G. Monitoring H-cluster assembly using a semi-synthetic HydF protein. Dalton Trans 2019; 48:5978-5986. [PMID: 30632592 PMCID: PMC6509880 DOI: 10.1039/c8dt04294b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/21/2018] [Indexed: 11/21/2022]
Abstract
The [FeFe] hydrogenase enzyme interconverts protons and molecular hydrogen with remarkable efficiency. The reaction is catalysed by a unique metallo-cofactor denoted as the H-cluster containing an organometallic dinuclear Fe component, the [2Fe] subsite. The HydF protein delivers a precursor of the [2Fe] subsite to the apo-[FeFe] hydrogenase, thus completing the H-cluster and activating the enzyme. Herein we generate a semi-synthetic form of HydF by loading it with a synthetic low valent dinuclear Fe complex. We show that this semi-synthetic protein is practically indistinguishable from the native protein, and utilize this form of HydF to explore the mechanism of H-cluster assembly. More specifically, we show that transfer of the precatalyst from HydF to the hydrogenase enzyme results in the release of CO, underscoring that the pre-catalyst is a four CO species when bound to HydF. Moreover, we propose that an electron transfer reaction occurs during H-cluster assembly, resulting in an oxidation of the [2Fe] subsite with concomitant reduction of the [4Fe4S] cluster present on the HydF protein.
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Affiliation(s)
- Brigitta Németh
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
| | - Charlène Esmieu
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
| | - Holly J. Redman
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
| | - Gustav Berggren
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
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50
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Affiliation(s)
- Eric S. Wiedner
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999,
K2-57, Richland, Washington 99352, United States
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