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Lachmann MT, Duan Z, Rodríguez-Maciá P, Birrell JA. The missing pieces in the catalytic cycle of [FeFe] hydrogenases. Chem Sci 2024:d4sc04041d. [PMID: 39246377 PMCID: PMC11376134 DOI: 10.1039/d4sc04041d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Accepted: 08/02/2024] [Indexed: 09/10/2024] Open
Abstract
Hydrogen could provide a suitable means for storing energy from intermittent renewable sources for later use on demand. However, many challenges remain regarding the activity, specificity, stability and sustainability of current hydrogen production and consumption methods. The lack of efficient catalysts based on abundant and sustainable elements lies at the heart of this problem. Nature's solution led to the evolution of hydrogenase enzymes capable of reversible hydrogen conversion at high rates using iron- and nickel-based active sites. Through a detailed understanding of these enzymes, we can learn how to mimic them to engineer a new generation of highly active synthetic catalysts. Incredible progress has been made in our understanding of biological hydrogen activation over the last few years. In particular, detailed studies of the [FeFe] hydrogenase class have provided substantial insight into a sophisticated, optimised, molecular catalyst, the active site H-cluster. In this short perspective, we will summarise recent findings and highlight the missing pieces needed to complete the puzzle.
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Affiliation(s)
- Manon T Lachmann
- School of Chemistry and Leicester Institute of Structural and Chemical Biology, University of Leicester Leicester LE1 7RH UK
| | - Zehui Duan
- University of Oxford, Department of Chemistry, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Patricia Rodríguez-Maciá
- School of Chemistry and Leicester Institute of Structural and Chemical Biology, University of Leicester Leicester LE1 7RH UK
| | - James A Birrell
- School of Life Sciences, University of Essex Colchester CO4 3SQ UK
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2
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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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Understanding 2D-IR Spectra of Hydrogenases: A Descriptive and Predictive Computational Study. Catalysts 2022. [DOI: 10.3390/catal12090988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
[NiFe] hydrogenases are metalloenzymes that catalyze the reversible cleavage of dihydrogen (), a clean future fuel. Understanding the mechanism of these biocatalysts requires spectroscopic techniques that yield insights into the structure and dynamics of the [NiFe] active site. Due to the presence of CO and ligands at this cofactor, infrared (IR) spectroscopy represents an ideal technique for studying these aspects, but molecular information from linear IR absorption experiments is limited. More detailed insights can be obtained from ultrafast nonlinear IR techniques like IRpump−IRprobe and two-dimensional (2D-)IR spectroscopy. However, fully exploiting these advanced techniques requires an in-depth understanding of experimental observables and the encoded molecular information. To address this challenge, we present a descriptive and predictive computational approach for the simulation and analysis of static 2D-IR spectra of [NiFe] hydrogenases and similar organometallic systems. Accurate reproduction of experimental spectra from a first-coordination-sphere model suggests a decisive role of the [NiFe] core in shaping the enzymatic potential energy surface. We also reveal spectrally encoded molecular information that is not accessible by experiments, thereby helping to understand the catalytic role of the diatomic ligands, structural differences between [NiFe] intermediates, and possible energy transfer mechanisms. Our studies demonstrate the feasibility and benefits of computational spectroscopy in the 2D-IR investigation of hydrogenases, thereby further strengthening the potential of this nonlinear IR technique as a powerful research tool for the investigation of complex bioinorganic molecules.
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Fasano A, Land H, Fourmond V, Berggren G, Léger C. Reversible or Irreversible Catalysis of H +/H 2 Conversion by FeFe Hydrogenases. J Am Chem Soc 2021; 143:20320-20325. [PMID: 34813699 DOI: 10.1021/jacs.1c09554] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studies of molecular catalysts traditionally aim at understanding how a certain mechanism allows the reaction to be fast. A distinct question, which has only recently received attention in the case of bidirectional molecular catalysts, is how much thermodynamic driving force is required to achieve fast catalysis in either direction of the reaction. "Reversible" catalysts are bidirectional catalysts that work either way in response to even a small departure from equilibrium and thus do not waste input free energy as heat; conversely, "irreversible" catalysts require a large driving force to proceed at an appreciable rate [Fourmond et al. Nat. Rev. Chem. 2021, 5, 348-360]. Numerous mechanistic rationales for these contrasting behaviors have been proposed. To understand the determinants of catalytic (ir)reversibility, we examined the steady-state, direct electron transfer voltammetry of a particular FeFe hydrogenase, from Thermoanaerobacter mathranii, which is very unusual in that it irreversibly catalyzes H2 oxidation and production: a large overpotential is required for the reaction to proceed in either direction [Land et al. Chem. Sci. 2020, 11, 12789-12801]. In contrast to previous hypotheses, we demonstrate that in this particular enzyme catalytic irreversibility can be explained without invoking slow interfacial electron transfer or variations in the mechanism: the observed kinetics is fully consistent with the same catalytic pathway being used in both directions of the reaction.
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Affiliation(s)
- Andrea Fasano
- Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, Aix Marseille Université, 31 ch. Joseph Aiguier, 13009 Marseille, France
| | - Henrik Land
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, Box-523, Uppsala 751 20, Sweden
| | - Vincent Fourmond
- Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, Aix Marseille Université, 31 ch. Joseph Aiguier, 13009 Marseille, France
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry-Ångström, Uppsala University, Box-523, Uppsala 751 20, Sweden
| | - Christophe Léger
- Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, Aix Marseille Université, 31 ch. Joseph Aiguier, 13009 Marseille, France
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5
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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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6
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Affiliation(s)
- Brandon L. Greene
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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7
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Arizzi M, Morra S, Gilardi G, Pugliese M, Gullino ML, Valetti F. Improving sustainable hydrogen production from green waste: [FeFe]-hydrogenases quantitative gene expression RT-qPCR analysis in presence of autochthonous consortia. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:182. [PMID: 34530890 PMCID: PMC8444407 DOI: 10.1186/s13068-021-02028-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 08/28/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND Bio-hydrogen production via dark fermentation of low-value waste is a potent and simple mean of recovering energy, maximising the harvesting of reducing equivalents to produce the cleanest fuel amongst renewables. Following several position papers from companies and public bodies, the hydrogen economy is regaining interest, especially in combination with circular economy and the environmental benefits of short local supply chains, aiming at zero net emission of greenhouse gases (GHG). The biomasses attracting the largest interest are agricultural and urban green wastes (pruning of trees, collected leaves, grass clippings from public parks and boulevards), which are usually employed in compost production, with some concerns over the GHG emission during the process. Here, an alternative application of green wastes, low-value compost and intermediate products (partially composted but unsuitable for completing the process) is studied, pointing at the autochthonous microbial consortium as an already selected source of implementation for biomass degradation and hydrogen production. The biocatalysts investigated as mainly relevant for hydrogen production were the [FeFe]-hydrogenases expressed in Clostridia, given their very high turnover rates. RESULTS Bio-hydrogen accumulation was related to the modulation of gene expression of multiple [FeFe]-hydrogenases from two strains (Clostridium beijerinckii AM2 and Clostridium tyrobutyricum AM6) isolated from the same waste. Reverse Transcriptase quantitative PCR (RT-qPCR) was applied over a period of 288 h and the RT-qPCR results showed that C. beijerinckii AM2 prevailed over C. tyrobutyricum AM6 and a high expression modulation of the 6 different [FeFe]-hydrogenase genes of C. beijerinckii in the first 23 h was observed, sustaining cumulative hydrogen production of 0.6 to 1.2 ml H2/g VS (volatile solids). These results are promising in terms of hydrogen yields, given that no pre-treatment was applied, and suggested a complex cellular regulation, linking the performance of dark fermentation with key functional genes involved in bio-H2 production in presence of the autochthonous consortium, with different roles, time, and mode of expression of the involved hydrogenases. CONCLUSIONS An applicative outcome of the hydrogenases genes quantitative expression analysis can be foreseen in optimising (on the basis of the acquired functional data) hydrogen production from a nutrient-poor green waste and/or low added value compost, in a perspective of circular bioeconomy.
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Affiliation(s)
- M Arizzi
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, 10123, Torino, Italy
- Acea Engineering Laboratories Research Innovation SpA, Roma, Italy
| | - S Morra
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, 10123, Torino, Italy
- Faculty of Engineering, University of Nottingham, Nottingham, UK
| | - G Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, 10123, Torino, Italy
| | - M Pugliese
- Centre of Competence for Innovation in Agro-Environmental Field (Agroinnova) and DiSAFA, University of Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
- AgriNewTech Srl, Via Livorno 60, 10140, Torino, Italy
| | - M L Gullino
- Centre of Competence for Innovation in Agro-Environmental Field (Agroinnova) and DiSAFA, University of Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
- AgriNewTech Srl, Via Livorno 60, 10140, Torino, Italy
| | - F Valetti
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, 10123, Torino, Italy.
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Affiliation(s)
- Sven T. Stripp
- Freie Universität Berlin, Department of Physics, Arnimallee 14, 14195 Berlin, Germany
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9
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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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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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11
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Recent Advancements and Future Prospects in Ultrathin 2D Semiconductor-Based Photocatalysts for Water Splitting. Catalysts 2020. [DOI: 10.3390/catal10101111] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ultrathin two-dimensional (2D) semiconductor-mediated photocatalysts have shown their compelling potential and have arguably received tremendous attention in photocatalysis because of their superior thickness-dependent physical, chemical, mechanical and optical properties. Although numerous comprehensions about 2D semiconductor photocatalysts have been amassed up to now, low cost efficiency, degradation, kinetics of charge transfer along with recycling are still the big challenges to realize a wide application of 2D semiconductor-based photocatalysis. At present, most photocatalysts still need rare or expensive noble metals to improve the photocatalytic activity, which inhibits their commercial-scale application extremely. Thus, developing less costly, earth-abundant semiconductor-based photocatalysts with efficient conversion of sunlight energy remains the primary challenge. In this review, it begins with a brief description of the general mechanism of overall photocatalytic water splitting. Then a concise overview of different types of 2D semiconductor-mediated photocatalysts is given to figure out the advantages and disadvantages for mentioned semiconductor-based photocatalysis, including the structural property and stability, synthesize method, electrochemical property and optical properties for H2/O2 production half reaction along with overall water splitting. Finally, we conclude this review with a perspective, marked on some remaining challenges and new directions of 2D semiconductor-mediated photocatalysts.
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Holá K, Pavliuk MV, Németh B, Huang P, Zdražil L, Land H, Berggren G, Tian H. Carbon Dots and [FeFe] Hydrogenase Biohybrid Assemblies for Efficient Light-Driven Hydrogen Evolution. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02474] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Kateřina Holá
- Department of Chemistry—Ångström Laboratory, Physical Chemistry, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Mariia V. Pavliuk
- Department of Chemistry—Ångström Laboratory, Physical Chemistry, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
| | - Brigitta Németh
- Department of Chemistry—Ångström Laboratory, Molecular Biomimetic, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
| | - Ping Huang
- Department of Chemistry—Ångström Laboratory, Molecular Biomimetic, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
| | - Lukáš Zdražil
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Henrik Land
- Department of Chemistry—Ångström Laboratory, Molecular Biomimetic, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
| | - Gustav Berggren
- Department of Chemistry—Ångström Laboratory, Molecular Biomimetic, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
| | - Haining Tian
- Department of Chemistry—Ångström Laboratory, Physical Chemistry, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
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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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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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Chongdar N, Pawlak K, Rüdiger O, Reijerse EJ, Rodríguez-Maciá P, Lubitz W, Birrell JA, Ogata H. Spectroscopic and biochemical insight into an electron-bifurcating [FeFe] hydrogenase. J Biol Inorg Chem 2019; 25:135-149. [PMID: 31823008 PMCID: PMC7064455 DOI: 10.1007/s00775-019-01747-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 11/21/2019] [Indexed: 01/28/2023]
Abstract
Abstract The heterotrimeric electron-bifurcating [FeFe] hydrogenase (HydABC) from Thermotoga maritima (Tm) couples the endergonic reduction of protons (H+) by dihydronicotinamide adenine dinucleotide (NADH) (∆G0 ≈ 18 kJ mol−1) to the exergonic reduction of H+ by reduced ferredoxin (Fdred) (∆G0 ≈ − 16 kJ mol−1). The specific mechanism by which HydABC functions is not understood. In the current study, we describe the biochemical and spectroscopic characterization of TmHydABC recombinantly produced in Escherichia coli and artificially maturated with a synthetic diiron cofactor. We found that TmHydABC catalyzed the hydrogen (H2)-dependent reduction of nicotinamide adenine dinucleotide (NAD+) in the presence of oxidized ferredoxin (Fdox) at a rate of ≈17 μmol NADH min−1 mg−1. Our data suggest that only one flavin is present in the enzyme and is not likely to be the site of electron bifurcation. FTIR and EPR spectroscopy, as well as FTIR spectroelectrochemistry, demonstrated that the active site for H2 conversion, the H-cluster, in TmHydABC behaves essentially the same as in prototypical [FeFe] hydrogenases, and is most likely also not the site of electron bifurcation. The implications of these results are discussed with respect to the current hypotheses on the electron bifurcation mechanism of [FeFe] hydrogenases. Overall, the results provide insight into the electron-bifurcating mechanism and present a well-defined system for further investigations of this fascinating class of [FeFe] hydrogenases. Graphic abstract ![]()
Electronic supplementary material The online version of this article (10.1007/s00775-019-01747-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nipa Chongdar
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.
| | - Krzysztof Pawlak
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Olaf Rüdiger
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Edward J Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Patricia Rodríguez-Maciá
- 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.
| | - Hideaki Ogata
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany. .,Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo, 060-0819, Japan.
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Horch M, Schoknecht J, Wrathall SLD, Greetham GM, Lenz O, Hunt NT. Understanding the structure and dynamics of hydrogenases by ultrafast and two-dimensional infrared spectroscopy. Chem Sci 2019; 10:8981-8989. [PMID: 31762978 PMCID: PMC6857670 DOI: 10.1039/c9sc02851j] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 08/05/2019] [Indexed: 11/21/2022] Open
Abstract
Hydrogenases are valuable model enzymes for sustainable energy conversion approaches using H2, but rational utilization of these base-metal biocatalysts requires a detailed understanding of the structure and dynamics of their complex active sites. The intrinsic CO and CN- ligands of these metalloenzymes represent ideal chromophores for infrared (IR) spectroscopy, but structural and dynamic insight from conventional IR absorption experiments is limited. Here, we apply ultrafast and two-dimensional (2D) IR spectroscopic techniques, for the first time, to study hydrogenases in detail. Using an O2-tolerant [NiFe] hydrogenase as a model system, we demonstrate that IR pump-probe spectroscopy can explore catalytically relevant ligand bonding by accessing high-lying vibrational states. This ultrafast technique also shows that the protein matrix is influential in vibrational relaxation, which may be relevant for energy dissipation from the active site during fast reaction steps. Further insights into the relevance of the active site environment are provided by 2D-IR spectroscopy, which reveals equilibrium dynamics and structural constraints imposed on the H2-accepting intermediate of [NiFe] hydrogenases. Both techniques offer new strategies for uniquely identifying redox-structural states in complex catalytic mixtures via vibrational quantum beats and 2D-IR off-diagonal peaks. Together, these findings considerably expand the scope of IR spectroscopy in hydrogenase research, and new perspectives for the characterization of these enzymes and other (bio-)organometallic targets are presented.
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Affiliation(s)
- Marius Horch
- Department of Chemistry , York Biomedical Research Institute , University of York , Heslington , York , YO10 5DD , UK .
- Institut für Chemie , Technische Universität Berlin , Straße des 17. Juni 135 , Berlin , D-10623 , Germany
| | - Janna Schoknecht
- Institut für Chemie , Technische Universität Berlin , Straße des 17. Juni 135 , Berlin , D-10623 , Germany
| | - Solomon L D Wrathall
- Department of Chemistry , York Biomedical Research Institute , University of York , Heslington , York , YO10 5DD , UK .
| | - Gregory M Greetham
- STFC Central Laser Facility, Research Complex at Harwell , Rutherford Appleton Laboratory , Harwell Science and Innovation Campus , Didcot , Oxford , OX110PE , UK
| | - Oliver Lenz
- Institut für Chemie , Technische Universität Berlin , Straße des 17. Juni 135 , Berlin , D-10623 , Germany
| | - Neil T Hunt
- Department of Chemistry , York Biomedical Research Institute , University of York , Heslington , York , YO10 5DD , UK .
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17
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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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18
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Abstract
Over the past two decades, the bioinorganic chemistry of hydrogenases has attracted much interest from basic and applied research. Hydrogenases are highly efficient metalloenzymes that catalyze the reversible reduction of protons to molecular hydrogen (H2) in all domains of life. Their iron- and nickel-based cofactors represent promising blueprints for the design of biomimetic, synthetic catalysts. In this Account, we address the molecular proceedings of hydrogen turnover with [FeFe]-hydrogenases. The active site cofactor of [FeFe]-hydrogenases ("H-cluster") comprises a unique diiron complex linked to a [4Fe-4S] cluster via a single cysteine. Since it was discovered that a synthetic analogue of the diiron site can be incorporated into apoprotein in vitro to yield active enzyme, significant progress has been made toward a comprehensive understanding of hydrogenase catalysis. The diiron site carries three to four carbon monoxide (CO) and two cyanide (CN-) ligands that give rise to intense infrared (IR) absorption bands. These bands are sensitive reporters of the electron density across the H-cluster, which can be addressed by infrared spectroscopy to follow redox and protonation changes at the cofactor. Synthetic variation of the metal-bridging dithiolate ligand at the diiron site, as well as site-directed mutagenesis of amino acids, provides access to the proton pathways toward the cofactor. Quantum chemical calculations are employed to specifically assign IR bands to vibrational modes of the diatomic ligands and yield refined H-cluster geometries. Here, we provide an overview of recent research on [FeFe]-hydrogenases with emphasis on experimental and computational IR studies. We describe advances in attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR) and protein film electrochemistry, as well as density functional theory (DFT) calculations. Key cofactor species are discussed in terms of molecular geometry, redox state, and protonation. Isotope editing is introduced as a tool to evaluate the cofactor geometry beyond the limits of protein crystallography. In particular, the role of proton-coupled electron transfer (PCET) in the generation of catalytically relevant redox species is addressed. We propose that site-selective protonation of the H-cluster biases surplus electrons either to the [4Fe-4S] cluster or to the diiron site. Protonation of the [4Fe-4S] cluster prevents premature reduction at the diiron site and stabilizes a reactive, terminal hydride. The observed H-cluster species are assigned to rapid H2 conversion or to reactions possibly involved in activity regulation and cellular H2 sensing. In the catalytic cycle of [FeFe]-hydrogenases, an H-cluster geometry is preserved that features a bridging CO ligand. PCET levels the redox potential for two steps of sequential cofactor reduction. The concept of consecutive PCET at a geometrically inert cofactor with tight control of electron and proton localization may inspire the design of a novel generation of biomimetic catalysts for the production of H2 as a fuel.
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Affiliation(s)
- 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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19
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Esmieu C, Raleiras P, Berggren G. From protein engineering to artificial enzymes - biological and biomimetic approaches towards sustainable hydrogen production. SUSTAINABLE ENERGY & FUELS 2018; 2:724-750. [PMID: 31497651 PMCID: PMC6695573 DOI: 10.1039/c7se00582b] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/31/2018] [Indexed: 06/09/2023]
Abstract
Hydrogen gas is used extensively in industry today and is often put forward as a suitable energy carrier due its high energy density. Currently, the main source of molecular hydrogen is fossil fuels via steam reforming. Consequently, novel production methods are required to improve the sustainability of hydrogen gas for industrial processes, as well as paving the way for its implementation as a future solar fuel. Nature has already developed an elaborate hydrogen economy, where the production and consumption of hydrogen gas is catalysed by hydrogenase enzymes. In this review we summarize efforts on engineering and optimizing these enzymes for biological hydrogen gas production, with an emphasis on their inorganic cofactors. Moreover, we will describe how our understanding of these enzymes has been applied for the preparation of bio-inspired/-mimetic systems for efficient and sustainable hydrogen production.
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Affiliation(s)
- C Esmieu
- Department of Chemistry , Ångström Laboratory , Uppsala University , Box 523 , SE-75120 Uppsala , Sweden .
| | - P Raleiras
- Department of Chemistry , Ångström Laboratory , Uppsala University , Box 523 , SE-75120 Uppsala , Sweden .
| | - G Berggren
- Department of Chemistry , Ångström Laboratory , Uppsala University , Box 523 , SE-75120 Uppsala , Sweden .
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20
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Senger M, Mebs S, Duan J, Shulenina O, Laun K, Kertess L, Wittkamp F, Apfel UP, Happe T, Winkler M, Haumann M, Stripp ST. Protonation/reduction dynamics at the [4Fe-4S] cluster of the hydrogen-forming cofactor in [FeFe]-hydrogenases. Phys Chem Chem Phys 2018; 20:3128-3140. [PMID: 28884175 DOI: 10.1039/c7cp04757f] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The [FeFe]-hydrogenases of bacteria and algae are the most efficient hydrogen conversion catalysts in nature. Their active-site cofactor (H-cluster) comprises a [4Fe-4S] cluster linked to a unique diiron site that binds three carbon monoxide (CO) and two cyanide (CN-) ligands. Understanding microbial hydrogen conversion requires elucidation of the interplay of proton and electron transfer events at the H-cluster. We performed real-time spectroscopy on [FeFe]-hydrogenase protein films under controlled variation of atmospheric gas composition, sample pH, and reductant concentration. Attenuated total reflection Fourier-transform infrared spectroscopy was used to monitor shifts of the CO/CN- vibrational bands in response to redox and protonation changes. Three different [FeFe]-hydrogenases and several protein and cofactor variants were compared, including element and isotopic exchange studies. A protonated equivalent (HoxH) of the oxidized state (Hox) was found, which preferentially accumulated at acidic pH and under reducing conditions. We show that the one-electron reduced state Hred' represents an intrinsically protonated species. Interestingly, the formation of HoxH and Hred' was independent of the established proton pathway to the diiron site. Quantum chemical calculations of the respective CO/CN- infrared band patterns favored a cysteine ligand of the [4Fe-4S] cluster as the protonation site in HoxH and Hred'. We propose that proton-coupled electron transfer facilitates reduction of the [4Fe-4S] cluster and prevents premature formation of a hydride at the catalytic diiron site. Our findings imply that protonation events both at the [4Fe-4S] cluster and at the diiron site of the H-cluster are important in the hydrogen conversion reaction of [FeFe]-hydrogenases.
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Affiliation(s)
- Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
| | - Stefan Mebs
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Olga Shulenina
- Faculty of Physics, St. Petersburg State University, 198504 St. Petersburg, Russian Federation
| | - Konstantin Laun
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
| | - Leonie Kertess
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Martin Winkler
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
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21
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Chongdar N, Birrell JA, Pawlak K, Sommer C, Reijerse EJ, Rüdiger O, Lubitz W, Ogata H. Unique Spectroscopic Properties of the H-Cluster in a Putative Sensory [FeFe] Hydrogenase. J Am Chem Soc 2018; 140:1057-1068. [PMID: 29251926 DOI: 10.1021/jacs.7b11287] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sensory type [FeFe] hydrogenases are predicted to play a role in transcriptional regulation by detecting the H2 level of the cellular environment. These hydrogenases contain the hydrogenase domain with distinct modifications in the active site pocket, followed by a Per-Arnt-Sim (PAS) domain. As yet, neither the physiological function nor the biochemical or spectroscopic properties of these enzymes have been explored. Here, we present the characterization of an artificially maturated, putative sensory [FeFe] hydrogenase from Thermotoga maritima (HydS). This enzyme shows lower hydrogen conversion activity than prototypical [FeFe] hydrogenases and a reduced inhibition by CO. Using FTIR spectroelectrochemistry and EPR spectroscopy, three redox states of the active site were identified. The spectroscopic signatures of the most oxidized state closely resemble those of the Hox state from the prototypical [FeFe] hydrogenases, while the FTIR spectra of both singly and doubly reduced states show large differences. The FTIR bands of both the reduced states are strongly red-shifted relative to the Hox state, indicating reduction at the diiron site, but with retention of the bridging CO ligand. The unique functional and spectroscopic features of HydS are discussed with regard to the possible role of altered amino acid residues influencing the electronic properties of the H-cluster.
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Affiliation(s)
- Nipa Chongdar
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany
| | - James A Birrell
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany
| | - Krzysztof Pawlak
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany
| | - Constanze Sommer
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany
| | - Edward J Reijerse
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany
| | - Olaf Rüdiger
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany
| | - Hideaki Ogata
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany.,Institute of Low Temperature Science, Hokkaido University , Kita19 Nishi8, Kita-ku, 060-0819 Sapporo, Japan
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22
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Greene BL, Vansuch GE, Chica BC, Adams MWW, Dyer RB. Applications of Photogating and Time Resolved Spectroscopy to Mechanistic Studies of Hydrogenases. Acc Chem Res 2017; 50:2718-2726. [PMID: 29083854 DOI: 10.1021/acs.accounts.7b00356] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Rapid and facile redox chemistry is exemplified in nature by the oxidoreductases, the class of enzymes that catalyze electron transfer (ET) from a donor to an acceptor. The key role of oxidoreductases in metabolism and biosynthesis has imposed evolutionary pressure to enhance enzyme efficiency, pushing some toward the diffusion limit. Understanding the detailed molecular mechanisms of these highly optimized enzymes would provide an important foundation for the rational design of catalysts for multielectron chemistry, including fuel production. The hydrogenases (H2ases) are the oxidoreductases that catalyze the most basic electron and proton transfer reactions relevant to fuel production, the interconversion of protons and hydrogen, with kcat > 103 s-1. Thus, they provide a model system for studying the efficiency exhibited by oxidoreductases. Because of the extraordinarily fast catalytic rates of these enzymes, their mechanisms have been difficult to study directly but instead have been inferred from structural and steady-state measurements. Although informative, the kinetic competency of observed equilibrium steps can only be suggested by these methods, not demonstrated, because the fundamental (fast) catalytic steps remain unresolved, resulting in minimal insight regarding the underlying ET and proton transfer (PT) events. Motivated by this gap in understanding, we developed an approach capable of observing elementary ET and PT during such fast enzyme turnover by combining a laser-induced potential jump with time-resolved spectroscopy. The potential jump initiates enzyme turnover by utilizing a short-pulsed laser to release a "caged" electron from a nanomaterial or NAD(P)H, which is then captured by a mediator such as methyl viologen. The subsequent enzyme reduction and turnover are monitored by transient absorption spectroscopy in the visible or mid-IR spectral regions. The method is completely general and in principle can be applied to any catalytic redox reaction. In the case of hydrogenases, time-resolved infrared spectroscopy of the active site CO ligands is particularly informative since the IR frequencies are exquisitely sensitive to the redox and protonation states. Using this methodology, we have developed a description of the catalytic mechanism of the Pyrococcus furiosus [NiFe]-hydrogenase by demonstrating the kinetic and chemical competency of equilibrium states and by invoking new intermediates. Additionally, the pre-steady-state kinetics revealed a distinct role of proton tunneling in concerted electron-proton transfer (EPT) modulated by a conserved glutamic acid residue. Similar multisite EPT processes have been implicated in numerous enzymes but have not been demonstrated explicitly. These methods have also been successfully applied to an electron bifurcating [FeFe]-H2ase from Thermotoga maritima, establishing the kinetic competency of the Hox, Hred, and Hsred intermediates of the [FeFe] enzyme. These results provide fundamental insight on the factors that control low barrier proton and electron flow in enzymes and thus provide a foundation for the rational design of reversible biomimetic catalysts.
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Affiliation(s)
- Brandon L. Greene
- Department
of Chemistry, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Gregory E. Vansuch
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Bryant C. Chica
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Michael W. W. Adams
- Department
of Biochemistry and Molecular Biology, University of Georgia, B122 Life
Sciences Bldg., Athens, Georgia 30602, United States
| | - R. Brian Dyer
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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23
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Möller F, Piontek S, Miller RG, Apfel UP. From Enzymes to Functional Materials-Towards Activation of Small Molecules. Chemistry 2017; 24:1471-1493. [PMID: 28816379 DOI: 10.1002/chem.201703451] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 08/15/2017] [Indexed: 12/12/2022]
Abstract
The design of non-noble metal-containing heterogeneous catalysts for the activation of small molecules is of utmost importance for our society. While nature possesses very sophisticated machineries to perform such conversions, rationally designed catalytic materials are rare. Herein, we aim to raise the awareness of the overall common design and working principles of catalysts incorporating aspects of biology, chemistry, and material sciences.
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Affiliation(s)
- Frauke Möller
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
| | - Stefan Piontek
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
| | - Reece G Miller
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
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24
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Ratzloff MW, Wilker MB, Mulder DW, Lubner CE, Hamby H, Brown KA, Dukovic G, King PW. Activation Thermodynamics and H/D Kinetic Isotope Effect of the Hox to HredH+ Transition in [FeFe] Hydrogenase. J Am Chem Soc 2017; 139:12879-12882. [DOI: 10.1021/jacs.7b04216] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Michael W. Ratzloff
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Molly B. Wilker
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - David W. Mulder
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Carolyn E. Lubner
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Hayden Hamby
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Katherine A. Brown
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Gordana Dukovic
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Paul W. King
- Biosciences
Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
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25
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Reversible isomerization of a novel [FeFe]‑hydrogenase model complex and water-promoted electrocatalytic proton reduction. Electrochem commun 2017. [DOI: 10.1016/j.elecom.2017.07.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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