1
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Trevino RE, Fuller JT, Reid DJ, Laureanti JA, Ginovska B, Linehan JC, Shaw WJ. Understanding the role of negative charge in the scaffold of an artificial enzyme for CO 2 hydrogenation on catalysis. J Biol Inorg Chem 2024:10.1007/s00775-024-02070-0. [PMID: 39207604 DOI: 10.1007/s00775-024-02070-0] [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: 04/26/2024] [Accepted: 07/22/2024] [Indexed: 09/04/2024]
Abstract
We have approached the construction of an artificial enzyme by employing a robust protein scaffold, lactococcal multidrug resistance regulator, LmrR, providing a structured secondary and outer coordination spheres around a molecular rhodium complex, [RhI(PEt2NglyPEt2)2]-. Previously, we demonstrated a 2-3 fold increase in activity for one Rh-LmrR construct by introducing positive charge in the secondary coordination sphere. In this study, a series of variants was made through site-directed mutagenesis where the negative charge is located in the secondary sphere or outer coordination sphere, with additional variants made with increasingly negative charge in the outer coordination sphere while keeping a positive charge in the secondary sphere. Placing a negative charge in the secondary or outer coordination sphere demonstrates decreased activity by a factor of two compared to the wild-type Rh-LmrR. Interestingly, addition of positive charge in the secondary sphere, with the negatively charged outer coordination sphere restores activity. Vibrational and NMR spectroscopy suggest minimal changes to the electronic density at the rhodium center, regardless of inclusion of a negative or positive charge in the secondary sphere, suggesting another mechanism is impacting catalytic activity, explored in the discussion.
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Affiliation(s)
- Regina E Trevino
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, MSIN J7-10, PO Box 999, Richland, WA, 99352, USA
| | - Jack T Fuller
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, MSIN J7-10, PO Box 999, Richland, WA, 99352, USA
| | - Deseree J Reid
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, MSIN J7-10, PO Box 999, Richland, WA, 99352, USA
| | - Joseph A Laureanti
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, MSIN J7-10, PO Box 999, Richland, WA, 99352, USA
- Admiral Instruments, Tempe, AZ, 85281, USA
| | - Bojana Ginovska
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, MSIN J7-10, PO Box 999, Richland, WA, 99352, USA
| | - John C Linehan
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, MSIN J7-10, PO Box 999, Richland, WA, 99352, USA
| | - Wendy J Shaw
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, MSIN J7-10, PO Box 999, Richland, WA, 99352, USA.
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2
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Davis V, Frielingsdorf S, Hu Q, Elsäßer P, Balzer BN, Lenz O, Zebger I, Fischer A. Ultrathin Film Antimony-Doped Tin Oxide Prevents [NiFe] Hydrogenase Inactivation at High Electrode Potentials. ACS APPLIED MATERIALS & INTERFACES 2024; 16:44802-44816. [PMID: 39160667 DOI: 10.1021/acsami.4c08218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
For hydrogenases to serve as effective electrocatalysts in hydrogen biotechnological devices, such as enzymatic fuel cells, it is imperative to design electrodes that facilitate stable and functional enzyme immobilization, efficient substrate accessibility, and effective interfacial electron transfer. Recent years have seen considerable advancements in this area, particularly concerning hydrogenases. However, a significant limitation remains: the inactivation of hydrogenases at high oxidative potentials across most developed electrodes. Addressing this issue necessitates a thorough understanding of the interactions between the enzyme and the electrode surface. In this study, we employ ATR-IR spectroscopy combined with electrochemistry in situ to investigate the interaction mechanisms, electrocatalytic behavior, and stability of the oxygen-tolerant membrane-bound [NiFe] hydrogenase from Cupriavidus necator (MBH), which features a His-tag on its small subunit C-terminus. Antimony-doped tin oxide (ATO) thin films were selected as electrodes due to their protein compatibility, suitable potential window, conductivity, and transparency, making them an ideal platform for spectroelectrochemical measurements. Our comprehensive examination of the physiological and electrochemical processes of [NiFe] MBH on ATO thin film electrodes demonstrates that by tuning the electron transport properties of the ATO thin film, we can prevent MBH inactivation at extended oxidative potentials while maintaining direct electron transfer between the enzyme and the electrode.
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Affiliation(s)
- Victoria Davis
- Institute of Inorganic and Analytical Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
- Freiburger Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Str. 21, 79104 Freiburg, Germany
| | - Stefan Frielingsdorf
- Institute of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135 & 124, 10623 Berlin, Germany
| | - Qiwei Hu
- Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
- Institute of Physical Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Patrick Elsäßer
- Institute of Inorganic and Analytical Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
| | - Bizan N Balzer
- Freiburger Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Str. 21, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
- Institute of Physical Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Oliver Lenz
- Institute of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135 & 124, 10623 Berlin, Germany
| | - Ingo Zebger
- Institute of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135 & 124, 10623 Berlin, Germany
| | - Anna Fischer
- Institute of Inorganic and Analytical Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
- Freiburger Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Str. 21, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
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3
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Sirohiwal A, Gamiz-Hernandez AP, Kaila VRI. Mechanistic Principles of Hydrogen Evolution in the Membrane-Bound Hydrogenase. J Am Chem Soc 2024; 146:18019-18031. [PMID: 38888987 PMCID: PMC11228991 DOI: 10.1021/jacs.4c04476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/20/2024]
Abstract
The membrane-bound hydrogenase (Mbh) from Pyrococcus furiosus is an archaeal member of the Complex I superfamily. It catalyzes the reduction of protons to H2 gas powered by a [NiFe] active site and transduces the free energy into proton pumping and Na+/H+ exchange across the membrane. Despite recent structural advances, the mechanistic principles of H2 catalysis and ion transport in Mbh remain elusive. Here, we probe how the redox chemistry drives the reduction of the proton to H2 and how the catalysis couples to conformational dynamics in the membrane domain of Mbh. By combining large-scale quantum chemical density functional theory (DFT) and correlated ab initio wave function methods with atomistic molecular dynamics simulations, we show that the proton transfer reactions required for the catalysis are gated by electric field effects that direct the protons by water-mediated reactions from Glu21L toward the [NiFe] site, or alternatively along the nearby His75L pathway that also becomes energetically feasible in certain reaction steps. These local proton-coupled electron transfer (PCET) reactions induce conformational changes around the active site that provide a key coupling element via conserved loop structures to the ion transport activity. We find that H2 forms in a heterolytic proton reduction step, with spin crossovers tuning the energetics along key reaction steps. On a general level, our work showcases the role of electric fields in enzyme catalysis and how these effects are employed by the [NiFe] active site of Mbh to drive PCET reactions and ion transport.
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Affiliation(s)
- Abhishek Sirohiwal
- Department of Biochemistry
and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - 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
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4
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Yang Z, Shi S, He X, Cao M, Lin H, Fu J, Zhou J. High-efficient nutrient removal in a single-stage electrolysis-integrated sequencing batch biofilm reactor (E-SBBR) for low C/N sanitary sewage treatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119848. [PMID: 38113787 DOI: 10.1016/j.jenvman.2023.119848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/20/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
To efficiently remove nutrients from low C/N sanitary sewage by conventional biological process is challenging due to the lack of sufficient electron donors. A novel electrolysis-integrated sequencing batch biofilm reactor (E-SBBR) was established to promote nitrogen and phosphorus removal for sanitary sewage with low C/N ratios (3.5-1.5). Highly efficient removal of nitrogen (>79%) and phosphorus (>97%) was achieved in the E-SBBR operating under alternating anoxic/electrolysis-anoxic/aerobic conditions. The coexistence of autotrophic nitrifiers, electron transfer-related bacteria, and heterotrophic and autohydrogenotrophic denitrifiers indicated synergistic nitrogen removal via multiple nitrogen-removing pathways. Electrolysis application induced microbial anoxic ammonia oxidation, autohydrogenotrophic denitrification and electrocoagulation processes. Deinococcus enriched on the electrodes were likely to mediate the electricity-driven ammonia oxidation which promoted ammonia removal. PICRUSt2 indicated that the relative abundances of key genes (hyaA and hyaB) associated with hydrogen oxidation significantly increased with the decreasing C/N ratios. The high autohydrogenotrophic denitrification rates during the electrolysis-anoxic period could compensate for the decreased heterotrophic rates resulting from insufficient carbon sources and nitrate removal was dramatically enhanced. Electrocoagulation with iron anode was responsible for phosphorus removal. This study provides insights into mechanisms by which electrochemically assisted biological systems enhance nutrient removal for low C/N sanitary sewage.
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Affiliation(s)
- Zhi Yang
- College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, China
| | - Shuohui Shi
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Xuejie He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Meng Cao
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Hong Lin
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Jiahao Fu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Jian Zhou
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China.
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5
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T Waffo AF, Lorent C, Katz S, Schoknecht J, Lenz O, Zebger I, Caserta G. Structural Determinants of the Catalytic Ni a-L Intermediate of [NiFe]-Hydrogenase. J Am Chem Soc 2023. [PMID: 37328284 DOI: 10.1021/jacs.3c01625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
[NiFe]-hydrogenases catalyze the reversible cleavage of H2 into two protons and two electrons at the inorganic heterobimetallic NiFe center of the enzyme. Their catalytic cycle involves at least four intermediates, some of which are still under debate. While the core reaction, including H2/H- binding, takes place at the inorganic cofactor, a major challenge lies in identifying those amino acid residues that contribute to the reactivity and how they stabilize (short-lived) intermediate states. Using cryogenic infrared and electron paramagnetic resonance spectroscopy on the regulatory [NiFe]-hydrogenase from Cupriavidus necator, a model enzyme for the analysis of catalytic intermediates, we deciphered the structural basis of the hitherto elusive Nia-L intermediates. We unveiled the protonation states of a proton-accepting glutamate and a Ni-bound cysteine residue in the Nia-L1, Nia-L2, and the hydride-binding Nia-C intermediates as well as previously unknown conformational changes of amino acid residues in proximity of the bimetallic active site. As such, this study unravels the complexity of the Nia-L intermediate and reveals the importance of the protein scaffold in fine-tuning proton and electron dynamics in [NiFe]-hydrogenase.
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Affiliation(s)
- Armel F T Waffo
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - 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
| | - Janna Schoknecht
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Oliver Lenz
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Ingo Zebger
- 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
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6
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Opel F, Itzenhäuser MA, Wehner I, Lupacchini S, Lauterbach L, Lenz O, Klähn S. Toward a synthetic hydrogen sensor in cyanobacteria: Functional production of an oxygen-tolerant regulatory hydrogenase in Synechocystis sp. PCC 6803. Front Microbiol 2023; 14:1122078. [PMID: 37032909 PMCID: PMC10073562 DOI: 10.3389/fmicb.2023.1122078] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/22/2023] [Indexed: 04/11/2023] Open
Abstract
Cyanobacteria have raised great interest in biotechnology, e.g., for the sustainable production of molecular hydrogen (H2) using electrons from water oxidation. However, this is hampered by various constraints. For example, H2-producing enzymes compete with primary metabolism for electrons and are usually inhibited by molecular oxygen (O2). In addition, there are a number of other constraints, some of which are unknown, requiring unbiased screening and systematic engineering approaches to improve the H2 yield. Here, we introduced the regulatory [NiFe]-hydrogenase (RH) of Cupriavidus necator (formerly Ralstonia eutropha) H16 into the cyanobacterial model strain Synechocystis sp. PCC 6803. In its natural host, the RH serves as a molecular H2 sensor initiating a signal cascade to express hydrogenase-related genes when no additional energy source other than H2 is available. Unlike most hydrogenases, the C. necator enzymes are O2-tolerant, allowing their efficient utilization in an oxygenic phototroph. Similar to C. necator, the RH produced in Synechocystis showed distinct H2 oxidation activity, confirming that it can be properly matured and assembled under photoautotrophic, i.e., oxygen-evolving conditions. Although the functional H2-sensing cascade has not yet been established in Synechocystis yet, we utilized the associated two-component system consisting of a histidine kinase and a response regulator to drive and modulate the expression of a superfolder gfp gene in Escherichia coli. This demonstrates that all components of the H2-dependent signal cascade can be functionally implemented in heterologous hosts. Thus, this work provides the basis for the development of an intrinsic H2 biosensor within a cyanobacterial cell that could be used to probe the effects of random mutagenesis and systematically identify promising genetic configurations to enable continuous and high-yield production of H2 via oxygenic photosynthesis.
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Affiliation(s)
- Franz Opel
- Department of Solar Materials, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | | | - Isabel Wehner
- Department of Solar Materials, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Sara Lupacchini
- Department of Solar Materials, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Lars Lauterbach
- Institute of Applied Microbiology (iAMB), RWTH Aachen University, Aachen, Germany
| | - Oliver Lenz
- Institute of Chemistry, Technical University of Berlin, Berlin, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
- *Correspondence: Stephan Klähn,
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7
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Fan Q, Waldburger S, Neubauer P, Riedel SL, Gimpel M. Implementation of a high cell density fed-batch for heterologous production of active [NiFe]-hydrogenase in Escherichia coli bioreactor cultivations. Microb Cell Fact 2022; 21:193. [PMID: 36123684 PMCID: PMC9484157 DOI: 10.1186/s12934-022-01919-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/07/2022] [Indexed: 11/13/2022] Open
Abstract
Background O2-tolerant [NiFe]-hydrogenases offer tremendous potential for applications in H2-based technology. As these metalloenzymes undergo a complicated maturation process that requires a dedicated set of multiple accessory proteins, their heterologous production is challenging, thus hindering their fundamental understanding and the development of related applications. Taking these challenges into account, we selected the comparably simple regulatory [NiFe]-hydrogenase (RH) from Cupriavidus necator as a model for the development of bioprocesses for heterologous [NiFe]-hydrogenase production. We already reported recently on the high-yield production of catalytically active RH in Escherichia coli by optimizing the culture conditions in shake flasks. Results In this study, we further increase the RH yield and ensure consistent product quality by a rationally designed high cell density fed-batch cultivation process. Overall, the bioreactor cultivations resulted in ˃130 mg L−1 of catalytically active RH which is a more than 100-fold increase compared to other RH laboratory bioreactor scale processes with C. necator. Furthermore, the process shows high reproducibility of the previously selected optimized conditions and high productivity. Conclusions This work provides a good opportunity to readily supply such difficult-to-express complex metalloproteins economically and at high concentrations to meet the demand in basic and applied studies. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01919-w.
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Affiliation(s)
- Qin Fan
- Chair of Bioprocess Engineering, Technische Universität Berlin, Ackerstr. 76, ACK24, D-13355, Berlin, Germany
| | - Saskia Waldburger
- Chair of Bioprocess Engineering, Technische Universität Berlin, Ackerstr. 76, ACK24, D-13355, Berlin, Germany
| | - Peter Neubauer
- Chair of Bioprocess Engineering, Technische Universität Berlin, Ackerstr. 76, ACK24, D-13355, Berlin, Germany
| | - Sebastian L Riedel
- Chair of Bioprocess Engineering, Technische Universität Berlin, Ackerstr. 76, ACK24, D-13355, Berlin, Germany
| | - Matthias Gimpel
- Chair of Bioprocess Engineering, Technische Universität Berlin, Ackerstr. 76, ACK24, D-13355, Berlin, Germany.
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8
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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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9
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Fan Q, Caserta G, Lorent C, Zebger I, Neubauer P, Lenz O, Gimpel M. High-Yield Production of Catalytically Active Regulatory [NiFe]-Hydrogenase From Cupriavidus necator in Escherichia coli. Front Microbiol 2022; 13:894375. [PMID: 35572669 PMCID: PMC9100943 DOI: 10.3389/fmicb.2022.894375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/08/2022] [Indexed: 11/13/2022] Open
Abstract
Hydrogenases are biotechnologically relevant metalloenzymes that catalyze the reversible conversion of molecular hydrogen into protons and electrons. The O2-tolerant [NiFe]-hydrogenases from Cupriavidus necator (formerly Ralstonia eutropha) are of particular interest as they maintain catalysis even in the presence of molecular oxygen. However, to meet the demands of biotechnological applications and scientific research, a heterologous production strategy is required to overcome the low production yields in their native host. We have previously used the regulatory hydrogenase (RH) from C. necator as a model for the development of such a heterologous hydrogenase production process in E. coli. Although high protein yields were obtained, the purified enzyme was inactive due to the lack of the catalytic center, which contains an inorganic nickel-iron cofactor. In the present study, we significantly improved the production process to obtain catalytically active RH. We optimized important factors such as O2 content, metal availability, production temperature and time as well as the co-expression of RH-specific maturase genes. The RH was successfully matured during aerobic cultivation of E. coli by co-production of seven hydrogenase-specific maturases and a nickel permease, which was confirmed by activity measurements and spectroscopic investigations of the purified enzyme. The improved production conditions resulted in a high yield of about 80 mg L–1 of catalytically active RH and an up to 160-fold space-time yield in E. coli compared to that in the native host C. necator [<0.1 U (L d) –1]. Our strategy has important implications for the use of E. coli K-12 and B strains in the recombinant production of complex metalloenzymes, and provides a blueprint for the production of catalytically active [NiFe]-hydrogenases in biotechnologically relevant quantities.
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Affiliation(s)
- Qin Fan
- Chair of Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Giorgio Caserta
- Department of Chemistry, Technische Universität Berlin, Berlin, Germany
| | - Christian Lorent
- Department of Chemistry, Technische Universität Berlin, Berlin, Germany
| | - Ingo Zebger
- Department of Chemistry, Technische Universität Berlin, Berlin, Germany
| | - Peter Neubauer
- Chair of Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Oliver Lenz
- Department of Chemistry, Technische Universität Berlin, Berlin, Germany
| | - Matthias Gimpel
- Chair of Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Berlin, Germany
- *Correspondence: Matthias Gimpel,
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10
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Ash PA, Kendall-Price SET, Evans RM, Carr SB, Brasnett AR, Morra S, Rowbotham JS, Hidalgo R, Healy AJ, Cinque G, Frogley MD, Armstrong FA, Vincent KA. The crystalline state as a dynamic system: IR microspectroscopy under electrochemical control for a [NiFe] hydrogenase. Chem Sci 2021; 12:12959-12970. [PMID: 34745526 PMCID: PMC8514002 DOI: 10.1039/d1sc01734a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/03/2021] [Indexed: 12/24/2022] Open
Abstract
Controlled formation of catalytically-relevant states within crystals of complex metalloenzymes represents a significant challenge to structure-function studies. Here we show how electrochemical control over single crystals of [NiFe] hydrogenase 1 (Hyd1) from Escherichia coli makes it possible to navigate through the full array of active site states previously observed in solution. Electrochemical control is combined with synchrotron infrared microspectroscopy, which enables us to measure high signal-to-noise IR spectra in situ from a small area of crystal. The output reports on active site speciation via the vibrational stretching band positions of the endogenous CO and CN- ligands at the hydrogenase active site. Variation of pH further demonstrates how equilibria between catalytically-relevant protonation states can be deliberately perturbed in the crystals, generating a map of electrochemical potential and pH conditions which lead to enrichment of specific states. Comparison of in crystallo redox titrations with measurements in solution or of electrode-immobilised Hyd1 confirms the integrity of the proton transfer and redox environment around the active site of the enzyme in crystals. Slowed proton-transfer equilibria in the hydrogenase in crystallo reveals transitions which are only usually observable by ultrafast methods in solution. This study therefore demonstrates the possibilities of electrochemical control over single metalloenzyme crystals in stabilising specific states for further study, and extends mechanistic understanding of proton transfer during the [NiFe] hydrogenase catalytic cycle.
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Affiliation(s)
- Philip A Ash
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
- School of Chemistry, University of Leicester Leicester LE1 7RH UK
- Leicester Institute of Structural and Chemical Biology, University of Leicester LE1 7RH UK
| | - Sophie E T Kendall-Price
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Rhiannon M Evans
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Stephen B Carr
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus Didcot UK
| | - Amelia R Brasnett
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Simone Morra
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Jack S Rowbotham
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Ricardo Hidalgo
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Adam J Healy
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Gianfelice Cinque
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0QX UK
- Department of Engineering Sciences, University of Oxford Parks Road Oxford OX1 3PJ UK
| | - Mark D Frogley
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0QX UK
| | - Fraser A Armstrong
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR UK
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11
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Affiliation(s)
- Sven T. Stripp
- Freie Universität Berlin, Department of Physics, Arnimallee 14, 14195 Berlin, Germany
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12
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Fan Q, Caserta G, Lorent C, Lenz O, Neubauer P, Gimpel M. Optimization of Culture Conditions for Oxygen-Tolerant Regulatory [NiFe]-Hydrogenase Production from Ralstonia eutropha H16 in Escherichia coli. Microorganisms 2021; 9:1195. [PMID: 34073092 PMCID: PMC8229454 DOI: 10.3390/microorganisms9061195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 11/16/2022] Open
Abstract
Hydrogenases are abundant metalloenzymes that catalyze the reversible conversion of molecular H2 into protons and electrons. Important achievements have been made over the past two decades in the understanding of these highly complex enzymes. However, most hydrogenases have low production yields requiring many efforts and high costs for cultivation limiting their investigation. Heterologous production of these hydrogenases in a robust and genetically tractable expression host is an attractive strategy to make these enzymes more accessible. In the present study, we chose the oxygen-tolerant H2-sensing regulatory [NiFe]-hydrogenase (RH) from Ralstonia eutropha H16 owing to its relatively simple architecture compared to other [NiFe]-hydrogenases as a model to develop a heterologous hydrogenase production system in Escherichia coli. Using screening experiments in 24 deep-well plates with 3 mL working volume, we investigated relevant cultivation parameters, including inducer concentration, expression temperature, and expression time. The RH yield could be increased from 14 mg/L up to >250 mg/L by switching from a batch to an EnPresso B-based fed-batch like cultivation in shake flasks. This yield exceeds the amount of RH purified from the homologous host R. eutropha by several 100-fold. Additionally, we report the successful overproduction of the RH single subunits HoxB and HoxC, suitable for biochemical and spectroscopic investigations. Even though both RH and HoxC proteins were isolated in an inactive, cofactor free apo-form, the proposed strategy may powerfully accelerate bioprocess development and structural studies for both basic research and applied studies. These results are discussed in the context of the regulation mechanisms governing the assembly of large and small hydrogenase subunits.
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Affiliation(s)
- Qin Fan
- Institute of Biotechnology, Technische Universität Berlin, Chair of Bioprocess Engineering, Ackerstraße 76, D-13355 Berlin, Germany; (Q.F.); (P.N.)
| | - Giorgio Caserta
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany; (G.C.); (C.L.); (O.L.)
| | - Christian Lorent
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany; (G.C.); (C.L.); (O.L.)
| | - Oliver Lenz
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany; (G.C.); (C.L.); (O.L.)
| | - Peter Neubauer
- Institute of Biotechnology, Technische Universität Berlin, Chair of Bioprocess Engineering, Ackerstraße 76, D-13355 Berlin, Germany; (Q.F.); (P.N.)
| | - Matthias Gimpel
- Institute of Biotechnology, Technische Universität Berlin, Chair of Bioprocess Engineering, Ackerstraße 76, D-13355 Berlin, Germany; (Q.F.); (P.N.)
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13
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Murgida DH. In Situ Spectroelectrochemical Investigations of Electrode-Confined Electron-Transferring Proteins and Redox Enzymes. ACS OMEGA 2021; 6:3435-3446. [PMID: 33585730 PMCID: PMC7876673 DOI: 10.1021/acsomega.0c05746] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/19/2021] [Indexed: 06/09/2023]
Abstract
This perspective analyzes recent advances in the spectroelectrochemical investigation of redox proteins and enzymes immobilized on biocompatible or biomimetic electrode surfaces. Specifically, the article highlights new insights obtained by surface-enhanced resonance Raman (SERR), surface-enhanced infrared absorption (SEIRA), protein film infrared electrochemistry (PFIRE), polarization modulation infrared reflection-absorption spectroscopy (PMIRRAS), Förster resonance energy transfer (FRET), X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and differential electrochemical mass spectrometry (DMES)-based spectroelectrochemical methods on the structure, orientation, dynamics, and reaction mechanisms for a variety of immobilized species. This includes small heme and copper electron shuttling proteins, large respiratory complexes, hydrogenases, multicopper oxidases, alcohol dehydrogenases, endonucleases, NO-reductases, and dye decolorizing peroxidases, among other enzymes. Finally, I discuss the challenges and foreseeable future developments toward a better understanding of the functioning of these complex macromolecules and their exploitation in technological devices.
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Affiliation(s)
- Daniel H. Murgida
- Departamento
de Química Inorgánica, Analítica y Química-Física,
Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos
Aires 1428, Argentina
- Instituto
de Química Física de los Materiales, Medio Ambiente
y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina
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14
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Caserta G, Lorent C, Pelmenschikov V, Schoknecht J, Yoda Y, Hildebrandt P, Cramer SP, Zebger I, Lenz O. In Vitro Assembly as a Tool to Investigate Catalytic Intermediates of [NiFe]-Hydrogenase. ACS Catal 2020; 10:13890-13894. [PMID: 33680535 PMCID: PMC7932190 DOI: 10.1021/acscatal.0c04079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[NiFe]-hydrogenases catalyze the reversible reaction H2 ⇄ 2H+ + 2e-. Their basic module consists of a large subunit, coordinating the NiFe(CO)(CN)2 center, and a small subunit that carries electron-transferring iron-sulfur clusters. Here, we report the in vitro assembly of fully functional [NiFe]-hydrogenase starting from the isolated large and small subunits. Activity assays complemented by spectroscopic measurements revealed a native-like hydrogenase. This approach was used to label exclusively the NiFe(CO)(CN)2 center with 57Fe, enabling a clear view of the catalytic site by means of nuclear resonance vibrational spectroscopy. This strategy paves the way for in-depth studies of [NiFe]-hydrogenase catalytic intermediates.
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Affiliation(s)
- Giorgio Caserta
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Christian Lorent
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Vladimir Pelmenschikov
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Janna Schoknecht
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Yoshitaka Yoda
- Japan Synchrotron Radiation Research Institute, RIKEN SPring-8, Hyogo 679-5198, Japan
| | - Peter Hildebrandt
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Stephen P. Cramer
- SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043, United States
| | - Ingo Zebger
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Oliver Lenz
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
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15
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Chen H, Simoska O, Lim K, Grattieri M, Yuan M, Dong F, Lee YS, Beaver K, Weliwatte S, Gaffney EM, Minteer SD. Fundamentals, Applications, and Future Directions of Bioelectrocatalysis. Chem Rev 2020; 120:12903-12993. [DOI: 10.1021/acs.chemrev.0c00472] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Hui Chen
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Olja Simoska
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Koun Lim
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Matteo Grattieri
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Mengwei Yuan
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Fangyuan Dong
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Yoo Seok Lee
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Kevin Beaver
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Samali Weliwatte
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Erin M. Gaffney
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Shelley D. Minteer
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
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16
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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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17
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Caserta G, Lorent C, Ciaccafava A, Keck M, Breglia R, Greco C, Limberg C, Hildebrandt P, Cramer SP, Zebger I, Lenz O. The large subunit of the regulatory [NiFe]-hydrogenase from Ralstonia eutropha - a minimal hydrogenase? Chem Sci 2020; 11:5453-5465. [PMID: 34094072 PMCID: PMC8159394 DOI: 10.1039/d0sc01369b] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Chemically synthesized compounds that are capable of facilitating the reversible splitting of dihydrogen into protons and electrons are rare in chemists' portfolio. The corresponding biocatalysts – hydrogenases – are, however, abundant in the microbial world. [NiFe]-hydrogenases represent a major subclass and display a bipartite architecture, composed of a large subunit, hosting the catalytic NiFe(CO)(CN)2 cofactor, and a small subunit whose iron–sulfur clusters are responsible for electron transfer. To analyze in detail the catalytic competence of the large subunit without its smaller counterpart, we purified the large subunit HoxC of the regulatory [NiFe]-hydrogenase of the model H2 oxidizer Ralstonia eutropha to homogeneity. Metal determination and infrared spectroscopy revealed a stoichiometric loading of the metal cofactor. This enabled for the first time the determination of the UV-visible extinction coefficient of the NiFe(CO)(CN)2 cofactor. Moreover, the absence of disturbing iron–sulfur clusters allowed an unbiased look into the low-spin Fe2+ of the active site by Mössbauer spectroscopy. Isolated HoxC was active in catalytic hydrogen–deuterium exchange, demonstrating its capacity to activate H2. Its catalytic activity was drastically lower than that of the bipartite holoenzyme. This was consistent with infrared and electron paramagnetic resonance spectroscopic observations, suggesting that the bridging position between the active site nickel and iron ions is predominantly occupied by water-derived ligands, even under reducing conditions. In fact, the presence of water-derived ligands bound to low-spin Ni2+ was reflected by the absorption bands occurring in the corresponding UV-vis spectra, as revealed by time-dependent density functional theory calculations conducted on appropriate in silico models. Thus, the isolated large subunits indeed represent simple [NiFe]-hydrogenase models, which could serve as blueprints for chemically synthesized mimics. Furthermore, our data point to a fundamental role of the small subunit in preventing water access to the catalytic center, which significantly increases the H2 splitting capacity of the enzyme. Spectroscopic investigation of an isolated [NiFe]-hydrogenase large subunit enables a unique view of the NiFe(CO)(CN)2 cofactor.![]()
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Affiliation(s)
- Giorgio Caserta
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Christian Lorent
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Alexandre Ciaccafava
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Matthias Keck
- Department of Chemistry, Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Raffaella Breglia
- Department of Earth and Environmental Sciences, Milano-Bicocca University Piazza della Scienza 1 20126 Milan Italy
| | - Claudio Greco
- Department of Earth and Environmental Sciences, Milano-Bicocca University Piazza della Scienza 1 20126 Milan Italy
| | - Christian Limberg
- Department of Chemistry, Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Peter Hildebrandt
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | | | - Ingo Zebger
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Oliver Lenz
- Institut für Chemie, Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
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18
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Albina P, Durban N, Bertron A, Albrecht A, Robinet JC, Erable B. Influence of Hydrogen Electron Donor, Alkaline pH, and High Nitrate Concentrations on Microbial Denitrification: A Review. Int J Mol Sci 2019; 20:ijms20205163. [PMID: 31635215 PMCID: PMC6834205 DOI: 10.3390/ijms20205163] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/02/2019] [Accepted: 10/15/2019] [Indexed: 12/25/2022] Open
Abstract
Bacterial respiration of nitrate is a natural process of nitrate reduction, which has been industrialized to treat anthropic nitrate pollution. This process, also known as “microbial denitrification”, is widely documented from the fundamental and engineering points of view for the enhancement of the removal of nitrate in wastewater. For this purpose, experiments are generally conducted with heterotrophic microbial metabolism, neutral pH and moderate nitrate concentrations (<50 mM). The present review focuses on a different approach as it aims to understand the effects of hydrogenotrophy, alkaline pH and high nitrate concentration on microbial denitrification. Hydrogen has a high energy content but its low solubility, 0.74 mM (1 atm, 30 °C), in aqueous medium limits its bioavailability, putting it at a kinetic disadvantage compared to more soluble organic compounds. For most bacteria, the optimal pH varies between 7.5 and 9.5. Outside this range, denitrification is slowed down and nitrite (NO2−) accumulates. Some alkaliphilic bacteria are able to express denitrifying activity at pH levels close to 12 thanks to specific adaptation and resistance mechanisms detailed in this manuscript, and some bacterial populations support nitrate concentrations in the range of several hundred mM to 1 M. A high concentration of nitrate generally leads to an accumulation of nitrite. Nitrite accumulation can inhibit bacterial activity and may be a cause of cell death.
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Affiliation(s)
- Pierre Albina
- Laboratoire Matériaux et Durabilité des Constructions, Université de Toulouse, UPS, INSA. 135, 7 avenue de Rangueil, 31077 Toulouse CEDEX 04, France.
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, 31030 Toulouse, France.
| | - Nadège Durban
- Laboratoire Matériaux et Durabilité des Constructions, Université de Toulouse, UPS, INSA. 135, 7 avenue de Rangueil, 31077 Toulouse CEDEX 04, France.
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, 31030 Toulouse, France.
| | - Alexandra Bertron
- Laboratoire Matériaux et Durabilité des Constructions, Université de Toulouse, UPS, INSA. 135, 7 avenue de Rangueil, 31077 Toulouse CEDEX 04, France.
| | - Achim Albrecht
- Andra (Agence nationale pour la gestion des déchets radioactifs), 92298 Châtenay-Malabry, France.
| | - Jean-Charles Robinet
- Andra (Agence nationale pour la gestion des déchets radioactifs), 92298 Châtenay-Malabry, France.
| | - Benjamin Erable
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, 31030 Toulouse, France.
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19
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Liang Y, Cai R, Hickey DP, Kitt JP, Harris JM, Minteer SD, Korzeniewski C. Infrared Microscopy as a Probe of Composition within a Model Biofuel Cell Electrode Prepared from
Trametes versicolor
Laccase. ChemElectroChem 2018. [DOI: 10.1002/celc.201801178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Ying Liang
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409-1061 USA
| | - Rong Cai
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - David P. Hickey
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - Jay P. Kitt
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - Joel M. Harris
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | | | - Carol Korzeniewski
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409-1061 USA
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
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20
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Abstract
Redox enzymes, which catalyze reactions involving electron transfers in living organisms, are very promising components of biotechnological devices, and can be envisioned for sensing applications as well as for energy conversion. In this context, one of the most significant challenges is to achieve efficient direct electron transfer by tunneling between enzymes and conductive surfaces. Based on various examples of bioelectrochemical studies described in the recent literature, this review discusses the issue of enzyme immobilization at planar electrode interfaces. The fundamental importance of controlling enzyme orientation, how to obtain such orientation, and how it can be verified experimentally or by modeling are the three main directions explored. Since redox enzymes are sizable proteins with anisotropic properties, achieving their functional immobilization requires a specific and controlled orientation on the electrode surface. All the factors influenced by this orientation are described, ranging from electronic conductivity to efficiency of substrate supply. The specificities of the enzymatic molecule, surface properties, and dipole moment, which in turn influence the orientation, are introduced. Various ways of ensuring functional immobilization through tuning of both the enzyme and the electrode surface are then described. Finally, the review deals with analytical techniques that have enabled characterization and quantification of successful achievement of the desired orientation. The rich contributions of electrochemistry, spectroscopy (especially infrared spectroscopy), modeling, and microscopy are featured, along with their limitations.
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21
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Ash PA, Carr SB, Reeve HA, Skorupskaitė A, Rowbotham JS, Shutt R, Frogley MD, Evans RM, Cinque G, Armstrong FA, Vincent KA. Generating single metalloprotein crystals in well-defined redox states: electrochemical control combined with infrared imaging of a NiFe hydrogenase crystal. Chem Commun (Camb) 2018; 53:5858-5861. [PMID: 28504793 PMCID: PMC5708527 DOI: 10.1039/c7cc02591b] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We describe an approach to generating and verifying well-defined redox states in metalloprotein single crystals by combining electrochemical control with synchrotron infrared microspectroscopic imaging. For NiFe hydrogenase 1 from Escherichia coli we demonstrate fully reversible and uniform electrochemical reduction from the oxidised inactive to the fully reduced state, and temporally resolve steps during this reduction.
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Affiliation(s)
- P A Ash
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - S B Carr
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK and Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - H A Reeve
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - A Skorupskaitė
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - J S Rowbotham
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - R Shutt
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - M D Frogley
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, UK
| | - R M Evans
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - G Cinque
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, UK
| | - F A Armstrong
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
| | - K A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
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22
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Abstract
Obtaining abundant pure hydrogen by reduction of water has an important implication in the development of clean and renewable energy. Hence research focused on the development of non-noble metal based facile and energy efficient catalysts for proton reduction is on the rise. However, for practical utilization, it is necessary that these complexes function unabated in the presence of atmospheric oxygen and other common contaminants in abundant water sources. There has been very little activity towards the development of oxygen-tolerant hydrogen producing catalysts. This article aims to draw attention to this issue of oxygen sensitivity in the HER and highlights the development of a few air-stable HER catalysts (enzymatic as well as artificial) elaborating the challenges involved and the techniques discovered to overcome this significant deterrent to large-scale hydrogen production by electrolysis from abundant water sources.
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Affiliation(s)
- Biswajit Mondal
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A&2B Raja S.C. Mullick Road, Jadavpur, Kolkata-700032, India.
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23
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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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PEREIRA ANDRESSAR, SEDENHO GRAZIELAC, SOUZA JOÃOCPDE, CRESPILHO FRANKN. Advances in enzyme bioelectrochemistry. ACTA ACUST UNITED AC 2018; 90:825-857. [DOI: 10.1590/0001-3765201820170514] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/11/2017] [Indexed: 11/21/2022]
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Ash PA, Hidalgo R, Vincent KA. Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase. J Vis Exp 2017:55858. [PMID: 29286464 PMCID: PMC5755520 DOI: 10.3791/55858] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Understanding the chemistry of redox proteins demands methods that provide precise control over redox centers within the protein. The technique of protein film electrochemistry, in which a protein is immobilized on an electrode surface such that the electrode replaces physiological electron donors or acceptors, has provided functional insight into the redox reactions of a range of different proteins. Full chemical understanding requires electrochemical control to be combined with other techniques that can add additional structural and mechanistic insight. Here we demonstrate a technique, protein film infrared electrochemistry, which combines protein film electrochemistry with infrared spectroscopic sampling of redox proteins. The technique uses a multiple-reflection attenuated total reflectance geometry to probe a redox protein immobilized on a high surface area carbon black electrode. Incorporation of this electrode into a flow cell allows solution pH or solute concentrations to be changed during measurements. This is particularly powerful in addressing redox enzymes, where rapid catalytic turnover can be sustained and controlled at the electrode allowing spectroscopic observation of long-lived intermediate species in the catalytic mechanism. We demonstrate the technique with experiments on E. coli hydrogenase 1 under turnover (H2 oxidation) and non-turnover conditions.
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Affiliation(s)
- Philip A Ash
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory
| | - Ricardo Hidalgo
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory;
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Zorin NA, Zabelin AA, Shkuropatov AY, Tsygankov AA. Interaction of HydSL hydrogenase from Thiocapsa roseopersicina with cyanide leads to destruction of iron-sulfur clusters. J Inorg Biochem 2017; 177:190-197. [PMID: 28972933 DOI: 10.1016/j.jinorgbio.2017.09.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 11/18/2022]
Abstract
The effects of cyanide on enzymatic activity and absorption spectra in the visible and mid-IR (2150-1850cm-1) regions were characterized for purified HydSL hydrogenase from the purple sulfur bacterium Thiocapsa (T.) roseopersicina BBS. Prolonged incubation (over hours) of T. roseopersicina hydrogenase with exogenous cyanide was shown to result in an irreversible loss of activity of the enzyme in both the oxidized (as isolated) and H2-reduced states. The frequency position of the active site CO and CN- ligand stretching bands in the Fourier transform infrared (FTIR) spectrum of the oxidized form of hydrogenase was not influenced by cyanide treatment. The 410-nm absorption band characteristic of hydrogenase iron‑sulfur clusters showed a bleaching concomitantly with cyanide inactivation. A new band at 2038cm-1 was present in the FTIR spectrum of the cyanide-inactivated preparation, which band is assignable to ferrocyanide as a possible product of a destructive interaction of hydrogenase with cyanide. The results are interpreted in terms of a slow destruction of iron‑sulfur clusters of hydrogenase in the presence of cyanide accompanied by a release of iron ions in the form of ferrocyanide into the surrounding solution. Such a slow and irreversible cyanide-dependent inactivation seems to be complementary to a recently described rapid, reversible inhibitory reaction of cyanide with the active site of hydrogenases [S.V. Hexter, M.-W. Chung, K.A. Vincent, F.A. Armstrong, J. Am. Chem. Soc. 136 (2014) 10470-10477].
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Affiliation(s)
- Nikolay A Zorin
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation
| | - Alexey A Zabelin
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation
| | - Anatoly Ya Shkuropatov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation.
| | - Anatoly A Tsygankov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation
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Ash PA, Hidalgo R, Vincent KA. Proton Transfer in the Catalytic Cycle of [NiFe] Hydrogenases: Insight from Vibrational Spectroscopy. ACS Catal 2017; 7:2471-2485. [PMID: 28413691 PMCID: PMC5387674 DOI: 10.1021/acscatal.6b03182] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/30/2017] [Indexed: 12/11/2022]
Abstract
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Catalysis
of H2 production and oxidation reactions is
critical in renewable energy systems based around H2 as
a clean fuel, but the present reliance on platinum-based catalysts
is not sustainable. In nature, H2 is oxidized at minimal
overpotential and high turnover frequencies at [NiFe] catalytic sites
in hydrogenase enzymes. Although an outline mechanism has been established
for the [NiFe] hydrogenases involving heterolytic cleavage of H2 followed by a first and then second transfer of a proton
and electron away from the active site, details remain vague concerning
how the proton transfers are facilitated by the protein environment
close to the active site. Furthermore, although [NiFe] hydrogenases
from different organisms or cellular environments share a common active
site, they exhibit a broad range of catalytic characteristics indicating
the importance of subtle changes in the surrounding protein in controlling
their behavior. Here we review recent time-resolved infrared (IR)
spectroscopic studies and IR spectroelectrochemical studies carried
out in situ during electrocatalytic turnover. Additionally, we re-evaluate
the significant body of IR spectroscopic data on hydrogenase active
site states determined through more conventional solution studies,
in order to highlight mechanistic steps that seem to apply generally
across the [NiFe] hydrogenases, as well as steps which so far seem
limited to specific groups of these enzymes. This analysis is intended
to help focus attention on the key open questions where further work
is needed to assess important aspects of proton and electron transfer
in the mechanism of [NiFe] hydrogenases.
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Affiliation(s)
- Philip A. Ash
- Department
of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Ricardo Hidalgo
- Department
of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Kylie A. Vincent
- Department
of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom
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Ash P, Reeve HA, Quinson J, Hidalgo R, Zhu T, McPherson IJ, Chung MW, Healy AJ, Nayak S, Lonsdale TH, Wehbe K, Kelley CS, Frogley MD, Cinque G, Vincent KA. Synchrotron-Based Infrared Microanalysis of Biological Redox Processes under Electrochemical Control. Anal Chem 2016; 88:6666-71. [PMID: 27269716 PMCID: PMC4935962 DOI: 10.1021/acs.analchem.6b00898] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/07/2016] [Indexed: 11/30/2022]
Abstract
We describe a method for addressing redox enzymes adsorbed on a carbon electrode using synchrotron infrared microspectroscopy combined with protein film electrochemistry. Redox enzymes have high turnover frequencies, typically 10-1000 s(-1), and therefore, fast experimental triggers are needed in order to study subturnover kinetics and identify the involvement of transient species important to their catalytic mechanism. In an electrochemical experiment, this equates to the use of microelectrodes to lower the electrochemical cell constant and enable changes in potential to be applied very rapidly. We use a biological cofactor, flavin mononucleotide, to demonstrate the power of synchrotron infrared microspectroscopy relative to conventional infrared methods and show that vibrational spectra with good signal-to-noise ratios can be collected for adsorbed species with low surface coverages on microelectrodes with a geometric area of 25 × 25 μm(2). We then demonstrate the applicability of synchrotron infrared microspectroscopy to adsorbed proteins by reporting potential-induced changes in the flavin mononucleotide active site of a flavoenzyme. The method we describe will allow time-resolved spectroscopic studies of chemical and structural changes at redox sites within a variety of proteins under precise electrochemical control.
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Affiliation(s)
- Philip
A. Ash
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Holly A. Reeve
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Jonathan Quinson
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Ricardo Hidalgo
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Tianze Zhu
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Ian J. McPherson
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Min-Wen Chung
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Adam J. Healy
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Simantini Nayak
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Thomas H. Lonsdale
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
| | - Katia Wehbe
- Diamond
Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Chris S. Kelley
- Diamond
Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Mark D. Frogley
- Diamond
Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Gianfelice Cinque
- Diamond
Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Kylie A. Vincent
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QR, United Kingdom
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