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Haase A, Arlt C, Sinz A, Sawers RG. Evidence the Isc iron-sulfur cluster biogenesis machinery is the source of iron for [NiFe]-cofactor biosynthesis in Escherichia coli. Sci Rep 2024; 14:3026. [PMID: 38321125 PMCID: PMC10847431 DOI: 10.1038/s41598-024-53745-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 02/04/2024] [Indexed: 02/08/2024] Open
Abstract
[NiFe]-hydrogenases have a bimetallic NiFe(CN)2CO cofactor in their large, catalytic subunit. The 136 Da Fe(CN)2CO group of this cofactor is preassembled on a distinct HypC-HypD scaffold complex, but the intracellular source of the iron ion is unresolved. Native mass spectrometric analysis of HypCD complexes defined the [4Fe-4S] cluster associated with HypD and identified + 26 to 28 Da and + 136 Da modifications specifically associated with HypC. A HypCC2A variant without the essential conserved N-terminal cysteine residue dissociated from its complex with native HypD lacked all modifications. Native HypC dissociated from HypCD complexes isolated from Escherichia coli strains deleted for the iscS or iscU genes, encoding core components of the Isc iron-sulfur cluster biogenesis machinery, specifically lacked the + 136 Da modification, but this was retained on HypC from suf mutants. The presence or absence of the + 136 Da modification on the HypCD complex correlated with the hydrogenase enzyme activity profiles of the respective mutant strains. Notably, the [4Fe-4S] cluster on HypD was identified in all HypCD complexes analyzed. These results suggest that the iron of the Fe(CN)2CO group on HypCD derives from the Isc machinery, while either the Isc or the Suf machinery can deliver the [4Fe-4S] cluster to HypD.
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Affiliation(s)
- Alexander Haase
- Institute of Biology/ Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
| | - Christian Arlt
- Institute of Pharmacy, Center for Structural Mass Spectrometry, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany
| | - Andrea Sinz
- Institute of Pharmacy, Center for Structural Mass Spectrometry, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany
| | - R Gary Sawers
- Institute of Biology/ Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany.
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2
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Lin L, Huang H, Zhang X, Dong L, Chen Y. Hydrogen-oxidizing bacteria and their applications in resource recovery and pollutant removal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 835:155559. [PMID: 35483467 DOI: 10.1016/j.scitotenv.2022.155559] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/16/2022] [Accepted: 04/23/2022] [Indexed: 06/14/2023]
Abstract
Hydrogen oxidizing bacteria (HOB), a type of chemoautotroph, are a group of bacteria from different genera that share the ability to oxidize H2 and fix CO2 to provide energy and synthesize cellular material. Recently, HOB have received growing attention due to their potential for CO2 capture and waste recovery. This review provides a comprehensive overview of the biological characteristics of HOB and their application in resource recovery and pollutant removal. Firstly, the enzymes, genes and corresponding regulation systems responsible for the key metabolic processes of HOB are discussed in detail. Then, the enrichment and cultivation methods including the coupled water splitting-biosynthetic system cultivation, mixed cultivation and two-stage cultivation strategies for HOB are summarized, which is the critical prerequisite for their application. On the basis, recent advances of HOB application in the recovery of high-value products and the removal of pollutants are presented. Finally, the key points for future investigation are proposed that more attention should be paid to the main limitations in the large-scale industrial application of HOB, including the mass transfer rate of the gases, the safety of the production processes and products, and the commercial value of the products.
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Affiliation(s)
- Lin Lin
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Haining Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xin Zhang
- Shanghai Municipal Engineering Design Institute (Group) Co. LTD, 901 Zhongshan North Second Rd, Shanghai 200092, China
| | - Lei Dong
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Municipal Engineering Design Institute (Group) Co. LTD, 901 Zhongshan North Second Rd, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
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3
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Soboh B, Adrian L, Stripp ST. An in vitro reconstitution system to monitor iron transfer to the active site during the maturation of [NiFe]-hydrogenase. J Biol Chem 2022; 298:102291. [PMID: 35868564 PMCID: PMC9418501 DOI: 10.1016/j.jbc.2022.102291] [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: 06/06/2022] [Revised: 07/13/2022] [Accepted: 07/16/2022] [Indexed: 11/29/2022] Open
Abstract
[NiFe]-hydrogenases comprise a small and a large subunit. The latter harbors the biologically unique [NiFe](CN)2CO active site cofactor. The maturation process includes the assembly of the [Fe](CN)2CO cofactor precursor, nickel binding, endoproteolytic cleavage of the large subunit, and dimerization with the small subunit to yield active enzyme. The biosynthesis of the [Fe](CN)2CO moiety of [NiFe]-Hydrogenase 1 (Hyd-1) and Hyd-2 occurs on the scaffold complex HybG-HypD (GD), whereas the HypC-HypD complex (CD) is specific for the assembly of Hyd-3. The metabolic source and the route for delivering iron to the active site remain unclear. To investigate the maturation process of O2-tolerant Hyd-1 from Escherichia coli, we developed an enzymatic in vitro reconstitution system that allows for the synthesis of Hyd-1 using only purified components. Together with this in vitro reconstitution system, we employed biochemical analyses, infrared spectroscopy (ATR FTIR), mass spectrometry, and microscale thermophoresis (MST) to monitor the iron transfer during the maturation process and to understand how the [Fe](CN)2CO cofactor precursor is ultimately incorporated into the large subunit. We demonstrate the direct transfer of iron from 57Fe-labeled GD complex to the large subunit of Hyd-1. Our data reveal that the GD complex exclusively interacts with the large subunit of Hyd-1 and Hyd-2 but not with the large subunit of Hyd-3. Furthermore, we show that the presence of iron in the active site is a prerequisite for nickel insertion. Taken together, these findings reveal how the [Fe](CN)2CO cofactor precursor is transferred and incorporated into the active site of [NiFe]-hydrogenase.
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Affiliation(s)
- Basem Soboh
- Genetic Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
| | - Lorenz Adrian
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Chair of Geobiotechnology, Technische Universität Berlin, Ackerstraße 76, 13355 Berlin, Germany
| | - Sven T Stripp
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
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4
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Electron inventory of the iron-sulfur scaffold complex HypCD essential in [NiFe]-hydrogenase cofactor assembly. Biochem J 2021; 478:3281-3295. [PMID: 34409988 PMCID: PMC8454700 DOI: 10.1042/bcj20210224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 11/17/2022]
Abstract
The [4Fe-4S] cluster containing scaffold complex HypCD is the central construction site for the assembly of the [Fe](CN)2CO cofactor precursor of [NiFe]-hydrogenase. While the importance of the HypCD complex is well established, not much is known about the mechanism by which the CN- and CO ligands are transferred and attached to the iron ion. We report an efficient expression and purification system producing the HypCD complex from E. coli with complete metal content. This enabled in-depth spectroscopic characterizations. The results obtained by EPR and Mössbauer spectroscopy demonstrate that the [Fe](CN)2CO cofactor and the [4Fe-4S] cluster of the HypCD complex are redox active. The data indicate a potential-dependent interconversion of the [Fe]2+/3+ and [4Fe-4S]2+/+ couple, respectively. Moreover, ATR FTIR spectroscopy reveals potential-dependent disulfide formation, which hints at an electron confurcation step between the metal centers. MicroScale thermophoresis indicates preferable binding between the HypCD complex and its in vivo interaction partner HypE under reducing conditions. Together, these results provide comprehensive evidence for an electron inventory fit to drive multi-electron redox reactions required for the assembly of the CN- and CO ligands on the scaffold complex HypCD.
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5
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Sleutels T, Sebastião Bernardo R, Kuntke P, Janssen M, Buisman CJN, Hamelers HVM. Enhanced Phototrophic Biomass Productivity through Supply of Hydrogen Gas. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2020; 7:861-865. [PMID: 33195732 PMCID: PMC7659310 DOI: 10.1021/acs.estlett.0c00718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
Industrial production of phototrophic microorganisms is often hindered by low productivity due to limited light availability and therefore requires large land areas. This letter demonstrates that supply of hydrogen gas (H2) increases in phototrophic biomass productivity compared to a culture growing on light only. Experiments were performed growing Synechocystis sp. in batch bottles, with and without H2 in the headspace, which were exposed to light intensities of 70 and 100 μmol/m2/s. At 70 μmol/m2/s with H2, the average increase in biomass was 96 mg DW/L/d, whereas at 100 μmol/m2/s without H2, the average increase in biomass was 27 mg DW/L/d. Even at lower light intensity, the addition of H2 tripled the biomass yield compared to growth under light only. Photoreduction and photosynthesis occurred simultaneously, as both H2 consumption and O2 production were measured during biomass growth. Photoreduction used 1.85 mmol of H2 to produce 1.0 mmol of biomass, while photosynthesis produced 1.95 mmol of biomass. After transferring the culture to the dark, growth ceased, also in the presence of H2, showing that both light and H2 were needed for growth. A renewable H2 supply for higher biomass productivity is attractive since the combined efficiency of photovoltaics and electrolysis exceeds the photosynthetic efficiency.
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Affiliation(s)
- Tom Sleutels
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911MA, The
Netherlands
| | - Rita Sebastião Bernardo
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911MA, The
Netherlands
| | - Philipp Kuntke
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911MA, The
Netherlands
- Environmental
Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Marcel Janssen
- Bioprocess
Engineering, AlgaePARC, Wageningen University, P.O. Box 16, 6700 AA Wageningen, The Netherlands
| | - Cees J. N. Buisman
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911MA, The
Netherlands
- Environmental
Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Hubertus V. M. Hamelers
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911MA, The
Netherlands
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6
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Structural Insight into [NiFe] Hydrogenase Maturation by Transient Complexes between Hyp Proteins. Acc Chem Res 2020; 53:875-886. [PMID: 32227866 DOI: 10.1021/acs.accounts.0c00022] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
[NiFe] hydrogenases catalyze reversible hydrogen production/consumption. The core unit of [NiFe] hydrogenase consists of a large and a small subunit. The active site of the large subunit of [NiFe] hydrogenases contains a NiFe(CN)2CO cluster. The biosynthesis/maturation of these hydrogenases is a complex and dynamic process catalyzed primarily by six Hyp proteins (HypABCDEF), which play central roles in the maturation process. HypA and HypB are involved in the Ni insertion, whereas HypC, D, E, and F are required for the biosynthesis, assembly, and insertion of the Fe(CN)2CO group. HypE and HypF catalyze the synthesis of the CN group through the carbamoylation and cyanation of the C-terminus cysteine of HypE. HypC and HypD form a scaffold for the assembly of the Fe(CN)2CO moiety.Over the last decades, a large number of biochemical studies on maturation proteins have been performed, revealing basic functions of each Hyp protein and the overall framework of the maturation pathway. However, it is only in the last 10 years that structural insight has been gained, and our group has made significant contributions to the structural biology of hydrogenase maturation proteins.Since our first publication, where crystal structures of three Hyp proteins have been determined, we have performed a series of structural studies of all six Hyp proteins from a hyperthermophilic archaeon Thermococcus kodakarensis, providing molecular details of each Hyp protein. We have also determined the crystal structures of transient complexes between Hyp proteins that are formed during the maturation process to sequentially incorporate the components of the NiFe(CN)2CO cluster to immature large subunits of [NiFe] hydrogenases. Such complexes, whose crystal structures are determined, include HypA-HypB, HypA-HyhL (hydrogenase large subunit), HypC-HypD, and HypC-HypD-HypE. The structures of the HypC-HypD, and HypCDE complexes reveal a sophisticated process of transient formation of the HypCDE complex, providing insight into the molecular basis of Fe atom cyanation. The high-resolution structures of the carbamoylated and cyanated forms of HypE reveal a structural basis for the biological conversion of primary amide to nitrile. The structure of the HypA-HypB complex elucidates nucleotide-dependent transient complex formation between these two proteins and the molecular basis of acquisition and release of labile Ni. Furthermore, our recent structure analysis of a complex between HypA and immature HyhL reveals that spatial rearrangement of both the N- and C-terminal tails of HyhL will occur upon the [NiFe] cluster insertion, which function as a key checkpoint for the maturation completion. This Account will focus on recent advances in structural studies of the Hyp proteins and on mechanistic insights into the [NiFe] hydrogenase maturation.
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7
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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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Abstract
Numerous recent developments in the biochemistry, molecular biology, and physiology of formate and H2 metabolism and of the [NiFe]-hydrogenase (Hyd) cofactor biosynthetic machinery are highlighted. Formate export and import by the aquaporin-like pentameric formate channel FocA is governed by interaction with pyruvate formate-lyase, the enzyme that generates formate. Formate is disproportionated by the reversible formate hydrogenlyase (FHL) complex, which has been isolated, allowing biochemical dissection of evolutionary parallels with complex I of the respiratory chain. A recently identified sulfido-ligand attached to Mo in the active site of formate dehydrogenases led to the proposal of a modified catalytic mechanism. Structural analysis of the homologous, H2-oxidizing Hyd-1 and Hyd-5 identified a novel proximal [4Fe-3S] cluster in the small subunit involved in conferring oxygen tolerance to the enzymes. Synthesis of Salmonella Typhimurium Hyd-5 occurs aerobically, which is novel for an enterobacterial Hyd. The O2-sensitive Hyd-2 enzyme has been shown to be reversible: it presumably acts as a conformational proton pump in the H2-oxidizing mode and is capable of coupling reverse electron transport to drive H2 release. The structural characterization of all the Hyp maturation proteins has given new impulse to studies on the biosynthesis of the Fe(CN)2CO moiety of the [NiFe] cofactor. It is synthesized on a Hyp-scaffold complex, mainly comprising HypC and HypD, before insertion into the apo-large subunit. Finally, clear evidence now exists indicating that Escherichia coli can mature Hyd enzymes differentially, depending on metal ion availability and the prevailing metabolic state. Notably, Hyd-3 of the FHL complex takes precedence over the H2-oxidizing enzymes.
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9
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Senger M, Stripp ST, Soboh B. Proteolytic cleavage orchestrates cofactor insertion and protein assembly in [NiFe]-hydrogenase biosynthesis. J Biol Chem 2017; 292:11670-11681. [PMID: 28539366 DOI: 10.1074/jbc.m117.788125] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/23/2017] [Indexed: 01/07/2023] Open
Abstract
Metalloenzymes catalyze complex and essential processes, such as photosynthesis, respiration, and nitrogen fixation. For example, bacteria and archaea use [NiFe]-hydrogenases to catalyze the uptake and release of molecular hydrogen (H2). [NiFe]-hydrogenases are redox enzymes composed of a large subunit that harbors a NiFe(CN)2CO metallo-center and a small subunit with three iron-sulfur clusters. The large subunit is synthesized with a C-terminal extension, cleaved off by a specific endopeptidase during maturation. The exact role of the C-terminal extension has remained elusive; however, cleavage takes place exclusively after assembly of the [NiFe]-cofactor and before large and small subunits form the catalytically active heterodimer. To unravel the functional role of the C-terminal extension, we used an enzymatic in vitro maturation assay that allows synthesizing functional [NiFe]-hydrogenase-2 of Escherichia coli from purified components. The maturation process included formation and insertion of the NiFe(CN)2CO cofactor into the large subunit, endoproteolytic cleavage of the C-terminal extension, and dimerization with the small subunit. Biochemical and spectroscopic analysis indicated that the C-terminal extension of the large subunit is essential for recognition by the maturation machinery. Only upon completion of cofactor insertion was removal of the C-terminal extension observed. Our results indicate that endoproteolytic cleavage is a central checkpoint in the maturation process. Here, cleavage temporally orchestrates cofactor insertion and protein assembly and ensures that only cofactor-containing protein can continue along the assembly line toward functional [NiFe]-hydrogenase.
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Affiliation(s)
- Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universitaet Berlin, 14195 Berlin, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universitaet Berlin, 14195 Berlin, Germany
| | - Basem Soboh
- Department of Physics, Experimental Molecular Biophysics, Freie Universitaet Berlin, 14195 Berlin, Germany.
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10
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Adamson H, Robinson M, Bond PS, Soboh B, Gillow K, Simonov AN, Elton DM, Bond AM, Sawers RG, Gavaghan DJ, Parkin A. Analysis of HypD Disulfide Redox Chemistry via Optimization of Fourier Transformed ac Voltammetric Data. Anal Chem 2017; 89:1565-1573. [PMID: 28029041 DOI: 10.1021/acs.analchem.6b03589] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rapid disulfide bond formation and cleavage is an essential mechanism of life. Using large amplitude Fourier transformed alternating current voltammetry (FTacV) we have measured previously uncharacterized disulfide bond redox chemistry in Escherichia coli HypD. This protein is representative of a class of assembly proteins that play an essential role in the biosynthesis of the active site of [NiFe]-hydrogenases, a family of H2-activating enzymes. Compared to conventional electrochemical methods, the advantages of the FTacV technique are the high resolution of the faradaic signal in the higher order harmonics and the fact that a single electrochemical experiment contains all the data needed to estimate the (very fast) electron transfer rates (both rate constants ≥ 4000 s-1) and quantify the energetics of the cysteine disulfide redox-reaction (reversible potentials for both processes approximately -0.21 ± 0.01 V vs SHE at pH 6). Previously, deriving such data depended on an inefficient manual trial-and-error approach to simulation. As a highly advantageous alternative, we describe herein an automated multiparameter data optimization analysis strategy where the simulated and experimental faradaic current data are compared for both the real and imaginary components in each of the 4th to 12th harmonics after quantifying the charging current data using the time-domain response.
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Affiliation(s)
- Hope Adamson
- Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom
| | - Martin Robinson
- Department of Computer Science, University of Oxford , Wolfson Building, Parks Road, Oxford, OX1 3QD, United Kingdom
| | - Paul S Bond
- Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom
| | - Basem Soboh
- Experimental Molecular Biophysics, Freie Universität Berlin , Arnimalle 14, 14195 Berlin, Germany
| | - Kathryn Gillow
- Mathematical Institute, Andrew Wiles Building, University of Oxford , Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, United Kingdom
| | - Alexandr N Simonov
- School of Chemistry and the ARC Centre of Excellence for Electromaterials Science, Monash University , Clayton, Victoria 3800, Australia
| | - Darrell M Elton
- School of Engineering and Mathematical Sciences, La Trobe University , Bundoora, Victoria 3086, Australia
| | - Alan M Bond
- School of Chemistry and the ARC Centre of Excellence for Electromaterials Science, Monash University , Clayton, Victoria 3800, Australia
| | - R Gary Sawers
- Institute for Biology/Microbiology, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
| | - David J Gavaghan
- Department of Computer Science, University of Oxford , Wolfson Building, Parks Road, Oxford, OX1 3QD, United Kingdom
| | - Alison Parkin
- Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom
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11
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Biosynthesis of Salmonella enterica [NiFe]-hydrogenase-5: probing the roles of system-specific accessory proteins. J Biol Inorg Chem 2016; 21:865-73. [PMID: 27566174 DOI: 10.1007/s00775-016-1385-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/04/2016] [Indexed: 10/21/2022]
Abstract
A subset of bacterial [NiFe]-hydrogenases have been shown to be capable of activating dihydrogen-catalysis under aerobic conditions; however, it remains relatively unclear how the assembly and activation of these enzymes is carried out in the presence of air. Acquiring this knowledge is important if a generic method for achieving production of O2-resistant [NiFe]-hydrogenases within heterologous hosts is to be developed. Salmonella enterica serovar Typhimurium synthesizes the [NiFe]-hydrogenase-5 (Hyd-5) enzyme under aerobic conditions. As well as structural genes, the Hyd-5 operon also contains several accessory genes that are predicted to be involved in different stages of biosynthesis of the enzyme. In this work, deletions in the hydF, hydG, and hydH genes have been constructed. The hydF gene encodes a protein related to Ralstonia eutropha HoxO, which is known to interact with the small subunit of a [NiFe]-hydrogenase. HydG is predicted to be a fusion of the R. eutropha HoxQ and HoxR proteins, both of which have been implicated in the biosynthesis of an O2-tolerant hydrogenase, and HydH is a homologue of R. eutropha HoxV, which is a scaffold for [NiFe] cofactor assembly. It is shown here that HydG and HydH play essential roles in Hyd-5 biosynthesis. Hyd-5 can be isolated and characterized from a ΔhydF strain, indicating that HydF may not play the same vital role as the orthologous HoxO. This study, therefore, emphasises differences that can be observed when comparing the function of hydrogenase maturases in different biological systems.
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12
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Abstract
[NiFe]-hydrogenases catalyze the reversible conversion of hydrogen gas into protons and electrons and are vital metabolic components of many species of bacteria and archaea. At the core of this enzyme is a sophisticated catalytic center comprising nickel and iron, as well as cyanide and carbon monoxide ligands, which is anchored to the large hydrogenase subunit through cysteine residues. The production of this multicomponent active site is accomplished by a collection of accessory proteins and can be divided into discrete stages. The iron component is fashioned by the proteins HypC, HypD, HypE, and HypF, which functionalize iron with cyanide and carbon monoxide. Insertion of the iron center signals to the metallochaperones HypA, HypB, and SlyD to selectively deliver the nickel to the active site. A specific protease recognizes the completed metal cluster and then cleaves the C-terminus of the large subunit, resulting in a conformational change that locks the active site in place. Finally, the large subunit associates with the small subunit, and the complete holoenzyme translocates to its final cellular position. Beyond this broad overview of the [NiFe]-hydrogenase maturation process, biochemical and structural studies are revealing the fundamental underlying molecular mechanisms. Here, we review recent work illuminating how the accessory proteins contribute to the maturation of [NiFe]-hydrogenase and discuss some of the outstanding questions that remain to be resolved.
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Affiliation(s)
- Michael J Lacasse
- Department of Chemistry, University of Toronto , Toronto, Ontario, Canada M5S 3H6
| | - Deborah B Zamble
- Department of Chemistry, University of Toronto , Toronto, Ontario, Canada M5S 3H6.,Department of Biochemistry, University of Toronto , Toronto, Ontario, Canada M5S 1A8
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13
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14
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Stripp ST, Lindenstrauss U, Sawers RG, Soboh B. Identification of an Isothiocyanate on the HypEF Complex Suggests a Route for Efficient Cyanyl-Group Channeling during [NiFe]-Hydrogenase Cofactor Generation. PLoS One 2015; 10:e0133118. [PMID: 26186649 PMCID: PMC4506123 DOI: 10.1371/journal.pone.0133118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 06/24/2015] [Indexed: 01/12/2023] Open
Abstract
[NiFe]–hydrogenases catalyze uptake and evolution of H2 in a wide range of microorganisms. The enzyme is characterized by an inorganic nickel/ iron cofactor, the latter of which carries carbon monoxide and cyanide ligands. In vivo generation of these ligands requires a number of auxiliary proteins, the so–called Hyp family. Initially, HypF binds and activates the precursor metabolite carbamoyl phosphate. HypF catalyzes removal of phosphate and transfers the carbamate group to HypE. In an ATP–dependent condensation reaction, the C–terminal cysteinyl residue of HypE is modified to what has been interpreted as thiocyanate. This group is the direct precursor of the cyanide ligands of the [NiFe]–hydrogenase active site cofactor. We present a FT–IR analysis of HypE and HypF as isolated from E. coli. We follow the HypF–catalyzed cyanation of HypE in vitro and screen for the influence of carbamoyl phosphate and ATP. To elucidate on the differences between HypE and the HypEF complex, spectro–electrochemistry was used to map the vibrational Stark effect of naturally cyanated HypE. The IR signature of HypE could ultimately be assigned to isothiocyanate (–N=C=S) rather than thiocyanate (–S–C≡N). This has important implications for cyanyl–group channeling during [NiFe]–hydrogenase cofactor generation.
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Affiliation(s)
- Sven T. Stripp
- Department of Physics, Freie Universität Berlin, Berlin, Germany
- * E-mail:
| | - Ute Lindenstrauss
- Institute of Microbiology, Martin–Luther University Halle–Wittenberg, Halle (Saale), Germany
| | - R. Gary Sawers
- Institute of Microbiology, Martin–Luther University Halle–Wittenberg, Halle (Saale), Germany
| | - Basem Soboh
- Institute of Microbiology, Martin–Luther University Halle–Wittenberg, Halle (Saale), Germany
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15
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Schiffels J, Selmer T. A flexible toolbox to study protein-assisted metalloenzyme assembly in vitro. Biotechnol Bioeng 2015; 112:2360-72. [PMID: 25994231 DOI: 10.1002/bit.25658] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/11/2015] [Indexed: 11/06/2022]
Abstract
A number of metalloenzymes harbor unique cofactors, which are incorporated into the apo-enzymes via protein-assisted maturation. In the case of [NiFe]-hydrogenases, minimally seven maturation factors (HypABCDEF and a specific endopeptidase) are involved, making these enzymes an excellent example for studying metallocenter assembly in general. Here, we describe an innovative toolbox to study maturation involving multiple putative gene products. The two core elements of the system are a modular, combinatorial cloning system and a cell-free maturation system, which is based on recombinant Escherichia coli extracts and/or purified maturases. Taking maturation of the soluble, oxygen-tolerant [NiFe]-hydrogenase (SH) from Cupriavidus necator as an example, the capacities of the toolbox are illustrated. In total 18 genes from C. necator were analyzed, including four SH-structural genes, the SH-dedicated hyp-genes and a second set of hyp-genes putatively involved in maturation of the Actinobacterium-like hydrogenase (AH). The two hyp-sets were either expressed in their entirety from single vectors or split into functional modules, which enabled flexible approaches to investigate limitations, specificities and the capabilities of individual constituents to functionally substitute each other. Affinity-tagged Hyp-Proteins were used in pull-down experiments to demonstrate direct interactions between dedicated or non-related constituents. The dedicated Hyp-set from C. necator exhibited the highest maturation efficiency in vitro. Constituents of non-related maturation machineries were found to interact with and to accomplish partial activation of SH. In contrast to homologues of the Hyp-family, omission of the SH-specific endopeptidase HoxW completely abolished in vitro maturation. We detected stoichiometric imbalances inside the recombinant production system, which point to limitations by the cyanylation complex HypEF and the premature subunit HoxH. Purification of HoxW revealed strong indications for the presence of a putative [4Fe-4S]-cluster, which is unique among this class of maturases. Results are discussed in the context of [NiFe]-hydrogenase maturation, and in light of the capacity of the novel toolbox.
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Affiliation(s)
- Johannes Schiffels
- From the Aachen University of Applied Sciences, Campus Juelich, Department of Chemistry and Biotechnology, Heinrich-Mussmann-Str. 1, D-52428 Juelich, Germany
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16
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Khanna N, Lindblad P. Cyanobacterial hydrogenases and hydrogen metabolism revisited: recent progress and future prospects. Int J Mol Sci 2015; 16:10537-61. [PMID: 26006225 PMCID: PMC4463661 DOI: 10.3390/ijms160510537] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 11/25/2022] Open
Abstract
Cyanobacteria have garnered interest as potential cell factories for hydrogen production. In conjunction with photosynthesis, these organisms can utilize inexpensive inorganic substrates and solar energy for simultaneous biosynthesis and hydrogen evolution. However, the hydrogen yield associated with these organisms remains far too low to compete with the existing chemical processes. Our limited understanding of the cellular hydrogen production pathway is a primary setback in the potential scale-up of this process. In this regard, the present review discusses the recent insight around ferredoxin/flavodoxin as the likely electron donor to the bidirectional Hox hydrogenase instead of the generally accepted NAD(P)H. This may have far reaching implications in powering solar driven hydrogen production. However, it is evident that a successful hydrogen-producing candidate would likely integrate enzymatic traits from different species. Engineering the [NiFe] hydrogenases for optimal catalytic efficiency or expression of a high turnover [FeFe] hydrogenase in these photo-autotrophs may facilitate the development of strains to reach target levels of biohydrogen production in cyanobacteria. The fundamental advancements achieved in these fields are also summarized in this review.
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Affiliation(s)
- Namita Khanna
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-75120, Sweden.
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-75120, Sweden.
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