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Omeiri J, Martin L, Usclat A, Cherrier MV, Nicolet Y. Maturation of the [FeFe]-Hydrogenase: Direct Transfer of the (κ 3 -cysteinate)Fe II (CN)(CO) 2 Complex B from HydG to HydE. Angew Chem Int Ed Engl 2023; 62:e202314819. [PMID: 37962296 DOI: 10.1002/anie.202314819] [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: 10/07/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/15/2023]
Abstract
[FeFe]-hydrogenases efficiently catalyze the reversible oxidation of molecular hydrogen. Their prowess stems from the intricate H-cluster, combining a [Fe4 S4 ] center with a binuclear iron center ([2Fe]H ). In the latter, each iron atom is coordinated by a CO and CN ligand, connected by a CO and an azadithiolate ligand. The synthesis of this active site involves a unique multiprotein assembly, featuring radical SAM proteins HydG and HydE. HydG initiates the transformation of L-tyrosine into cyanide and carbon monoxide to generate complex B, which is subsequently transferred to HydE to continue the biosynthesis of the [2Fe]H -subcluster. Due to its instability, complex B isolation for structural or spectroscopic characterization has been elusive thus far. Nevertheless, the use of a biomimetic analogue of complex B allowed circumvention of the need for the HydG protein during in vitro functional investigations, implying a similar structure for complex B. Herein, we used the HydE protein as a nanocage to encapsulate and stabilize the complex B product generated by HydG. Using X-ray crystallography, we successfully determined its structure at 1.3 Å resolution. Furthermore, we demonstrated that complex B is directly transferred from HydG to HydE, thus not being released into the solution post-synthesis, highlighting a transient interaction between the two proteins.
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Affiliation(s)
- Juneina Omeiri
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Lydie Martin
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Anthony Usclat
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Mickael V Cherrier
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Yvain Nicolet
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
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2
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Balci B, O'Neill RD, Shepard EM, Pagnier A, Marlott A, Mock MT, Broderick WE, Broderick JB. Semisynthetic maturation of [FeFe]-hydrogenase using [Fe 2(μ-SH) 2(CN) 2(CO) 4] 2-: key roles for HydF and GTP. Chem Commun (Camb) 2023. [PMID: 37376915 DOI: 10.1039/d3cc02169f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Here we describe maturation of the [FeFe]-hydrogenase from its [4Fe-4S]-bound precursor state by using the synthetic complex [Fe2(μ-SH)2(CN)2(CO)4]2- together with HydF and components of the glycine cleavage system, but in the absence of the maturases HydE and HydG. This semisynthetic and fully-defined maturation provides new insights into the nature of H-cluster biosynthesis.
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Affiliation(s)
- Batuhan Balci
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Roark D O'Neill
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Eric M Shepard
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Adrien Pagnier
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Alexander Marlott
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Michael T Mock
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - William E Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Joan B Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
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3
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Abstract
Radical S-adenosylmethionine (SAM) enzymes use a site-differentiated [4Fe-4S] cluster and SAM to initiate radical reactions through liberation of the 5'-deoxyadenosyl (5'-dAdo•) radical. They form the largest enzyme superfamily, with more than 700,000 unique sequences currently, and their numbers continue to grow as a result of ongoing bioinformatics efforts. The range of extremely diverse, highly regio- and stereo-specific reactions known to be catalyzed by radical SAM superfamily members is remarkable. The common mechanism of radical initiation in the radical SAM superfamily is the focus of this review. Most surprising is the presence of an organometallic intermediate, Ω, exhibiting an Fe-C5'-adenosyl bond. Regioselective reductive cleavage of the SAM S-C5' bond produces 5'-dAdo• to form Ω, with the regioselectivity originating in the Jahn-Teller effect. Ω liberates the free 5'-dAdo• as the catalytically active intermediate through homolysis of the Fe-C5' bond, in analogy to Co-C5' bond homolysis in B12, which was once viewed as biology's choice of radical generator.
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Affiliation(s)
- Brian M Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
| | - William E Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA;
| | - Joan B Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA;
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4
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Abstract
Covering: up to 2022The report provides a broad approach to deciphering the evolution of coenzyme biosynthetic pathways. Here, these various pathways are analyzed with respect to the coenzymes required for this purpose. Coenzymes whose biosynthesis relies on a large number of coenzyme-mediated reactions probably appeared on the scene at a later stage of biological evolution, whereas the biosyntheses of pyridoxal phosphate (PLP) and nicotinamide (NAD+) require little additional coenzymatic support and are therefore most likely very ancient biosynthetic pathways.
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Affiliation(s)
- Andreas Kirschning
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, D-30167 Hannover, Germany.
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5
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Stripp ST, Duffus BR, Fourmond V, Léger C, Leimkühler S, Hirota S, Hu Y, Jasniewski A, Ogata H, Ribbe MW. Second and Outer Coordination Sphere Effects in Nitrogenase, Hydrogenase, Formate Dehydrogenase, and CO Dehydrogenase. Chem Rev 2022; 122:11900-11973. [PMID: 35849738 PMCID: PMC9549741 DOI: 10.1021/acs.chemrev.1c00914] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Gases like H2, N2, CO2, and CO are increasingly recognized as critical feedstock in "green" energy conversion and as sources of nitrogen and carbon for the agricultural and chemical sectors. However, the industrial transformation of N2, CO2, and CO and the production of H2 require significant energy input, which renders processes like steam reforming and the Haber-Bosch reaction economically and environmentally unviable. Nature, on the other hand, performs similar tasks efficiently at ambient temperature and pressure, exploiting gas-processing metalloenzymes (GPMs) that bind low-valent metal cofactors based on iron, nickel, molybdenum, tungsten, and sulfur. Such systems are studied to understand the biocatalytic principles of gas conversion including N2 fixation by nitrogenase and H2 production by hydrogenase as well as CO2 and CO conversion by formate dehydrogenase, carbon monoxide dehydrogenase, and nitrogenase. In this review, we emphasize the importance of the cofactor/protein interface, discussing how second and outer coordination sphere effects determine, modulate, and optimize the catalytic activity of GPMs. These may comprise ionic interactions in the second coordination sphere that shape the electron density distribution across the cofactor, hydrogen bonding changes, and allosteric effects. In the outer coordination sphere, proton transfer and electron transfer are discussed, alongside the role of hydrophobic substrate channels and protein structural changes. Combining the information gained from structural biology, enzyme kinetics, and various spectroscopic techniques, we aim toward a comprehensive understanding of catalysis beyond the first coordination sphere.
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Affiliation(s)
- Sven T Stripp
- Freie Universität Berlin, Experimental Molecular Biophysics, Berlin 14195, Germany
| | | | - Vincent Fourmond
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Christophe Léger
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Silke Leimkühler
- University of Potsdam, Molecular Enzymology, Potsdam 14476, Germany
| | - Shun Hirota
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan
| | - Yilin Hu
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Andrew Jasniewski
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Hideaki Ogata
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan
- Hokkaido University, Institute of Low Temperature Science, Sapporo 060-0819, Japan
- Graduate School of Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Markus W Ribbe
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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6
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Genome-Scale Mining of Acetogens of the Genus Clostridium Unveils Distinctive Traits in [FeFe]- and [NiFe]-Hydrogenase Content and Maturation. Microbiol Spectr 2022; 10:e0101922. [PMID: 35735976 PMCID: PMC9431212 DOI: 10.1128/spectrum.01019-22] [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] [Indexed: 11/20/2022] Open
Abstract
Knowledge of the organizational and functional properties of hydrogen metabolism is pivotal to the construction of a framework supportive of a hydrogen-fueled low-carbon economy. Hydrogen metabolism relies on the mechanism of action of hydrogenases. In this study, we investigated the genomes of several industrially relevant acetogens of the genus Clostridium (C. autoethanogenum, C. ljungdahlii, C. carboxidivorans, C. drakei, C. scatologenes, C. coskatii, C. ragsdalei, C. sp. AWRP) to systematically identify their intriguingly diversified hydrogenases’ repertoire. An entirely computational annotation pipeline unveiled common and strain-specific traits in the functional content of [NiFe]- and [FeFe]-hydrogenases. Hydrogenases were identified and categorized into functionally distinct classes by the combination of sequence homology, with respect to a database of curated nonredundant hydrogenases, with the analysis of sequence patterns characteristic of the mode of action of [FeFe]- and [NiFe]-hydrogenases. The inspection of the genes in the neighborhood of the catalytic subunits unveiled a wide agreement between their genomic arrangement and the gene organization templates previously developed for the predicted hydrogenase classes. Subunits’ characterization of the identified hydrogenases allowed us to glean some insights on the redox cofactor-binding determinants in the diaphorase subunits of the electron-bifurcating [FeFe]-hydrogenases. Finally, the reliability of the inferred hydrogenases was corroborated by the punctual analysis of the maturation proteins necessary for the biosynthesis of [NiFe]- and [FeFe]-hydrogenases. IMPORTANCE Mastering hydrogen metabolism can support a sustainable carbon-neutral economy. Of the many microorganisms metabolizing hydrogen, acetogens of the genus Clostridium are appealing, with some of them already in usage as industrial workhorses. Having provided detailed information on the hydrogenase content of an unprecedented number of clostridial acetogens at the gene level, our study represents a valuable knowledge base to deepen our understanding of hydrogenases’ functional specificity and/or redundancy and to develop a large array of biotechnological processes. We also believe our study could serve as a basis for future strain-engineering approaches, acting at the hydrogenases’ level or at the level of their maturation proteins. On the other side, the wealth of functional elements discussed in relation to the identified hydrogenases is worthy of further investigation by biochemical and structural studies to ultimately lead to the usage of these enzymes as valuable catalysts.
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7
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Pagnier A, Balci B, Shepard EM, Yang H, Warui DM, Impano S, Booker SJ, Hoffman BM, Broderick WE, Broderick JB. [FeFe]-Hydrogenase: Defined Lysate-Free Maturation Reveals a Key Role for Lipoyl-H-Protein in DTMA Ligand Biosynthesis. Angew Chem Int Ed Engl 2022; 61:e202203413. [PMID: 35319808 PMCID: PMC9117470 DOI: 10.1002/anie.202203413] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Indexed: 11/09/2022]
Abstract
Maturation of [FeFe]-hydrogenase (HydA) involves synthesis of a CO, CN- , and dithiomethylamine (DTMA)-coordinated 2Fe subcluster that is inserted into HydA to make the active hydrogenase. This process requires three maturation enzymes: the radical S-adenosyl-l-methionine (SAM) enzymes HydE and HydG, and the GTPase HydF. In vitro maturation with purified maturation enzymes has been possible only when clarified cell lysate was added, with the lysate presumably providing essential components for DTMA synthesis and delivery. Here we report maturation of [FeFe]-hydrogenase using a fully defined system that includes components of the glycine cleavage system (GCS), but no cell lysate. Our results reveal for the first time an essential role for the aminomethyl-lipoyl-H-protein of the GCS in hydrogenase maturation and the synthesis of the DTMA ligand of the H-cluster. In addition, we show that ammonia is the source of the bridgehead nitrogen of DTMA.
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Affiliation(s)
- Adrien Pagnier
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Batuhan Balci
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Eric M Shepard
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Hao Yang
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Douglas M Warui
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Stella Impano
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Squire J Booker
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - William E Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Joan B Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA
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8
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Schaupp S, Arriaza‐Gallardo FJ, Pan H, Kahnt J, Angelidou G, Paczia N, Costa K, Hu X, Shima S. In Vitro Biosynthesis of the [Fe]-Hydrogenase Cofactor Verifies the Proposed Biosynthetic Precursors. Angew Chem Int Ed Engl 2022; 61:e202200994. [PMID: 35286742 PMCID: PMC9314073 DOI: 10.1002/anie.202200994] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Indexed: 02/06/2023]
Abstract
In the FeGP cofactor of [Fe]-hydrogenase, low-spin FeII is in complex with two CO ligands and a pyridinol derivative; the latter ligates the iron with a 6-acylmethyl substituent and the pyridinol nitrogen. A guanylylpyridinol derivative, 6-carboxymethyl-3,5-dimethyl-4-guanylyl-2-pyridinol (3), is produced by the decomposition of the FeGP cofactor under irradiation with UV-A/blue light and is also postulated to be a precursor of FeGP cofactor biosynthesis. HcgC and HcgB catalyze consecutive biosynthesis steps leading to 3. Here, we report an in vitro biosynthesis assay of the FeGP cofactor using the cell extract of the ΔhcgBΔhcgC strain of Methanococcus maripaludis, which does not biosynthesize 3. We chemically synthesized pyridinol precursors 1 and 2, and detected the production of the FeGP cofactor from 1, 2 and 3. These results indicated that 1, 2 and 3 are the precursors of the FeGP cofactor, and the carboxy group of 3 is converted to the acyl ligand.
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Affiliation(s)
- Sebastian Schaupp
- Max Planck Institute for Terrestrial MicrobiologyKarl-von-Frisch-Straße 1035043MarburgGermany
| | | | - Hui‐jie Pan
- Laboratory of Inorganic Synthesis and CatalysisInstitute of Chemical Sciences and EngineeringEcole Polytechnique Fédérale de Lausanne (EPFL) ISIC-LSCI, BCH 33051015LausanneSwitzerland
| | - Jörg Kahnt
- Max Planck Institute for Terrestrial MicrobiologyKarl-von-Frisch-Straße 1035043MarburgGermany
| | - Georgia Angelidou
- Max Planck Institute for Terrestrial MicrobiologyKarl-von-Frisch-Straße 1035043MarburgGermany
| | - Nicole Paczia
- Max Planck Institute for Terrestrial MicrobiologyKarl-von-Frisch-Straße 1035043MarburgGermany
| | - Kyle Costa
- Department of Plant and Microbial BiologyUniversity of MinnesotaTwin CitiesSt. Paul, MNUSA
| | - Xile Hu
- Laboratory of Inorganic Synthesis and CatalysisInstitute of Chemical Sciences and EngineeringEcole Polytechnique Fédérale de Lausanne (EPFL) ISIC-LSCI, BCH 33051015LausanneSwitzerland
| | - Seigo Shima
- Max Planck Institute for Terrestrial MicrobiologyKarl-von-Frisch-Straße 1035043MarburgGermany
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9
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Amara P, Saragaglia C, Mouesca JM, Martin L, Nicolet Y. L-tyrosine-bound ThiH structure reveals C-C bond break differences within radical SAM aromatic amino acid lyases. Nat Commun 2022; 13:2284. [PMID: 35477710 PMCID: PMC9046217 DOI: 10.1038/s41467-022-29980-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 04/05/2022] [Indexed: 11/08/2022] Open
Abstract
2-iminoacetate synthase ThiH is a radical S-adenosyl-L-methionine (SAM) L-tyrosine lyase and catalyzes the L-tyrosine Cα-Cβ bond break to produce dehydroglycine and p-cresol while the radical SAM L-tryptophan lyase NosL cleaves the L-tryptophan Cα-C bond to produce 3-methylindole-2-carboxylic acid. It has been difficult to understand the features that condition one C-C bond break over the other one because the two enzymes display significant primary structure similarities and presumably similar substrate-binding modes. Here, we report the crystal structure of L-tyrosine bound ThiH from Thermosinus carboxydivorans revealing an unusual protonation state of L-tyrosine upon binding. Structural comparison of ThiH with NosL and computational studies of the respective reactions they catalyze show that substrate activation is eased by tunneling effect and that subtle structural changes between the two enzymes affect, in particular, the hydrogen-atom abstraction by the 5´-deoxyadenosyl radical species, driving the difference in reaction specificity.
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Affiliation(s)
- Patricia Amara
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000, Grenoble, France
| | - Claire Saragaglia
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000, Grenoble, France
| | - Jean-Marie Mouesca
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-DIESE-SyMMES-CAMPE, 38000, Grenoble, France
| | - Lydie Martin
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000, Grenoble, France
| | - Yvain Nicolet
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000, Grenoble, France.
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10
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Pagnier A, Balci B, Shepard EM, Yang H, Warui DM, Impano S, Booker SJ, Hoffman BM, Broderick WE, Broderick JB. [FeFe]‐Hydrogenase: Defined Lysate‐Free Maturation Reveals a Key Role for Lipoyl‐H‐Protein in DTMA Ligand Biosynthesis. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Adrien Pagnier
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Batuhan Balci
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Eric M. Shepard
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Hao Yang
- Department of Chemistry Northwestern University Evanston IL 60208 USA
| | - Douglas M. Warui
- Department of Chemistry The Pennsylvania State University University Park PA 16802 USA
| | - Stella Impano
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Squire J. Booker
- Department of Chemistry The Pennsylvania State University University Park PA 16802 USA
- Howard Hughes Medical Institute Chevy Chase MD 20815 USA
| | - Brian M. Hoffman
- Department of Chemistry Northwestern University Evanston IL 60208 USA
| | - William E. Broderick
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Joan B. Broderick
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
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11
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Schaupp S, Arriaza‐Gallardo FJ, Pan H, Kahnt J, Angelidou G, Paczia N, Costa K, Hu X, Shima S. In Vitro Biosynthesis of the [Fe]‐Hydrogenase Cofactor Verifies the Proposed Biosynthetic Precursors. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sebastian Schaupp
- Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch-Straße 10 35043 Marburg Germany
| | | | - Hui‐jie Pan
- Laboratory of Inorganic Synthesis and Catalysis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne (EPFL) ISIC-LSCI, BCH 3305 1015 Lausanne Switzerland
| | - Jörg Kahnt
- Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch-Straße 10 35043 Marburg Germany
| | - Georgia Angelidou
- Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch-Straße 10 35043 Marburg Germany
| | - Nicole Paczia
- Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch-Straße 10 35043 Marburg Germany
| | - Kyle Costa
- Department of Plant and Microbial Biology University of Minnesota Twin Cities St. Paul, MN USA
| | - Xile Hu
- Laboratory of Inorganic Synthesis and Catalysis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne (EPFL) ISIC-LSCI, BCH 3305 1015 Lausanne Switzerland
| | - Seigo Shima
- Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch-Straße 10 35043 Marburg Germany
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12
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King SJ, Jerkovic A, Brown LJ, Petroll K, Willows RD. Synthetic biology for improved hydrogen production in Chlamydomonas reinhardtii. Microb Biotechnol 2022; 15:1946-1965. [PMID: 35338590 PMCID: PMC9249334 DOI: 10.1111/1751-7915.14024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/09/2022] [Accepted: 02/11/2022] [Indexed: 12/04/2022] Open
Abstract
Hydrogen is a clean alternative to fossil fuels. It has applications for electricity generation and transportation and is used for the manufacturing of ammonia and steel. However, today, H2 is almost exclusively produced from coal and natural gas. As such, methods to produce H2 that do not use fossil fuels need to be developed and adopted. The biological manufacturing of H2 may be one promising solution as this process is clean and renewable. Hydrogen is produced biologically via enzymes called hydrogenases. There are three classes of hydrogenases namely [FeFe], [NiFe] and [Fe] hydrogenases. The [FeFe] hydrogenase HydA1 from the model unicellular algae Chlamydomonas reinhardtii has been studied extensively and belongs to the A1 subclass of [FeFe] hydrogenases that have the highest turnover frequencies amongst hydrogenases (21,000 ± 12,000 H2 s−1 for CaHydA from Clostridium acetobutyliticum). Yet to date, limitations in C. reinhardtii H2 production pathways have hampered commercial scale implementation, in part due to O2 sensitivity of hydrogenases and competing metabolic pathways, resulting in low H2 production efficiency. Here, we describe key processes in the biogenesis of HydA1 and H2 production pathways in C. reinhardtii. We also summarize recent advancements of algal H2 production using synthetic biology and describe valuable tools such as high‐throughput screening (HTS) assays to accelerate the process of engineering algae for commercial biological H2 production.
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Affiliation(s)
- Samuel J King
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ante Jerkovic
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Louise J Brown
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Kerstin Petroll
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Robert D Willows
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
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13
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Britt RD, Tao L, Rao G, Chen N, Wang LP. Proposed Mechanism for the Biosynthesis of the [FeFe] Hydrogenase H-Cluster: Central Roles for the Radical SAM Enzymes HydG and HydE. ACS BIO & MED CHEM AU 2022; 2:11-21. [PMID: 35187536 PMCID: PMC8855341 DOI: 10.1021/acsbiomedchemau.1c00035] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 01/05/2023]
Abstract
Radical S-adenosylmethionine (radical SAM or rSAM) enzymes use their S-adenosylmethionine cofactor bound to a unique Fe of a [4Fe-4S] cluster to generate the "hot" 5'-deoxyadenosyl radical, which drives highly selective radical reactions via specific interactions with a given rSAM enzyme's substrate. This Perspective focuses on the two rSAM enzymes involved in the biosynthesis of the organometallic H-cluster of [FeFe] hydrogenases. We present here a detailed sequential model initiated by HydG, which lyses a tyrosine substrate via a 5'-deoxyadenosyl H atom abstraction from those amino acid's amino group, initially producing dehydroglycine and an oxidobenzyl radical. In this model, two successive radical cascade reactions lead ultimately to the formation of HydG's product, a mononuclear Fe organometallic complex: [Fe(II)(CN)(CO)2(cysteinate)]-, with the iron originating from a unique "dangler" Fe coordinated by a cysteine ligand providing a sulfur bridge to another [4Fe-4S] auxiliary cluster in the enzyme. In turn, in this model, [Fe(II)(CN)(CO)2(cysteinate)]- is the substrate for HydE, the second rSAM enzyme in the biosynthetic pathway, which activates this mononuclear organometallic unit for dimerization, forming a [Fe2S2(CO)4(CN)2] precursor to the [2Fe] H component of the H-cluster, requiring only the completion of the bridging azadithiolate (SCH2NHCH2S) ligand. This model is built upon a foundation of data that incorporates cell-free synthesis, isotope sensitive spectroscopies, and the selective use of synthetic complexes substituting for intermediates in the enzymatic "assembly line". We discuss controversies pertaining to this model and some remaining open issues to be addressed by future work.
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Affiliation(s)
- R David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Lizhi Tao
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Guodong Rao
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Nanhao Chen
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Lee-Ping Wang
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
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14
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Nicolet Y, Cherrier MV, Amara P. Radical SAM Enzymes and Metallocofactor Assembly: A Structural Point of View. ACS BIO & MED CHEM AU 2022; 2:36-52. [PMID: 37102176 PMCID: PMC10114646 DOI: 10.1021/acsbiomedchemau.1c00044] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This Review focuses on the structure-function relationship of radical S-adenosyl-l-methionine (SAM) enzymes involved in the assembly of metallocofactors corresponding to the active sites of [FeFe]-hydrogenase and nitrogenase [MoFe]-protein. It does not claim to correspond to an extensive review on the assembly machineries of these enzyme active sites, for which many good reviews are already available, but instead deals with the contribution of structural data to the understanding of their chemical mechanism (Buren et al. Chem. Rev.2020, 142 ( (25), ) 11006-11012; Britt et al. Chem. Sci.2020, 11 ( (38), ), 10313-10323). Hence, we will present the history and current knowledge about the radical SAM maturases HydE, HydG, and NifB as well as what, in our opinion, should be done in the near future to overcome the existing barriers in our understanding of this fascinating chemistry that intertwine organic radicals and organometallic complexes.
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Affiliation(s)
- Yvain Nicolet
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| | - Mickael V. Cherrier
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| | - Patricia Amara
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
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15
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Zhang Y, Tao L, Woods TJ, Britt RD, Rauchfuss TB. Organometallic Fe 2(μ-SH) 2(CO) 4(CN) 2 Cluster Allows the Biosynthesis of the [FeFe]-Hydrogenase with Only the HydF Maturase. J Am Chem Soc 2022; 144:1534-1538. [PMID: 35041427 PMCID: PMC9169013 DOI: 10.1021/jacs.1c12506] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The biosynthesis of the active site of the [FeFe]-hydrogenases (HydA1), the H-cluster, is of interest because these enzymes are highly efficient catalysts for the oxidation and production of H2. The biosynthesis of the [2Fe]H subcluster of the H-cluster proceeds from simple precursors, which are processed by three maturases: HydG, HydE, and HydF. Previous studies established that HydG produces an Fe(CO)2(CN) adduct of cysteine, which is the substrate for HydE. In this work, we show that by using the synthetic cluster [Fe2(μ-SH)2(CN)2(CO)4]2- active HydA1 can be biosynthesized without maturases HydG and HydE.
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Affiliation(s)
- Yu Zhang
- School of Chemical Sciences, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Lizhi Tao
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Toby J Woods
- School of Chemical Sciences, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
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16
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Chen N, Rao G, Britt RD, Wang LP. Quantum Chemical Study of a Radical Relay Mechanism for the HydG-Catalyzed Synthesis of a Fe(II)(CO) 2(CN)cysteine Precursor to the H-Cluster of [FeFe] Hydrogenase. Biochemistry 2021; 60:3016-3026. [PMID: 34569243 DOI: 10.1021/acs.biochem.1c00379] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The [FeFe] hydrogenase catalyzes the redox interconversion of protons and H2 with a Fe-S "H-cluster" employing CO, CN, and azadithiolate ligands to two Fe centers. The biosynthesis of the H-cluster is a highly interesting reaction carried out by a set of Fe-S maturase enzymes called HydE, HydF, and HydG. HydG, a member of the radical S-adenosylmethionine (rSAM) family, converts tyrosine, cysteine, and Fe(II) into an organometallic Fe(II)(CO)2(CN)cysteine "synthon", which serves as the substrate for HydE. Although key aspects of the HydG mechanism have been experimentally determined via isotope-sensitive spectroscopic methods, other important mechanistic questions have eluded experimental determination. Here, we use computational quantum chemistry to refine the mechanism of the HydG catalytic reaction. We utilize quantum mechanics/molecular mechanics simulations to investigate the reactions at the canonical Fe-S cluster, where a radical cleavage of the tyrosine substrate takes place and proceeds through a relay of radical intermediates to form HCN and a COO•- radical anion. We then carry out a broken-symmetry density functional theory study of the reactions at the unusual five-iron auxiliary Fe-S cluster, where two equivalents of CN- and COOH• coordinate to the fifth "dangler iron" in a series of substitution and redox reactions that yield the synthon as the final product for further processing by HydE.
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Affiliation(s)
- Nanhao Chen
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Guodong Rao
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - R David Britt
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Lee-Ping Wang
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
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17
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Britt RD, Rauchfuss TB. Biosynthesis of the [FeFe] hydrogenase H-cluster via a synthetic [Fe(II)(CN)(CO) 2(cysteinate)] - complex. Dalton Trans 2021; 50:12386-12391. [PMID: 34545884 DOI: 10.1039/d1dt02258j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The H-cluster of [Fe-Fe] hydrogenase consists of a [4Fe]H subcluster linked by the sulfur of a cysteine residue to an organometallic [2Fe]H subcluster that utilizes terminal CO and CN ligands to each Fe along with a bridging CO and a bridging SCH2NHCH2S azadithiolate (adt) to catalyze proton reduction or hydrogen oxidation. Three Fe-S "maturase" proteins, HydE, HydF, and HydG, are responsible for the biosynthesis of the [2Fe]H subcluster and its incorporation into the hydrogenase enzyme to form this catalytically active H-cluster. We have proposed that HydG is a bifunctional enzyme that uses S-adenosylmethione (SAM) bound to a [4Fe-4S] cluster to lyse tyrosine via a transient 5'-deoxyadenosyl radical to produce CO and CN ligands to a unique cysteine-chelated Fe(II) that is linked to a second [4Fe-4S] cluster via the cysteine sulfur. In this "synthon model", after two cycles of tyrosine lysis, the product of HydG is completed: a [Fe(CN)(CO)2(cysteinate)]- organometallic unit that is vectored directly into the synthesis of the [2Fe]H sub-cluster. However our HydG-centric synthon model is not universally accepted, so further validation is important. In this Frontiers article, we discuss recent results using a synthetic "Syn-B" complex that donates [Fe(CN)(CO)2(cysteinate)]- units that match our proposed HydG product. Can Syn-B activate hydrogenase in the absence of HydG and its tyrosine substrate? If so, since Syn-B can be synthesized with specific magnetic nuclear isotopes and with chemical substitutions, its use could allow its enzymatic conversions on the route to the H-cluster to be monitored and modeled in fresh detail.
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Affiliation(s)
- R David Britt
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA.
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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18
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Shepard EM, Impano S, Duffus BR, Pagnier A, Duschene KS, Betz JN, Byer AS, Galambas A, McDaniel EC, Watts H, McGlynn SE, Peters JW, Broderick WE, Broderick JB. HydG, the "dangler" iron, and catalytic production of free CO and CN -: implications for [FeFe]-hydrogenase maturation. Dalton Trans 2021; 50:10405-10422. [PMID: 34240096 PMCID: PMC9154046 DOI: 10.1039/d1dt01359a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The organometallic H-cluster of the [FeFe]-hydrogenase consists of a [4Fe-4S] cubane bridged via a cysteinyl thiolate to a 2Fe subcluster ([2Fe]H) containing CO, CN-, and dithiomethylamine (DTMA) ligands. The H-cluster is synthesized by three dedicated maturation proteins: the radical SAM enzymes HydE and HydG synthesize the non-protein ligands, while the GTPase HydF serves as a scaffold for assembly of [2Fe]H prior to its delivery to the [FeFe]-hydrogenase containing the [4Fe-4S] cubane. HydG uses l-tyrosine as a substrate, cleaving it to produce p-cresol as well as the CO and CN- ligands to the H-cluster, although there is some question as to whether these are formed as free diatomics or as part of a [Fe(CO)2(CN)] synthon. Here we show that Clostridium acetobutylicum (C.a.) HydG catalyzes formation of multiple equivalents of free CO at rates comparable to those for CN- formation. Free CN- is also formed in excess molar equivalents over protein. A g = 8.9 EPR signal is observed for C.a. HydG reconstituted to load the 5th "dangler" iron of the auxiliary [4Fe-4S][FeCys] cluster and is assigned to this "dangler-loaded" cluster state. Free CO and CN- formation and the degree of activation of [FeFe]-hydrogenase all occur regardless of dangler loading, but are increased 10-35% in the dangler-loaded HydG; this indicates the dangler iron is not essential to this process but may affect relevant catalysis. During HydG turnover in the presence of myoglobin, the g = 8.9 signal remains unchanged, indicating that a [Fe(CO)2(CN)(Cys)] synthon is not formed at the dangler iron. Mutation of the only protein ligand to the dangler iron, H272, to alanine nearly completely abolishes both free CO formation and hydrogenase activation, however results show this is not due solely to the loss of the dangler iron. In experiments with wild type and H272A HydG, and with different degrees of dangler loading, we observe a consistent correlation between free CO/CN- formation and hydrogenase activation. Taken in full, our results point to free CO/CN-, but not an [Fe(CO)2(CN)(Cys)] synthon, as essential species in hydrogenase maturation.
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Affiliation(s)
- Eric M Shepard
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Stella Impano
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Benjamin R Duffus
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Adrien Pagnier
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Kaitlin S Duschene
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Jeremiah N Betz
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Amanda S Byer
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Amanda Galambas
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Elizabeth C McDaniel
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Hope Watts
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Shawn E McGlynn
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99163, USA
| | - William E Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Joan B Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT 59717, USA.
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19
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Rohac R, Martin L, Liu L, Basu D, Tao L, Britt RD, Rauchfuss TB, Nicolet Y. Crystal Structure of the [FeFe]-Hydrogenase Maturase HydE Bound to Complex-B. J Am Chem Soc 2021; 143:8499-8508. [PMID: 34048236 DOI: 10.1021/jacs.1c03367] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[FeFe]-hydrogenases use a unique organometallic complex, termed the H cluster, to reversibly convert H2 into protons and low-potential electrons. It can be best described as a [Fe4S4] cluster coupled to a unique [2Fe]H center where the reaction actually takes place. The latter corresponds to two iron atoms, each of which is bound by one CN- ligand and one CO ligand. The two iron atoms are connected by a unique azadithiolate molecule (-S-CH2-NH-CH2-S-) and an additional bridging CO. This [2Fe]H center is built stepwise thanks to the well-orchestrated action of maturating enzymes that belong to the Hyd machinery. Among them, HydG converts l-tyrosine into CO and CN- to produce a unique l-cysteine-Fe(CO)2CN species termed complex-B. Very recently, HydE was shown to perform radical-based chemistry using synthetic complex-B as a substrate. Here we report the high-resolution crystal structure that establishes the identity of the complex-B-bound HydE. By triggering the reaction prior to crystallization, we trapped a new five-coordinate Fe species, supporting the proposal that HydE performs complex modifications of complex-B to produce a monomeric "SFe(CO)2CN" precursor to the [2Fe]H center. Substrate access, product release, and intermediate transfer are also discussed.
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Affiliation(s)
- Roman Rohac
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| | - Lydie Martin
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| | - Liang Liu
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Debashis Basu
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Lizhi Tao
- Department of Chemistry, University of California-Davis, Davis, California 95616, United States
| | - R David Britt
- Department of Chemistry, University of California-Davis, Davis, California 95616, United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yvain Nicolet
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
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20
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Impano S, Yang H, Shepard EM, Swimley R, Pagnier A, Broderick WE, Hoffman BM, Broderick JB. S-Adenosyl-l-ethionine is a Catalytically Competent Analog of S-Adenosyl-l-methione (SAM) in the Radical SAM Enzyme HydG. Angew Chem Int Ed Engl 2021; 60:4666-4672. [PMID: 33935588 PMCID: PMC8081114 DOI: 10.1002/anie.202014337] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Indexed: 01/02/2023]
Abstract
Radical S-adenosyl-l-methionine (SAM) enzymes initiate biological radical reactions with the 5'-deoxyadenosyl radical (5'-dAdo•). A [4Fe-4S]+ cluster reductively cleaves SAM to form the Ω organometallic intermediate in which the 5'-deoxyadenosyl moiety is directly bound to the unique iron of the [4Fe-4S] cluster, with subsequent liberation of 5'-dAdo•. Here we present synthesis of the SAM analog S-adenosyl-l-ethionine (SAE) and show SAE is a mechanistically-equivalent SAM-alternative for HydG, both supporting enzymatic turnover of substrate tyrosine and forming the organometallic intermediate Ω. Photolysis of SAE bound to HydG forms an ethyl radical trapped in the active site. The ethyl radical withstands prolonged storage at 77 K and its EPR signal is only partially lost upon annealing at 100 K, making it significantly less reactive than the methyl radical formed by SAM photolysis. Upon annealing above 77K, the ethyl radical adds to the [4Fe-4S]2+ cluster, generating an ethyl-[4Fe-4S]3+ organometallic species termed ΩE.
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Affiliation(s)
- Stella Impano
- Department of Chemistry & Biochemistry, ontana State University, ozeman, MT. USA. 59717
| | - Hao Yang
- Department of Chemistry, Northwestern University, Evanston, IL. USA 60208
| | - Eric M Shepard
- Department of Chemistry & Biochemistry, ontana State University, ozeman, MT. USA. 59717
| | - Ryan Swimley
- Department of Chemistry & Biochemistry, ontana State University, ozeman, MT. USA. 59717
| | - Adrien Pagnier
- Department of Chemistry & Biochemistry, ontana State University, ozeman, MT. USA. 59717
| | - William E Broderick
- Department of Chemistry & Biochemistry, ontana State University, ozeman, MT. USA. 59717
| | - Brian M Hoffman
- Department of Chemistry & Biochemistry, ontana State University, ozeman, MT. USA. 59717
| | - Joan B Broderick
- Department of Chemistry & Biochemistry, ontana State University, ozeman, MT. USA. 59717
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21
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Impano S, Yang H, Shepard EM, Swimley R, Pagnier A, Broderick WE, Hoffman BM, Broderick JB. S
‐Adenosyl‐
l
‐ethionine is a Catalytically Competent Analog of
S
‐Adenosyl‐
l
‐methionine (SAM) in the Radical SAM Enzyme HydG. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Stella Impano
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Hao Yang
- Department of Chemistry Northwestern University Evanston IL 60208 USA
| | - Eric M. Shepard
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Ryan Swimley
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Adrien Pagnier
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - William E. Broderick
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
| | - Brian M. Hoffman
- Department of Chemistry Northwestern University Evanston IL 60208 USA
| | - Joan B. Broderick
- Department of Chemistry & Biochemistry Montana State University Bozeman MT 59717 USA
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22
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Kleinhaus JT, Wittkamp F, Yadav S, Siegmund D, Apfel UP. [FeFe]-Hydrogenases: maturation and reactivity of enzymatic systems and overview of biomimetic models. Chem Soc Rev 2021; 50:1668-1784. [DOI: 10.1039/d0cs01089h] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
[FeFe]-hydrogenases recieved increasing interest in the last decades. This review summarises important findings regarding their enzymatic reactivity as well as inorganic models applied as electro- and photochemical catalysts.
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Affiliation(s)
| | | | - Shanika Yadav
- Inorganic Chemistry I
- Ruhr University Bochum
- 44801 Bochum
- Germany
| | - Daniel Siegmund
- Department of Electrosynthesis
- Fraunhofer UMSICHT
- 46047 Oberhausen
- Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I
- Ruhr University Bochum
- 44801 Bochum
- Germany
- Department of Electrosynthesis
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23
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Britt RD, Rao G, Tao L. Biosynthesis of the catalytic H-cluster of [FeFe] hydrogenase: the roles of the Fe-S maturase proteins HydE, HydF, and HydG. Chem Sci 2020; 11:10313-10323. [PMID: 34123177 PMCID: PMC8162317 DOI: 10.1039/d0sc04216a] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/11/2020] [Indexed: 11/22/2022] Open
Abstract
[FeFe] hydrogenases carry out the redox interconversion of protons and molecular hydrogen (2H+ + 2e- ⇌ H2) at a complex Fe-S active site known as the H-cluster. The H-cluster consists of a [4Fe-4S] subcluster, denoted here as [4Fe]H, linked via a cysteine sulfur to an interesting organometallic [2Fe]H subcluster thought to be the subsite where the catalysis occurs. This [2Fe]H subcluster consists of two Fe atoms, linked with a bridging CO and a bridging SCH2NHCH2S azadithiolate (adt), with additional terminal CO and CN ligands bound to each Fe. Synthesizing such a complex organometallic unit is a fascinating problem in biochemistry, complicated by the toxic nature of both the CO and CN- species and the relative fragility of the azadithiolate bridge. It has been known for a number of years that this complex biosynthesis is carried out by a set of three essential Fe-S proteins, HydE, HydF, and HydG. HydF is a GTPase, while HydE and HydG are both members of the large family of radical S-adenosylmethionine (rSAM) enzymes. In this perspective we describe the history of research and discovery concerning these three Fe-S "maturase" proteins and describe recent evidence for a sequential biosynthetic pathway beginning with the synthesis of a mononuclear organometallic [Fe(ii)(CO)2CN(cysteine)] complex by the rSAM enzyme HydG and its subsequent activation by the second rSAM enzyme HydE to form a highly reactive Fe(i)(CO)2(CN)S species. In our model a pair of these Fe(i)(CO)2(CN)S units condense to form the [Fe(CO)2(CN)S]2 diamond core of the [2Fe]H cluster, requiring only the installation of the central CH2NHCH2 portion of the azadithiolate bridge, whose atoms are all sourced from the amino acid serine. This final step likely occurs with an interplay of HydE and HydF, the details of which yet remain to be elucidated.
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Affiliation(s)
- R David Britt
- Department of Chemistry, University of California, Davis Davis CA 95616 USA
| | - Guodong Rao
- Department of Chemistry, University of California, Davis Davis CA 95616 USA
| | - Lizhi Tao
- Department of Chemistry, University of California, Davis Davis CA 95616 USA
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24
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Németh B, Senger M, Redman HJ, Ceccaldi P, Broderick J, Magnuson A, Stripp ST, Haumann M, Berggren G. [FeFe]-hydrogenase maturation: H-cluster assembly intermediates tracked by electron paramagnetic resonance, infrared, and X-ray absorption spectroscopy. J Biol Inorg Chem 2020; 25:777-788. [PMID: 32661785 PMCID: PMC7399679 DOI: 10.1007/s00775-020-01799-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/09/2020] [Indexed: 11/25/2022]
Abstract
[FeFe]-hydrogenase enzymes employ a unique organometallic cofactor for efficient and reversible hydrogen conversion. This so-called H-cluster consists of a [4Fe-4S] cubane cysteine linked to a diiron complex coordinated by carbon monoxide and cyanide ligands and an azadithiolate ligand (adt = NH(CH2S)2)·[FeFe]-hydrogenase apo-protein binding only the [4Fe-4S] sub-complex can be fully activated in vitro by the addition of a synthetic diiron site precursor complex ([2Fe]adt). Elucidation of the mechanism of cofactor assembly will aid in the design of improved hydrogen processing synthetic catalysts. We combined electron paramagnetic resonance, Fourier-transform infrared, and X-ray absorption spectroscopy to characterize intermediates of H-cluster assembly as initiated by mixing of the apo-protein (HydA1) from the green alga Chlamydomonas reinhardtii with [2Fe]adt. The three methods consistently show rapid formation of a complete H-cluster in the oxidized, CO-inhibited state (Hox-CO) already within seconds after the mixing. Moreover, FTIR spectroscopy support a model in which Hox-CO formation is preceded by a short-lived Hred'-CO-like intermediate. Accumulation of Hox-CO was followed by CO release resulting in the slower conversion to the catalytically active state (Hox) as well as formation of reduced states of the H-cluster.
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Affiliation(s)
- Brigitta Németh
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Moritz Senger
- Physics Department, Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
- Department of Chemistry, Ångström Laboratory, Physical Chemistry, Uppsala University, 75120, Uppsala, Sweden
| | - Holly J Redman
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Pierre Ceccaldi
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Joan Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Ann Magnuson
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Sven T Stripp
- Physics Department, Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
| | - Michael Haumann
- Physics Department, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195, Berlin, Germany
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden.
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25
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Sayler R, Stich TA, Joshi S, Cooper N, Shaw JT, Begley TP, Tantillo DJ, Britt RD. Trapping and Electron Paramagnetic Resonance Characterization of the 5'dAdo • Radical in a Radical S-Adenosyl Methionine Enzyme Reaction with a Non-Native Substrate. ACS CENTRAL SCIENCE 2019; 5:1777-1785. [PMID: 31807679 PMCID: PMC6891858 DOI: 10.1021/acscentsci.9b00706] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Indexed: 05/03/2023]
Abstract
S-Adenosyl methionine (SAM) is employed as a [4Fe-4S]-bound cofactor in the superfamily of radical SAM (rSAM) enzymes, in which one-electron reduction of the [4Fe-4S]-SAM moiety leads to homolytic cleavage of the S-adenosyl methionine to generate the 5'-deoxyadenosyl radical (5'dAdo•), a potent H-atom abstractor. HydG, a member of this rSAM family, uses the 5'dAdo• radical to lyse its substrate, tyrosine, producing CO and CN that bind to a unique Fe site of a second HydG Fe-S cluster, ultimately producing a mononuclear organometallic Fe-l-cysteine-(CO)2CN complex as an intermediate in the bioassembly of the catalytic H-cluster of [Fe-Fe] hydrogenase. Here we report the use of non-native tyrosine substrate analogues to further probe the initial radical chemistry of HydG. One such non-native substrate is 4-hydroxy phenyl propanoic acid (HPPA) which lacks the amino group of tyrosine, replacing the CαH-NH2 with a CH2 at the C2 position. Electron paramagnetic resonance (EPR) studies show the generation of a strong and relatively stable radical in the HydG reaction with natural abundance and 13C2-HPPA, with appreciable spin density localized at C2. These results led us to try parallel experiments with the more oxidized non-native substrate coumaric acid, which has a C2=C3 alkene substitution relative to HPPA's single bond. Interestingly, the HydG reaction with the cis-p-coumaric acid isomer led to the trapping of a new radical EPR signal, and EPR studies using cis-p-coumaric acid along with isotopically labeled SAM reveal that we have for the first time trapped and characterized the 5'dAdo• radical in an actual rSAM enzyme reaction, here by using this specific non-native substrate cis-p-coumaric acid. Density functional theory energetics calculations show that the cis-p-coumaric acid has approximately the same C-H bond dissociation free energy as 5'dAdo•, providing a possible explanation for our ability to trap an appreciable fraction of 5'dAdo• in this specific rSAM reaction. The radical's EPR line shape and its changes with SAM isotopic substitution are nearly identical to those of a 5'dAdo• radical recently generated by cryophotolysis of a prereduced [4Fe-4S]-SAM center in another rSAM enzyme, pyruvate formate-lyase activating enzyme, further supporting our assignment that we have indeed trapped and characterized the 5'dAdo• radical in a radical SAM enzymatic reaction by appropriate tuning of the relative radical free energies via the judicious selection of a non-native substrate.
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Affiliation(s)
- Richard
I. Sayler
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Troy A. Stich
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Sumedh Joshi
- Department
of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Nicole Cooper
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Jared T. Shaw
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Tadhg P. Begley
- Department
of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Dean J. Tantillo
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - R. David Britt
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
- E-mail: . Phone: (530) 752
6377
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26
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Yang H, Impano S, Shepard EM, James CD, Broderick WE, Broderick JB, Hoffman BM. Photoinduced Electron Transfer in a Radical SAM Enzyme Generates an S-Adenosylmethionine Derived Methyl Radical. J Am Chem Soc 2019; 141:16117-16124. [PMID: 31509404 DOI: 10.1021/jacs.9b08541] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Radical SAM (RS) enzymes use S-adenosyl-l-methionine (SAM) and a [4Fe-4S] cluster to initiate a broad spectrum of radical transformations throughout all kingdoms of life. We report here that low-temperature photoinduced electron transfer from the [4Fe-4S]1+ cluster to bound SAM in the active site of the hydrogenase maturase RS enzyme, HydG, results in specific homolytic cleavage of the S-CH3 bond of SAM, rather than the S-C5' bond as in the enzyme-catalyzed (thermal) HydG reaction. This result is in stark contrast to a recent report in which photoinduced ET in the RS enzyme pyruvate formate-lyase activating enzyme cleaved the S-C5' bond to generate a 5'-deoxyadenosyl radical, and provides the first direct evidence for homolytic S-CH3 bond cleavage in a RS enzyme. Photoinduced ET in HydG generates a trapped •CH3 radical, as well as a small population of an organometallic species with an Fe-CH3 bond, denoted ΩM. The •CH3 radical is surprisingly found to exhibit rotational diffusion in the HydG active site at temperatures as low as 40 K, and is rapidly quenched: whereas 5'-dAdo• is stable indefinitely at 77 K, •CH3 quenches with a half-time of ∼2 min at this temperature. The rapid quenching and rotational/translational freedom of •CH3 shows that enzymes would be unable to harness this radical as a regio- and stereospecific H atom abstractor during catalysis, in contrast to the exquisite control achieved with the enzymatically generated 5'-dAdo•.
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Affiliation(s)
- Hao Yang
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Stella Impano
- Department of Chemistry & Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Eric M Shepard
- Department of Chemistry & Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Christopher D James
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - William E Broderick
- Department of Chemistry & Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Joan B Broderick
- Department of Chemistry & Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Brian M Hoffman
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
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27
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H-cluster assembly intermediates built on HydF by the radical SAM enzymes HydE and HydG. J Biol Inorg Chem 2019; 24:783-792. [PMID: 31493152 DOI: 10.1007/s00775-019-01709-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/13/2019] [Indexed: 12/12/2022]
Abstract
[FeFe]-hydrogenase catalyzes the reversible reduction of protons to H2 at a complex metallocofactor site, the H-cluster. Biosynthesis of this active-site H-cluster requires three maturation enzymes: the radical S-adenosylmethionine enzymes HydE and HydG synthesize the nonprotein ligands, while the GTPase HydF provides a scaffold for assembly of the 2Fe subcluster of the H-cluster ([2Fe]H) prior to its transfer to hydrogenase. To delineate the assembly and delivery steps for the 2Fe precursor cluster coordinated to HydF ([2Fe]F), we have heterologously expressed HydF in the presence of HydE alone (HydFE) or HydG alone (HydFG), and characterized the resulting purified HydFE and HydFG using UV-visible, EPR, and FTIR spectroscopies and biochemical assays. The iron-sulfur clusters on HydF are modified by co-expression with HydE or HydG, as evidenced by the changes in the visible, EPR, and FTIR spectral features. Further, biochemical assays show that HydFE is capable of activating HydAΔEFG to a limited extent (~ 1% of WT) even though the normal source of CO and CN- ligands of [2Fe]H (HydG) was absent. Activation assays performed with HydFG, in contrast, exhibit no ability to mature HydAΔEFG. It appears that in the case of HydFE, trace diatomics from the cellular environment are incorporated into a [2Fe]F-like precursor on HydF in the absence of HydG. We conclude that the product of HydE, presumably the dithiomethylamine ligand of [2Fe]H, is absolutely essential to the activation process, while the diatomic products of HydG can be provided from alternate sources.
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28
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Honarmand Ebrahimi K. A unifying view of the broad-spectrum antiviral activity of RSAD2 (viperin) based on its radical-SAM chemistry. Metallomics 2019; 10:539-552. [PMID: 29568838 DOI: 10.1039/c7mt00341b] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
RSAD2 (cig-5), also known as viperin (virus inhibitory protein, endoplasmic reticulum associated, interferon inducible), is a member of the radical S-adenosylmethionine (SAM) superfamily of enzymes. Since the discovery of this enzyme more than a decade ago, numerous studies have shown that it exhibits antiviral activity against a wide range of viruses. However, there is no clear picture demonstrating the mechanism by which RSAD2 restricts the replication process of different viruses, largely because there is no direct evidence describing its in vivo enzymatic activity. As a result, a multifunctionality model has emerged. According to this model the mechanism by which RSAD2 restricts replication of different viruses varies and in many cases is not dependent on the radical-SAM chemistry of RSAD2. If the radical-SAM activity of RSAD2 is not required for its antiviral function, the question worth asking is: why does the cellular defence mechanism induce the expression of the radical-SAM enzyme RSAD2, which is metabolically expensive due to the requirement for a [4Fe-4S] cluster and usage of SAM? Here, in contrast to the multifunctionality view, I put forward a unifying model. I postulate that the radical-SAM activity of RSAD2 modulates cellular metabolic pathways essential for viral replication and/or cell proliferation and survival. As a result, its catalytic activity restricts the replication of a wide range of viruses via a common cellular function. This view is based on recent discoveries hinting towards possible substrates of RSAD2, re-evaluation of previous studies regarding the antiviral activity of RSAD2, and accumulating evidence suggesting a role of human RSAD2 in the metabolic reprogramming of cells.
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29
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Németh B, Esmieu C, Redman HJ, Berggren G. Monitoring H-cluster assembly using a semi-synthetic HydF protein. Dalton Trans 2019; 48:5978-5986. [PMID: 30632592 PMCID: PMC6509880 DOI: 10.1039/c8dt04294b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/21/2018] [Indexed: 11/21/2022]
Abstract
The [FeFe] hydrogenase enzyme interconverts protons and molecular hydrogen with remarkable efficiency. The reaction is catalysed by a unique metallo-cofactor denoted as the H-cluster containing an organometallic dinuclear Fe component, the [2Fe] subsite. The HydF protein delivers a precursor of the [2Fe] subsite to the apo-[FeFe] hydrogenase, thus completing the H-cluster and activating the enzyme. Herein we generate a semi-synthetic form of HydF by loading it with a synthetic low valent dinuclear Fe complex. We show that this semi-synthetic protein is practically indistinguishable from the native protein, and utilize this form of HydF to explore the mechanism of H-cluster assembly. More specifically, we show that transfer of the precatalyst from HydF to the hydrogenase enzyme results in the release of CO, underscoring that the pre-catalyst is a four CO species when bound to HydF. Moreover, we propose that an electron transfer reaction occurs during H-cluster assembly, resulting in an oxidation of the [2Fe] subsite with concomitant reduction of the [4Fe4S] cluster present on the HydF protein.
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Affiliation(s)
- Brigitta Németh
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
| | - Charlène Esmieu
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
| | - Holly J. Redman
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
| | - Gustav Berggren
- Molecular Biomimetics
, Department of Chemistry – Ångström Laboratory
, Uppsala University
,
75120 Uppsala
, Sweden
.
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30
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31
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Broderick WE, Hoffman BM, Broderick JB. Mechanism of Radical Initiation in the Radical S-Adenosyl-l-methionine Superfamily. Acc Chem Res 2018; 51:2611-2619. [PMID: 30346729 PMCID: PMC6324848 DOI: 10.1021/acs.accounts.8b00356] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The seeds for recognition of the vast superfamily of radical S-adenosyl-l-methionine (SAM) enzymes were sown in the 1960s, when Joachim Knappe found that the dissimilation of pyruvate was dependent on SAM and Fe(II), and Barker and co-workers made similar observations for lysine 2,3-aminomutase. These intriguing observations, coupled with the evidence that SAM and Fe were cofactors in radical catalysis by these enzyme systems, drew us in the 1990s to explore how Fe(II) and SAM initiate radical reactions. Our early work focused on the same enzyme Knappe had originally characterized: the pyruvate formate-lyase activating enzyme (PFL-AE). Our discovery of an iron-sulfur cluster in this enzyme, together with similar findings for other SAM-dependent enzymes at the time, led to the recognition of an emerging class of enzymes that use iron-sulfur clusters to cleave SAM, liberating the 5'-deoxyadenosyl radical (5'-dAdo•) that initiates radical reactions. A major bioinformatics study by Heidi Sofia and co-workers identified the enzyme superfamily denoted Radical SAM, now known to span all kingdoms of life with more than 100,000 unique sequences encoding enzymes that catalyze remarkably diverse reactions. Despite the limited sequence similarity and vastly divergent reactions catalyzed, the radical SAM enzymes appear to employ a common mechanism for initiation of radical chemistry, a mechanism we have helped to clarify over the last 25 years. A reduced [4Fe-4S]+ cluster provides the electron needed for the reductive cleavage of SAM. The resulting [4Fe-4S]2+ cluster can be rereduced either by an external reductant, with SAM acting as a cosubstrate, or by an electron provided during the reformation of SAM in cases where SAM is used as a cofactor. The amino and carboxylate groups of SAM bind to the unique iron of the catalytic [4Fe-4S] cluster, placing the sulfonium of SAM in close proximity to the cluster. Surprising recent results have shown that the initiating enzymatic cleavage of SAM generates an organometallic intermediate prior to liberation of 5'-dAdo•, which initiates radical chemistry on the substrate. This organometallic intermediate, denoted Ω, has a 5'-deoxyadenosyl moiety directly bound to the unique iron of the [4Fe-4S] cluster via the 5'-C, giving a structure that is directly analogous to the Co-(5'-C) bond of the organometallic cofactor adenosylcobalamin. Our observation that this intermediate Ω is formed throughout the superfamily suggests that this is a key intermediate in initiating radical SAM reactions, and that organometallic chemistry is much more broadly relevant in biology than previously thought.
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Affiliation(s)
- William E. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Brian M. Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Joan B. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States,Corresponding Author, .
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32
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Amara P, Mouesca JM, Bella M, Martin L, Saragaglia C, Gambarelli S, Nicolet Y. Radical S-Adenosyl-l-methionine Tryptophan Lyase (NosL): How the Protein Controls the Carboxyl Radical •CO 2- Migration. J Am Chem Soc 2018; 140:16661-16668. [PMID: 30418774 DOI: 10.1021/jacs.8b09142] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The radical S-adenosyl-l-methionine tryptophan lyase uses radical-based chemistry to convert l-tryptophan into 3-methyl-2-indolic acid, a fragment in the biosynthesis of the thiopeptide antibiotic nosiheptide. This complex reaction involves several successive steps corresponding to (i) the activation by a specific hydrogen-atom abstraction, (ii) an unprecedented •CO2- radical migration, (iii) a cyanide fragment release, and (iv) the termination of the radical-based reaction. In vitro study of this reaction is made more difficult because the enzyme produces a significant amount of a shunt product instead of the natural product. Here, using a combination of X-ray crystallography, electron paramagnetic resonance spectroscopy, and quantum and hybrid quantum mechanical/molecular mechanical calculations, we have deciphered the fine mechanism of the key •CO2- radical migration, highlighting how the preorganized active site of the protein tightly controls this reaction.
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Affiliation(s)
- Patricia Amara
- Univ. Grenoble Alpes, CEA, CNRS, IBS , Metalloproteins Unit , F-38000 Grenoble , France
| | | | - Maxime Bella
- Univ. Grenoble Alpes, CEA, CNRS, IBS , Metalloproteins Unit , F-38000 Grenoble , France
| | - Lydie Martin
- Univ. Grenoble Alpes, CEA, CNRS, IBS , Metalloproteins Unit , F-38000 Grenoble , France
| | - Claire Saragaglia
- Univ. Grenoble Alpes, CEA, CNRS, IBS , Metalloproteins Unit , F-38000 Grenoble , France
| | - Serge Gambarelli
- Univ. Grenoble Alpes, CNRS, CEA , INAC-SyMMES , 38000 Grenoble , France
| | - Yvain Nicolet
- Univ. Grenoble Alpes, CEA, CNRS, IBS , Metalloproteins Unit , F-38000 Grenoble , France
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33
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Byer A, Yang H, McDaniel EC, Kathiresan V, Impano S, Pagnier A, Watts H, Denler C, Vagstad AL, Piel J, Duschene KS, Shepard EM, Shields TP, Scott LG, Lilla EA, Yokoyama K, Broderick WE, Hoffman BM, Broderick JB. Paradigm Shift for Radical S-Adenosyl-l-methionine Reactions: The Organometallic Intermediate Ω Is Central to Catalysis. J Am Chem Soc 2018; 140:8634-8638. [PMID: 29954180 PMCID: PMC6053644 DOI: 10.1021/jacs.8b04061] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Radical S-adenosyl-l-methionine (SAM) enzymes comprise a vast superfamily catalyzing diverse reactions essential to all life through homolytic SAM cleavage to liberate the highly reactive 5'-deoxyadenosyl radical (5'-dAdo·). Our recent observation of a catalytically competent organometallic intermediate Ω that forms during reaction of the radical SAM (RS) enzyme pyruvate formate-lyase activating-enzyme (PFL-AE) was therefore quite surprising, and led to the question of its broad relevance in the superfamily. We now show that Ω in PFL-AE forms as an intermediate under a variety of mixing order conditions, suggesting it is central to catalysis in this enzyme. We further demonstrate that Ω forms in a suite of RS enzymes chosen to span the totality of superfamily reaction types, implicating Ω as essential in catalysis across the RS superfamily. Finally, EPR and electron nuclear double resonance spectroscopy establish that Ω involves an Fe-C5' bond between 5'-dAdo· and the [4Fe-4S] cluster. An analogous organometallic bond is found in the well-known adenosylcobalamin (coenzyme B12) cofactor used to initiate radical reactions via a 5'-dAdo· intermediate. Liberation of a reactive 5'-dAdo· intermediate via homolytic metal-carbon bond cleavage thus appears to be similar for Ω and coenzyme B12. However, coenzyme B12 is involved in enzymes catalyzing only a small number (∼12) of distinct reactions, whereas the RS superfamily has more than 100 000 distinct sequences and over 80 reaction types characterized to date. The appearance of Ω across the RS superfamily therefore dramatically enlarges the sphere of bio-organometallic chemistry in Nature.
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Affiliation(s)
- Amanda
S. Byer
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Hao Yang
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Elizabeth C. McDaniel
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Venkatesan Kathiresan
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Stella Impano
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Adrien Pagnier
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Hope Watts
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Carly Denler
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Anna L. Vagstad
- Institute
of Microbiology, Eidgenössische Technische
Hochschule Zürich, Vladimir-Prelog-Weg 4, Zürich 8093, Switzerland
| | - Jörn Piel
- Institute
of Microbiology, Eidgenössische Technische
Hochschule Zürich, Vladimir-Prelog-Weg 4, Zürich 8093, Switzerland
| | - Kaitlin S. Duschene
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Eric M. Shepard
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Thomas P. Shields
- Cassia,
LLC, 3030 Bunker Hill
Street, Ste. 214, San Diego, California 92109, United States
| | - Lincoln G. Scott
- Cassia,
LLC, 3030 Bunker Hill
Street, Ste. 214, San Diego, California 92109, United States
| | - Edward A. Lilla
- Department
of Biochemistry, Duke University Medical
Center, Durham, North Carolina 27710, United States
| | - Kenichi Yokoyama
- Department
of Biochemistry, Duke University Medical
Center, Durham, North Carolina 27710, United States
| | - William E. Broderick
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States
| | - Brian M. Hoffman
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States,
| | - Joan B. Broderick
- Department
of Chemistry & Biochemistry, Montana
State University, Bozeman, Montana 59717, United States,
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34
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Scott AG, Szilagyi RK, Mulder DW, Ratzloff MW, Byer AS, King PW, Broderick WE, Shepard EM, Broderick JB. Compositional and structural insights into the nature of the H-cluster precursor on HydF. Dalton Trans 2018; 47:9521-9535. [PMID: 29964288 DOI: 10.1039/c8dt01654b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Assembly of an active [FeFe]-hydrogenase requires dedicated maturation enzymes that generate the active-site H-cluster: the radical SAM enzymes HydE and HydG synthesize the unusual non-protein ligands - carbon monoxide, cyanide, and dithiomethylamine - while the GTPase HydF serves as a scaffold for assembly of the 2Fe subcluster containing these ligands. In the current study, enzymatically cluster-loaded HydF ([2Fe]F) is produced by co-expression with HydE and HydG in an Escherichia coli host followed by isolation and examination by FTIR and EPR spectroscopy. FTIR reveals the presence of well-defined terminal CO and CN- ligands; however, unlike in the [FeFe]-hydrogenase, no bridging CO is observed. Exposure of this loaded HydF to exogenous CO or H2 produces no significant changes to the FTIR spectrum, indicating that, unlike in the [FeFe]-hydrogenase, the 2Fe cluster in loaded HydF is coordinatively saturated and relatively unreactive. EPR spectroscopy reveals the presence of both [4Fe-4S] and [2Fe-2S] clusters on this loaded HydF, but provides no direct evidence for these being linked to the [2Fe]F. Using the chemical reactivity and FTIR data, a large collection of computational models were evaluated. Their scaled quantum chemical vibrational spectra allowed us to score various [2Fe]F structures in terms of their ability to reproduce the diatomic stretching frequencies observed in the FTIR experimental spectra. Collectively, the results provide new insights that support the presence of a diamagnetic, but spin-polarized FeI-FeI oxidation state for the [2Fe]F precursor cluster that is coordinated by 4 CO and 2 CN- ligands, and bridged to an adjacent iron-sulfur cluster through one of the CN- ligands.
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Affiliation(s)
- Anna G Scott
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA.
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35
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Yokoyama K, Lilla EA. C-C bond forming radical SAM enzymes involved in the construction of carbon skeletons of cofactors and natural products. Nat Prod Rep 2018; 35:660-694. [PMID: 29633774 PMCID: PMC6051890 DOI: 10.1039/c8np00006a] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to the end of 2017 C-C bond formations are frequently the key steps in cofactor and natural product biosynthesis. Historically, C-C bond formations were thought to proceed by two electron mechanisms, represented by Claisen condensation in fatty acids and polyketide biosynthesis. These types of mechanisms require activated substrates to create a nucleophile and an electrophile. More recently, increasing number of C-C bond formations catalyzed by radical SAM enzymes are being identified. These free radical mediated reactions can proceed between almost any sp3 and sp2 carbon centers, allowing introduction of C-C bonds at unconventional positions in metabolites. Therefore, free radical mediated C-C bond formations are frequently found in the construction of structurally unique and complex metabolites. This review discusses our current understanding of the functions and mechanisms of C-C bond forming radical SAM enzymes and highlights their important roles in the biosynthesis of structurally complex, naturally occurring organic molecules. Mechanistic consideration of C-C bond formation by radical SAM enzymes identifies the significance of three key mechanistic factors: radical initiation, acceptor substrate activation and radical quenching. Understanding the functions and mechanisms of these characteristic enzymes will be important not only in promoting our understanding of radical SAM enzymes, but also for understanding natural product and cofactor biosynthesis.
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Affiliation(s)
- Kenichi Yokoyama
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
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36
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A [4Fe-4S]-Fe(CO)(CN)-L-cysteine intermediate is the first organometallic precursor in [FeFe] hydrogenase H-cluster bioassembly. Nat Chem 2018; 10:555-560. [PMID: 29632334 PMCID: PMC6380689 DOI: 10.1038/s41557-018-0026-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/14/2018] [Indexed: 12/27/2022]
Abstract
Biosynthesis of the [FeFe] hydrogenase active site (the 'H-cluster') requires the interplay of multiple proteins and small molecules. Among them, the radical S-adenosylmethionine enzyme HydG, a tyrosine lyase, has been proposed to generate a complex that contains an Fe(CO)2(CN) moiety that is eventually incorporated into the H-cluster. Here we describe the characterization of an intermediate in the HydG reaction: a [4Fe-4S][(Cys)Fe(CO)(CN)] species, 'Complex A', in which a CO, a CN- and a cysteine (Cys) molecule bind to the unique 'dangler' Fe site of the auxiliary [5Fe-4S] cluster of HydG. The identification of this intermediate-the first organometallic precursor to the H-cluster-validates the previously hypothesized HydG reaction cycle and provides a basis for elucidating the biosynthetic origin of other moieties of the H-cluster.
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Bhandari DM, Fedoseyenko D, Begley TP. Mechanistic Studies on Tryptophan Lyase (NosL): Identification of Cyanide as a Reaction Product. J Am Chem Soc 2018; 140:542-545. [PMID: 29232124 PMCID: PMC6078386 DOI: 10.1021/jacs.7b09000] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tryptophan lyase (NosL) catalyzes the formation of 3-methylindole-2-carboxylic acid and 3-methylindole from l-tryptophan. In this paper, we provide evidence supporting a formate radical intermediate and demonstrate that cyanide is a byproduct of the NosL-catalyzed reaction with l-tryptophan. These experiments require a major revision of the NosL mechanism and uncover an unanticipated connection between NosL and HydG, the radical SAM enzyme that forms cyanide and carbon monoxide from tyrosine during the biosynthesis of the metallo-cluster of the [Fe-Fe] hydrogenase.
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Affiliation(s)
- Dhananjay M. Bhandari
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Dmytro Fedoseyenko
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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Bhandari DM, Fedoseyenko D, Begley TP. Mechanistic Studies on the Radical SAM Enzyme Tryptophan Lyase (NosL). Methods Enzymol 2018; 606:155-178. [DOI: 10.1016/bs.mie.2018.06.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Martinez JL, Lin HJ, Lee WT, Pink M, Chen CH, Gao X, Dickie DA, Smith JM. Cyanide Ligand Assembly by Carbon Atom Transfer to an Iron Nitride. J Am Chem Soc 2017; 139:14037-14040. [PMID: 28933864 DOI: 10.1021/jacs.7b08704] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The new iron(IV) nitride complex PhB(iPr2Im)3Fe≡N reacts with 2 equiv of bis(diisopropylamino)cyclopropenylidene (BAC) to provide PhB(iPr2Im)3Fe(CN)(N2)(BAC). This unusual example of a four-electron reaction involves carbon atom transfer from BAC to create a cyanide ligand along with the alkyne iPr2N-C≡C-NiPr2. The iron complex is in equilibrium with an N2-free species. Further reaction with CO leads to formation of a CO analogue, which can be independently prepared using NaCN as the cyanide source, while reaction with B(C6F5)3 provides the cyanoborane derivative.
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Affiliation(s)
- Jorge L Martinez
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Hsiu-Jung Lin
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Wei-Tsung Lee
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Maren Pink
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Chun-Hsing Chen
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Xinfeng Gao
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Diane A Dickie
- Department of Chemistry and Chemical Biology, University of New Mexico , Albuquerque, New Mexico 87131, United States
| | - Jeremy M Smith
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Shepard EM, Byer AS, Aggarwal P, Betz JN, Scott AG, Shisler KA, Usselman RJ, Eaton GR, Eaton SS, Broderick JB. Electron Spin Relaxation and Biochemical Characterization of the Hydrogenase Maturase HydF: Insights into [2Fe-2S] and [4Fe-4S] Cluster Communication and Hydrogenase Activation. Biochemistry 2017; 56:3234-3247. [PMID: 28525271 PMCID: PMC5490485 DOI: 10.1021/acs.biochem.7b00169] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nature utilizes [FeFe]-hydrogenase enzymes to catalyze the interconversion between H2 and protons and electrons. Catalysis occurs at the H-cluster, a carbon monoxide-, cyanide-, and dithiomethylamine-coordinated 2Fe subcluster bridged via a cysteine to a [4Fe-4S] cluster. Biosynthesis of this unique metallocofactor is accomplished by three maturase enzymes denoted HydE, HydF, and HydG. HydE and HydG belong to the radical S-adenosylmethionine superfamily of enzymes and synthesize the nonprotein ligands of the H-cluster. These enzymes interact with HydF, a GTPase that acts as a scaffold or carrier protein during 2Fe subcluster assembly. Prior characterization of HydF demonstrated the protein exists in both dimeric and tetrameric states and coordinates both [4Fe-4S]2+/+ and [2Fe-2S]2+/+ clusters [Shepard, E. M., Byer, A. S., Betz, J. N., Peters, J. W., and Broderick, J. B. (2016) Biochemistry 55, 3514-3527]. Herein, electron paramagnetic resonance (EPR) is utilized to characterize the [2Fe-2S]+ and [4Fe-4S]+ clusters bound to HydF. Examination of spin relaxation times using pulsed EPR in HydF samples exhibiting both [4Fe-4S]+ and [2Fe-2S]+ cluster EPR signals supports a model in which the two cluster types either are bound to widely separated sites on HydF or are not simultaneously bound to a single HydF species. Gel filtration chromatographic analyses of HydF spectroscopic samples strongly suggest the [2Fe-2S]+ and [4Fe-4S]+ clusters are coordinated to the dimeric form of the protein. Lastly, we examined the 2Fe subcluster-loaded form of HydF and showed the dimeric state is responsible for [FeFe]-hydrogenase activation. Together, the results indicate a specific role for the HydF dimer in the H-cluster biosynthesis pathway.
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Affiliation(s)
- Eric M Shepard
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Amanda S Byer
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Priyanka Aggarwal
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Jeremiah N Betz
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Anna G Scott
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Krista A Shisler
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Robert J Usselman
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Joan B Broderick
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
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Sulfatases and radical SAM enzymes: emerging themes in glycosaminoglycan metabolism and the human microbiota. Biochem Soc Trans 2016; 44:109-15. [PMID: 26862195 DOI: 10.1042/bst20150191] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Humans live in a permanent association with bacterial populations collectively called the microbiota. In the last 10 years, major advances in our knowledge of the microbiota have shed light on its critical roles in human physiology. The microbiota has also been shown to be a major factor in numerous pathologies including obesity or inflammatory disorders. Despite tremendous progresses, our understanding of the key functions of the human microbiota and the molecular basis of its interactions with the host remain still poorly understood. Among the factors involved in host colonization, two enzymes families, sulfatases and radical S-adenosyl-L-methionine enzymes, have recently emerged as key enzymes.
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Hunt A, Barrett J, McCurry M, Works C. Photochemical reactivity of a binuclear Fe(I)–Fe(I) hydrogenase model compound with cyano ligands. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dinis P, Wieckowski BM, Roach PL. Metallocofactor assembly for [FeFe]-hydrogenases. Curr Opin Struct Biol 2016; 41:90-97. [PMID: 27344601 DOI: 10.1016/j.sbi.2016.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 06/05/2016] [Accepted: 06/06/2016] [Indexed: 11/27/2022]
Abstract
Hydrogenases are a potential source of environmentally benign bioenergy, using complex cofactors to catalyze the reversible reduction of protons to form hydrogen. The most active subclass, the [FeFe]-hydrogenases, is dependent on a metallocofactor, the H cluster, that consists of a two iron subcluster ([2Fe]H) bridging to a classical cubane cluster ([4Fe-4S]H). The ligands coordinating to the diiron subcluster include an azadithiolate, three carbon monoxides, and two cyanides. To assemble this complex cofactor, three maturase enzymes, HydG, HydE and HydF are required. The biosynthesis of the diatomic ligands proceeds by an unusual fragmentation mechanism, and structural studies in combination with spectroscopic analysis have started to provide insights into the HydG mediated assembly of a [2Fe]H subcluster precursor.
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Affiliation(s)
- Pedro Dinis
- Chemistry and the Institute for Life Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Beata M Wieckowski
- Chemistry and the Institute for Life Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Peter L Roach
- Chemistry and the Institute for Life Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK.
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Shepard EM, Byer AS, Betz JN, Peters JW, Broderick JB. A Redox Active [2Fe-2S] Cluster on the Hydrogenase Maturase HydF. Biochemistry 2016; 55:3514-27. [PMID: 27232385 DOI: 10.1021/acs.biochem.6b00528] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
[FeFe]-hydrogenases are nature's most prolific hydrogen catalysts, excelling at facilely interconverting H2 and protons. The catalytic core common to all [FeFe]-hydrogenases is a complex metallocofactor, referred to as the H-cluster, which is composed of a standard [4Fe-4S] cluster linked through a bridging thiolate to a 2Fe subcluster harboring dithiomethylamine, carbon monoxide, and cyanide ligands. This 2Fe subcluster is synthesized and inserted into [FeFe]-hydrogenase by three maturase enzymes denoted HydE, HydF, and HydG. HydE and HydG are radical S-adenosylmethionine enzymes and synthesize the nonprotein ligands of the H-cluster. HydF is a GTPase that functions as a scaffold or carrier for 2Fe subcluster production. Herein, we utilize UV-visible, circular dichroism, and electron paramagnetic resonance spectroscopic studies to establish the existence of redox active [4Fe-4S] and [2Fe-2S] clusters bound to HydF. We have used spectroelectrochemical titrations to assign iron-sulfur cluster midpoint potentials, have shown that HydF purifies with a reduced [2Fe-2S] cluster in the absence of exogenous reducing agents, and have tracked iron-sulfur cluster spectroscopic changes with quaternary structural perturbations. Our results provide an important foundation for understanding the maturation process by defining the iron-sulfur cluster content of HydF prior to its interaction with HydE and HydG. We speculate that the [2Fe-2S] cluster of HydF either acts as a placeholder for HydG-derived Fe(CO)2CN species or serves as a scaffold for 2Fe subcluster assembly.
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Affiliation(s)
- Eric M Shepard
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Amanda S Byer
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Jeremiah N Betz
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - John W Peters
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Joan B Broderick
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
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Suess DLM, Pham CC, Bürstel I, Swartz JR, Cramer SP, Britt RD. The Radical SAM Enzyme HydG Requires Cysteine and a Dangler Iron for Generating an Organometallic Precursor to the [FeFe]-Hydrogenase H-Cluster. J Am Chem Soc 2016; 138:1146-9. [PMID: 26764535 DOI: 10.1021/jacs.5b12512] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Three maturase enzymes-HydE, HydF, and HydG-synthesize and insert the organometallic component of the [FeFe]-hydrogenase active site (the H-cluster). HydG generates the first organometallic intermediates in this process, ultimately producing an [Fe(CO)2(CN)] complex. A limitation in understanding the mechanism by which this complex forms has been uncertainty regarding the precise metallocluster composition of HydG that comprises active enzyme. We herein show that the HydG auxiliary cluster must bind both l-cysteine and a dangler Fe in order to generate the [Fe(CO)2(CN)] product. These findings support a mechanistic framework in which a [(Cys)Fe(CO)2(CN)](-) species is a key intermediate in H-cluster maturation.
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Affiliation(s)
- Daniel L M Suess
- Department of Chemistry, University of California, Davis , Davis, California 95616, United States
| | - Cindy C Pham
- Department of Chemistry, University of California, Davis , Davis, California 95616, United States
| | | | | | - Stephen P Cramer
- Department of Chemistry, University of California, Davis , Davis, California 95616, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis , Davis, California 95616, United States
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Suess DLM, Kuchenreuther JM, De La Paz L, Swartz JR, Britt RD. Biosynthesis of the [FeFe] Hydrogenase H Cluster: A Central Role for the Radical SAM Enzyme HydG. Inorg Chem 2016; 55:478-87. [PMID: 26703931 PMCID: PMC4780679 DOI: 10.1021/acs.inorgchem.5b02274] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hydrogenase enzymes catalyze the rapid and reversible interconversion of H2 with protons and electrons. The active site of the [FeFe] hydrogenase is the H cluster, which consists of a [4Fe-4S]H subcluster linked to an organometallic [2Fe]H subcluster. Understanding the biosynthesis and catalytic mechanism of this structurally unusual active site will aid in the development of synthetic and biological hydrogenase catalysts for applications in solar fuel generation. The [2Fe]H subcluster is synthesized and inserted by three maturase enzymes-HydE, HydF, and HydG-in a complex process that involves inorganic, organometallic, and organic radical chemistry. HydG is a member of the radical S-adenosyl-l-methionine (SAM) family of enzymes and is thought to play a prominent role in [2Fe]H subcluster biosynthesis by converting inorganic Fe(2+), l-cysteine (Cys), and l-tyrosine (Tyr) into an organometallic [(Cys)Fe(CO)2(CN)](-) intermediate that is eventually incorporated into the [2Fe]H subcluster. In this Forum Article, the mechanism of [2Fe]H subcluster biosynthesis is discussed with a focus on how this key [(Cys)Fe(CO)2(CN)](-) species is formed. Particular attention is given to the initial metallocluster composition of HydG, the modes of substrate binding (Fe(2+), Cys, Tyr, and SAM), the mechanism of SAM-mediated Tyr cleavage to CO and CN(-), and the identification of the final organometallic products of the reaction.
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Affiliation(s)
- Daniel L. M. Suess
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Jon M. Kuchenreuther
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Liliana De La Paz
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - James R. Swartz
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - R. David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
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Ji X, Liu WQ, Yuan S, Yin Y, Ding W, Zhang Q. Mechanistic study of the radical SAM-dependent amine dehydrogenation reactions. Chem Commun (Camb) 2016; 52:10555-8. [DOI: 10.1039/c6cc05661j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Radical SAM-dependent amine dehydrogenation of tryptophan andl–tyrosine has resulted from the 5′-deoxyadenosyl radical-mediated hydrogen abstraction from the Cα of the substrates.
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Affiliation(s)
- Xinjian Ji
- Department of Chemistry
- Fudan University
- Shanghai
- China
| | - Wan-Qiu Liu
- Department of Chemistry
- Fudan University
- Shanghai
- China
- School of Life Sciences
| | - Shuguang Yuan
- Institute of Chemical Sciences and Engineering
- Ecole Polytechnique Fédérale de Lausanne (EPFL)
- Lausanne
- Switzerland
| | - Yue Yin
- Department of Chemistry
- Fudan University
- Shanghai
- China
| | - Wei Ding
- Department of Chemistry
- Fudan University
- Shanghai
- China
- School of Life Sciences
| | - Qi Zhang
- Department of Chemistry
- Fudan University
- Shanghai
- China
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CO and CN- syntheses by [FeFe]-hydrogenase maturase HydG are catalytically differentiated events. Proc Natl Acad Sci U S A 2015; 113:104-9. [PMID: 26699472 DOI: 10.1073/pnas.1515842113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The synthesis and assembly of the active site [FeFe] unit of [FeFe]-hydrogenases require at least three maturases. The radical S-adenosyl-l-methionine HydG, the best characterized of these proteins, is responsible for the synthesis of the hydrogenase CO and CN(-) ligands from tyrosine-derived dehydroglycine (DHG). We speculated that CN(-) and the CO precursor (-):CO2H may be generated through an elimination reaction. We tested this hypothesis with both wild type and HydG variants defective in second iron-sulfur cluster coordination by measuring the in vitro production of CO, CN(-), and (-):CO2H-derived formate. We indeed observed formate production under these conditions. We conclude that HydG is a multifunctional enzyme that produces DHG, CN(-), and CO at three well-differentiated catalytic sites. We also speculate that homocysteine, cysteine, or a related ligand could be involved in Fe(CO)x(CN)y transfer to the HydF carrier/scaffold.
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Abstract
Proton reduction and H2 oxidation are key elementary reactions for solar fuel production. Hydrogenases interconvert H+ and H2 with remarkable efficiency and have therefore received much attention in this context. For [FeFe]-hydrogenases, catalysis occurs at a unique cofactor called the H-cluster. In this article, we discuss ways in which EPR spectroscopy has elucidated aspects of the bioassembly of the H-cluster, with a focus on four case studies: EPR spectroscopic identification of a radical en route to the CO and CN- ligands of the H-cluster, tracing 57Fe from the maturase HydG into the H-cluster, characterization of the auxiliary Fe-S cluster in HydG, and isotopic labeling of the CN- ligands of HydA for electronic structure studies of its Hox state. Advances in cell-free maturation protocols have enabled several of these mechanistic studies, and understanding H-cluster maturation may in turn provide insights leading to improvements in hydrogenase production for biotechnological applications.
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Affiliation(s)
- Daniel L. M. Suess
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - R. David Britt
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
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Cysteine as a ligand platform in the biosynthesis of the FeFe hydrogenase H cluster. Proc Natl Acad Sci U S A 2015; 112:11455-60. [PMID: 26324916 DOI: 10.1073/pnas.1508440112] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Hydrogenases catalyze the redox interconversion of protons and H2, an important reaction for a number of metabolic processes and for solar fuel production. In FeFe hydrogenases, catalysis occurs at the H cluster, a metallocofactor comprising a [4Fe-4S]H subcluster coupled to a [2Fe]H subcluster bound by CO, CN(-), and azadithiolate ligands. The [2Fe]H subcluster is assembled by the maturases HydE, HydF, and HydG. HydG is a member of the radical S-adenosyl-L-methionine family of enzymes that transforms Fe and L-tyrosine into an [Fe(CO)2(CN)] synthon that is incorporated into the H cluster. Although it is thought that the site of synthon formation in HydG is the "dangler" Fe of a [5Fe] cluster, many mechanistic aspects of this chemistry remain unresolved including the full ligand set of the synthon, how the dangler Fe initially binds to HydG, and how the synthon is released at the end of the reaction. To address these questions, we herein show that L-cysteine (Cys) binds the auxiliary [4Fe-4S] cluster of HydG and further chelates the dangler Fe. We also demonstrate that a [4Fe-4S]aux[CN] species is generated during HydG catalysis, a process that entails the loss of Cys and the [Fe(CO)2(CN)] fragment; on this basis, we suggest that Cys likely completes the coordination sphere of the synthon. Thus, through spectroscopic analysis of HydG before and after the synthon is formed, we conclude that Cys serves as the ligand platform on which the synthon is built and plays a role in both Fe(2+) binding and synthon release.
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