1
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Wilson DWN, Thompson BC, Collauto A, Hooper RX, Knapp CE, Roessler MM, Musgrave RA. Mixed Valence {Ni 2+Ni 1+} Clusters as Models of Acetyl Coenzyme A Synthase Intermediates. J Am Chem Soc 2024; 146:21034-21043. [PMID: 39023163 PMCID: PMC11295191 DOI: 10.1021/jacs.4c06241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 07/20/2024]
Abstract
Acetyl coenzyme A synthase (ACS) catalyzes the formation and deconstruction of the key biological metabolite, acetyl coenzyme A (acetyl-CoA). The active site of ACS features a {NiNi} cluster bridged to a [Fe4S4]n+ cubane known as the A-cluster. The mechanism by which the A-cluster functions is debated, with few model complexes able to replicate the oxidation states, coordination features, or reactivity proposed in the catalytic cycle. In this work, we isolate the first bimetallic models of two hypothesized intermediates on the paramagnetic pathway of the ACS function. The heteroligated {Ni2+Ni1+} cluster, [K(12-crown-4)2][1], effectively replicates the coordination number and oxidation state of the proposed "Ared" state of the A-cluster. Addition of carbon monoxide to [1]- allows for isolation of a dinuclear {Ni2+Ni1+(CO)} complex, [K(12-crown-2)n][2] (n = 1-2), which bears similarity to the "ANiFeC" enzyme intermediate. Structural and electronic properties of each cluster are elucidated by X-ray diffraction, nuclear magnetic resonance, cyclic voltammetry, and UV/vis and electron paramagnetic resonance spectroscopies, which are supplemented by density functional theory (DFT) calculations. Calculations indicate that the pseudo-T-shaped geometry of the three-coordinate nickel in [1]- is more stable than the Y-conformation by 22 kcal mol-1, and that binding of CO to Ni1+ is barrierless and exergonic by 6 kcal mol-1. UV/vis absorption spectroscopy on [2]- in conjunction with time-dependent DFT calculations indicates that the square-planar nickel site is involved in electron transfer to the CO π*-orbital. Further, we demonstrate that [2]- promotes thioester synthesis in a reaction analogous to the production of acetyl coenzyme A by ACS.
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Affiliation(s)
- Daniel W. N. Wilson
- Department
of Chemistry, King’s College London, 7 Trinity Street, London SE1 1DB, U.K.
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Benedict C. Thompson
- Department
of Chemistry, King’s College London, 7 Trinity Street, London SE1 1DB, U.K.
| | - Alberto Collauto
- Department
of Chemistry and Centre for Pulse EPR Spectroscopy, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
| | - Reagan X. Hooper
- Stanford
PULSE Institute, SLAC National Accelerator
Laboratory, Menlo Park, California 94025, United States
| | - Caroline E. Knapp
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Maxie M. Roessler
- Department
of Chemistry and Centre for Pulse EPR Spectroscopy, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
| | - Rebecca A. Musgrave
- Department
of Chemistry, King’s College London, 7 Trinity Street, London SE1 1DB, U.K.
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2
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Zhai Y, Tong S, Chen L, Zhang Y, Amin FR, Khalid H, Liu F, Duan Y, Chen W, Chen G, Li D. The enhancement of energy supply in syngas-fermenting microorganisms. ENVIRONMENTAL RESEARCH 2024; 252:118813. [PMID: 38574985 DOI: 10.1016/j.envres.2024.118813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
After the second industrial revolution, social productivity developed rapidly, and the use of fossil fuels such as coal, oil, and natural gas increased greatly in industrial production. The burning of these fossil fuels releases large amounts of greenhouse gases such as CO2, which has caused greenhouse effects and global warming. This has endangered the planet's ecological balance and brought many species, including animals and plants, to the brink of extinction. Thus, it is crucial to address this problem urgently. One potential solution is the use of syngas fermentation with microbial cell factories. This process can produce chemicals beneficial to humans, such as ethanol as a fuel while consuming large quantities of harmful gases, CO and CO2. However, syngas-fermenting microorganisms often face a metabolic energy deficit, resulting in slow cell growth, metabolic disorders, and low product yields. This problem limits the large-scale industrial application of engineered microorganisms. Therefore, it is imperative to address the energy barriers of these microorganisms. This paper provides an overview of the current research progress in addressing energy barriers in bacteria, including the efficient capture of external energy and the regulation of internal energy metabolic flow. Capturing external energy involves summarizing studies on overexpressing natural photosystems and constructing semiartificial photosynthesis systems using photocatalysts. The regulation of internal energy metabolic flows involves two parts: regulating enzymes and metabolic pathways. Finally, the article discusses current challenges and future perspectives, with a focus on achieving both sustainability and profitability in an economical and energy-efficient manner. These advancements can provide a necessary force for the large-scale industrial application of syngas fermentation microbial cell factories.
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Affiliation(s)
- Yida Zhai
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China; School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Sheng Tong
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Limei Chen
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Yuan Zhang
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Farrukh Raza Amin
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Habiba Khalid
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Fuguo Liu
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China; School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Yu Duan
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China; School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Wuxi Chen
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Guofu Chen
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China.
| | - Demao Li
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China.
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3
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Taut J, Chambron J, Kersting B. Fifty Years of Inorganic Biomimetic Chemistry: From the Complexation of Single Metal Cations to Polynuclear Metal Complexes by Multidentate Thiolate Ligands. Eur J Inorg Chem 2023. [DOI: 10.1002/ejic.202200739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- Josef Taut
- Institut für Anorganische Chemie Universität Leipzig Johannisallee 29 04103 Leipzig Germany
- Institut de Chimie de Strasbourg UMR 7177 CNRS-Université de Strasbourg 1, rue Blaise Pascal 67008 Strasbourg France
| | - Jean‐Claude Chambron
- Institut de Chimie de Strasbourg UMR 7177 CNRS-Université de Strasbourg 1, rue Blaise Pascal 67008 Strasbourg France
| | - Berthold Kersting
- Institut für Anorganische Chemie Universität Leipzig Johannisallee 29 04103 Leipzig Germany
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4
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Zhao T, Ji M, Wang P, Li S, Pu X, Yang M. Polymorphism in acetyl-CoA synthase mimic complex [NiN2S2-(W(CO)5)2]. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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5
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Nickel(II)‐Mediated Reversible Thiolate/Disulfide Conversion as a Mimic for a Key Step of the Catalytic Cycle of Methyl‐Coenzyme M Reductase. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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6
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Bhandari A, Mishra S, Maji RC, Kumar A, Olmstead MM, Patra AK. Nickel(II)‐Mediated Reversible Thiolate/Disulfide Conversion as a Mimic for a Key Step of the Catalytic Cycle of Methyl‐Coenzyme M Reductase. Angew Chem Int Ed Engl 2020; 59:9177-9185. [DOI: 10.1002/anie.202001363] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Indexed: 01/22/2023]
Affiliation(s)
- Anirban Bhandari
- Department of Chemistry National Institute of Technology Durgapur Mahatma Gandhi Avenue Durgapur 713 209 (WB) India
| | - Saikat Mishra
- Department of Chemistry National Institute of Technology Durgapur Mahatma Gandhi Avenue Durgapur 713 209 (WB) India
| | - Ram Chandra Maji
- Department of Chemistry National Institute of Technology Durgapur Mahatma Gandhi Avenue Durgapur 713 209 (WB) India
| | - Akhilesh Kumar
- Department of Chemistry Indian Institute of Technology Kanpur Kanpur 208016 India
| | | | - Apurba K. Patra
- Department of Chemistry National Institute of Technology Durgapur Mahatma Gandhi Avenue Durgapur 713 209 (WB) India
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Alfano M, Cavazza C. Structure, function, and biosynthesis of nickel-dependent enzymes. Protein Sci 2020; 29:1071-1089. [PMID: 32022353 DOI: 10.1002/pro.3836] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 01/23/2020] [Accepted: 01/23/2020] [Indexed: 12/17/2022]
Abstract
Nickel enzymes, present in archaea, bacteria, plants, and primitive eukaryotes are divided into redox and nonredox enzymes and play key functions in diverse metabolic processes, such as energy metabolism and virulence. They catalyze various reactions by using active sites of diverse complexities, such as mononuclear nickel in Ni-superoxide dismutase, glyoxylase I and acireductone dioxygenase, dinuclear nickel in urease, heteronuclear metalloclusters in [NiFe]-carbon monoxide dehydrogenase, acetyl-CoA decarbonylase/synthase and [NiFe]-hydrogenase, and even more complex cofactors in methyl-CoM reductase and lactate racemase. The presence of metalloenzymes in a cell necessitates a tight regulation of metal homeostasis, in order to maintain the appropriate intracellular concentration of nickel while avoiding its toxicity. As well, the biosynthesis and insertion of nickel active sites often require specific and elaborated maturation pathways, allowing the correct metal to be delivered and incorporated into the target enzyme. In this review, the phylogenetic distribution of nickel enzymes will be briefly described. Their tridimensional structures as well as the complexity of their active sites will be discussed. In view of the latest findings on these enzymes, a special focus will be put on the biosynthesis of their active sites and nickel activation of apo-enzymes.
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Affiliation(s)
- Marila Alfano
- University of Grenoble Alpes, CEA, CNRS, IRIG, CBM, Grenoble, France
| | - Christine Cavazza
- University of Grenoble Alpes, CEA, CNRS, IRIG, CBM, Grenoble, France
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8
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Alfano M, Veronesi G, Musiani F, Zambelli B, Signor L, Proux O, Rovezzi M, Ciurli S, Cavazza C. A Solvent‐Exposed Cysteine Forms a Peculiar Ni
II
‐Binding Site in the Metallochaperone CooT from
Rhodospirillum rubrum. Chemistry 2019; 25:15351-15360. [DOI: 10.1002/chem.201903492] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Marila Alfano
- IRIG, CBMUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
| | - Giulia Veronesi
- IRIG, CBMUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
| | - Francesco Musiani
- Laboratory of Bioinorganic ChemistryDepartment of Pharmacy and BiotechnologyUniversity of Bologna Via Giuseppe Fanin 40 40127 Bologna Italy
| | - Barbara Zambelli
- Laboratory of Bioinorganic ChemistryDepartment of Pharmacy and BiotechnologyUniversity of Bologna Via Giuseppe Fanin 40 40127 Bologna Italy
| | - Luca Signor
- IRIG, IBSUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
| | - Olivier Proux
- OSUG, FAMEUniversity of Grenoble Alpes, CNRS, IRDIrstea, Météo France 38000 Grenoble France
| | - Mauro Rovezzi
- OSUG, FAMEUniversity of Grenoble Alpes, CNRS, IRDIrstea, Météo France 38000 Grenoble France
| | - Stefano Ciurli
- Laboratory of Bioinorganic ChemistryDepartment of Pharmacy and BiotechnologyUniversity of Bologna Via Giuseppe Fanin 40 40127 Bologna Italy
| | - Christine Cavazza
- IRIG, CBMUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
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9
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Bhandari A, Chandra Maji R, Mishra S, Kumar A, Barman SK, Das PP, Ghiassi KB, Olmstead MM, Patra AK. Model Complexes for the Nip Site of Acetyl Coenzyme A Synthase/Carbon Monoxide (CO) Dehydrogenase: Structure, Electrochemistry, and CO Reactivity. Inorg Chem 2018; 57:13713-13727. [DOI: 10.1021/acs.inorgchem.8b02276] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anirban Bhandari
- Department of Chemistry, National Institute of Technology Durgapur, Mahatma Gandhi Avenue, Durgapur 713209, India
| | - Ram Chandra Maji
- Department of Chemistry, National Institute of Technology Durgapur, Mahatma Gandhi Avenue, Durgapur 713209, India
| | - Saikat Mishra
- Department of Chemistry, National Institute of Technology Durgapur, Mahatma Gandhi Avenue, Durgapur 713209, India
| | - Akhilesh Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Suman Kumar Barman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Partha Pratim Das
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Kamran B. Ghiassi
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Marilyn M. Olmstead
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Apurba K. Patra
- Department of Chemistry, National Institute of Technology Durgapur, Mahatma Gandhi Avenue, Durgapur 713209, India
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10
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Denny JA, Darensbourg MY. Metallodithiolates as ligands in coordination, bioinorganic, and organometallic chemistry. Chem Rev 2015; 115:5248-73. [PMID: 25948147 DOI: 10.1021/cr500659u] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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11
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Pinder TA, Montalvo SK, Lunsford AM, Hsieh CH, Reibenspies JH, Darensbourg MY. Versatile N2S2nickel-dithiolates as mono- and bridging bidentate, S-donor ligands to gold(i). Dalton Trans 2014; 43:138-44. [DOI: 10.1039/c3dt52295d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Hosler ER, Herbst RW, Maroney MJ, Chohan BS. Exhaustive oxidation of a nickel dithiolate complex: some mechanistic insights en route to sulfate formation. Dalton Trans 2012; 41:804-16. [DOI: 10.1039/c1dt11032b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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13
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Ponikiewski Ł, Pladzyk A, Wojnowski W, Becker B. Nickel(II) tri-tert-butoxysilanethiolates with N-heterocyclic bases as additional ligands: Synthesis, molecular structure and spectral studies. Polyhedron 2011. [DOI: 10.1016/j.poly.2011.06.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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14
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Mathrubootham V, Thomas J, Staples R, McCraken J, Shearer J, Hegg EL. Bisamidate and mixed amine/amidate NiN2S2 complexes as models for nickel-containing acetyl coenzyme A synthase and superoxide dismutase: an experimental and computational study. Inorg Chem 2010; 49:5393-406. [PMID: 20507077 PMCID: PMC2898278 DOI: 10.1021/ic9023053] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The distal nickel site of acetyl-CoA synthase (Ni(d)-ACS) and reduced nickel superoxide dismutase (Ni-SOD) display similar square-planar Ni(II)N(2)S(2) coordination environments. One difference between these two sites, however, is that the nickel ion in Ni-SOD contains a mixed amine/amidate coordination motif while the Ni(d) site in Ni-ACS contains a bisamidate coordination motif. To provide insight into the consequences of the different coordination environments on the properties of the Ni ions, we systematically examined two square-planar Ni(II)N(2)S(2) complexes, one with bisthiolate-bisamidate ligation (Et(4)N)(2)(Ni(L1)).2H(2)O (2) [H(4)L1 = N-(2-mercaptoacetyl)-N'-(2-mercaptoethyl)glycinamide] and another with bisthiolate-amine/amidate ligation K(Ni(HL2)) (3) [H(4)L2 = N-(2''-mercaptoethyl)-2-((2'-mercaptoethyl)amino)acetamide]. Although these two complexes differ only by a single amine versus amidate ligand, their chemical properties are quite different. The stronger in-plane ligand field in the bisamidate complex (Ni(II)(L1))(2-) (2) results in an increase in the energies of the d --> d transitions and a considerably more negative oxidation potential. Furthermore, while the bisamidate complex (Ni(II)(L1))(2-) (2) readily forms a trinuclear species (Et(4)N)(2)({Ni(L1)}(2)Ni).H(2)O (1) and reacts rapidly with O(2), presumably via sulfoxidation, the mixed amine/amidate complex (Ni(II)(HL2))(-) (3) remains monomeric and is stable for days in air. Interestingly, the Ni(III) species of the bisamidate complex formed by chemical oxidation with I(2) can be detected by electron paramagnetic resonance (EPR) spectroscopy while the mixed amine/amidate complex immediately decomposes upon oxidation. To explain these experimentally observed properties, we performed S K-edge X-ray absorption spectroscopy and low-temperature (77 K) electronic absorption measurements as well as both hybrid density functional theory (hybrid-DFT) and spectroscopy oriented configuration interaction (SORCI) calculations. These studies demonstrate that the highest occupied molecular orbital (HOMO) of the bisamidate complex (Ni(II)(L1))(2-) (2) has more Ni character and is significantly destabilized relative to the mixed amine/amidate complex (Ni(II)(HL2))(-) (3) by approximately 6.2 kcal mol(-1). The consequence of this destabilization is manifested in the nucleophilic activation of the doubly filled HOMO, which makes (Ni(II)(L1))(2-) (2) significantly more reactive toward electrophiles such as O(2).
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Affiliation(s)
| | - Jason Thomas
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - Richard Staples
- Department of Chemistry, Michigan State University, East Lansing, MI 48824
| | - John McCraken
- Department of Chemistry, Michigan State University, East Lansing, MI 48824
| | - Jason Shearer
- Department of Chemistry, University of Nevada, Reno, NV 89557
| | - Eric L. Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824
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15
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McGuinness ET. Some Molecular Moments of the Hadean and Archaean Aeons: A Retrospective Overview from the Interfacing Years of the Second to Third Millennia. Chem Rev 2010; 110:5191-215. [DOI: 10.1021/cr050061l] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Eugene T. McGuinness
- Department of Chemistry & Biochemistry, Seton Hall University, South Orange, New Jersey 07079-2690
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16
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Green KN, Brothers SM, Lee B, Darensbourg MY, Rockcliffe DA. Chemical issues addressing the construction of the distal Ni[cysteine-glycine-cysteine]2- site of acetyl CoA synthase: why not copper? Inorg Chem 2009; 48:2780-92. [PMID: 19253985 DOI: 10.1021/ic801628r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The discovery of the metallopeptide Ni(Cysteine-Glycine-Cysteine)(2-), Ni(CGC)(2-), in the A-cluster active site of Acetyl CoA Synthase has prompted the synthesis of many small molecule models which employ M(N(2)S(2)) complexes as metalloligands. In vitro studies have shown that nickel incorporates into the N(2)S(2) binding pocket even when copper is in the enzyme growth medium, while copper is preferentially taken up in the proximal site, displacing the catalytically active nickel. (Darnault, C.; Volbeda, A.; Kim, E.J.; Legrand, P.; Vernede, X.; Lindahl, P.A.; Fontecilla-Camps, J.C. Nat. Struct. Biol. 2003, 10, 271-279.) The work herein has been designed to address the chemical viability of copper(II) within the tripeptide N(2)S(2) ligand set. To this end, a series of CuN(2)S(2)(2-) complexes, the resin-bound, O-Cu(CGC)(2-) (A) and free Cu(CGC)(2-) (B) complexes, as well as Cu(ema)(2-) (C) and Cu(emi)(2-) (D) dianions, have been characterized by UV-vis, electron paramagnetic resonance (EPR), and electrospray ionization mass spectrometry (ESI-MS) spectroscopies, cyclic voltammetry (CV), and, where appropriate, X-ray diffraction studies, and compared to the Ni(II) congeners. EPR spectroscopic results have indicated that, in frozen N,N-dimethylformamide (DMF) solution, the copper complexes are distorted square planar structures with nitrogen and sulfur donors. This is consistent with X-ray diffraction measurements which also show copper(II) in a distorted square planar environment that is bereft of CuN(2)S(2)(2-) intermolecular interactions. Density-functional theory (DFT) calculations resulted in optimized structures that are consistent with crystallographic data and indicated highest occupied molecular orbital (HOMO)-singly occupied molecular orbital (SOMO) gaps of 5.01 and 4.68 eV for C and D, respectively. Optimized structures of Ni(ema)(2-) and Ni(emi)(2-) share the same basic characteristics as the copper(II) congeners. Electrochemical characterization of C and D resulted in a reversible Cu(III/II) couple at -1.20 V and - 1.40 V, respectively. Reactivity studies with Rh(CO)(2)(+) show similar donor capabilities for complexes A-D. Analysis of A shows that transmetalation does not occur. From competitive metal uptake studies on immobilized tripeptide it is concluded that the N(2)S(2)(4-) ligating unit has a slight preference for Cu(2+) over Ni(2+) and that the biosynthetic pathway responsible for constructing the distal site of ACS must be selective for nickel insertion or copper exclusion, or both.
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Affiliation(s)
- Kayla N Green
- Department of Chemistry, Texas A&M University, College Station, Texas 77845, USA
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17
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Ariyananda PWG, Kieber-Emmons MT, Yap GPA, Riordan CG. Synthetic analogs for evaluating the influence of N-H...S hydrogen bonds on the formation of thioester in acetyl coenzyme A synthase. Dalton Trans 2009:4359-69. [PMID: 19662314 DOI: 10.1039/b901192g] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of square planar methylnickel(II) complexes, (dppe)Ni(Me)(SAr) (dppe = 1,2-bis(diphenylphosphino)ethane); 2. Ar = phenyl; 3. Ar = pentafluorophenyl; 4. Ar = o-pivaloylaminophenyl; 5. Ar = p-pivaloylaminophenyl; (depe)Ni(Me)(SAr), (depe = 1,2-bis(diethylphosphino)ethane); 7. Ar = phenyl; 8. Ar = pentafluorophenyl; 9. Ar = o-pivaloylaminophenyl; 10. Ar = p-pivaloylaminophenyl), were synthesized via the reaction of (dppe)NiMe(2) (1) and (depe)NiMe(2) (6) with either the corresponding thiol or disulfide. These complexes were characterized by various spectroscopic methods including (31)P NMR, (1)H NMR, (13)C NMR and infrared spectroscopies and in most cases by X-ray diffraction analyses. Solid state and solution measurements establish that 4 and 9 contain intramolecular N-H...S bonds. Carbonylation of the complexes 2-4, 7-10 leads to (dRpe)Ni(CO)(2) and MeC(O)SAr via the intermediacy of the acylnickel adducts, (dRpe)Ni(C(O)Me)(SAr), detected at low temperature by (31)P NMR spectroscopy. Consistent with experimental observations, density functional theory results reveal that the intramolecular hydrogen bond in 9 stabilizes the acylnickel adduct compared with its non-hydrogen-bonded adduct, 10. Oxidative addition of MeC(O)SC(6)F(5) to (dRpe)Ni(COD) followed by spontaneous decarbonylation proceeds in variable yields generating 3 and 8.
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Affiliation(s)
- Piyal W G Ariyananda
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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18
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Ito M, Kotera M, Song Y, Matsumoto T, Tatsumi K. Structural models for the active site of acetyl-CoA synthase: synthesis of dinuclear nickel complexes having thiolate, isocyanide, and thiourea on the Ni(p) site. Inorg Chem 2009; 48:1250-6. [PMID: 19128153 DOI: 10.1021/ic801967e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The trinuclear nickel complex [{Ni(dadt(Et))}(2)Ni](NiBr(4)) (dadt(Et) = N,N'-diethyl-3,7-diazanonane-1,9-dithiolate) (1a), prepared by the reaction of Ni(dadt(Et)) and Ni(EtOH)(4)Br(2), was found to serve as a useful synthetic precursor of various dinuclear nickel complexes modeling the active site of acetyl-CoA synthase (ACS). The reactions of 1a with 4 equiv of the potassium salts of arenethiolates in ethanol produced a series of dinuclear nickel thiolate complexes Ni(dadt(Et))Ni(SAr)(2) (Ar = Ph (2a), p-Tol (2b), 2,4,6-triisopropylphenyl (Tip) (2c)) in good yields. The analogous reactions of 1a with Ag(OTf) in the presence of (t)BuNC and (NMe(2))(2)CS (tmtu) generated the dicationic dinuclear nickel complexes [Ni(dadt(Et))Ni((t)BuNC)(2)](OTf)(2) (3) and [Ni(dadt(Et))Ni(tmtu)(2)](OTf)(2) (4), respectively. The molecular structures of 1a, 2a-c, 3, and 4 determined by X-ray analysis compare well with that of A-cluster in ACS.
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Affiliation(s)
- Mikinao Ito
- Research Center for Materials Science, and Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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Song Y, Ito M, Kotera M, Matsumoto T, Tatsumi K. Cationic and Anionic Dinuclear Nickel Complexes [Ni(N2S2)Ni(dtc)]n(n=−1, +1) Modeling the Active Site of Acetyl-CoA Synthase. CHEM LETT 2009. [DOI: 10.1246/cl.2009.184] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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A paramagnetic trigonal paddlewheel complex with iron-dithiolato ligand paddles: {[(C9H18N2S2)Fe(NO)]3Ag2}(BF4)2. J Mol Struct 2008. [DOI: 10.1016/j.molstruc.2008.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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21
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Dougherty WG, Rangan K, O'Hagan MJ, Yap GPA, Riordan CG. Binuclear complexes containing a methylnickel moiety: relevance to organonickel intermediates in acetyl coenzyme A synthase catalysis. J Am Chem Soc 2008; 130:13510-1. [PMID: 18800791 DOI: 10.1021/ja803795k] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of binuclear NiNi complexes supported by a single thiolate bridge and containing a methylnickel moiety have been prepared and fully characterized. The complexes represent structural analogues for the proposed organonickel intermediate in the acetyl coenzyme A synthase catalytic cycle. Variable temperature 31P NMR spectroscopy was used to examine dynamic behavior of the thiolate bridging interaction in two of the derivatives. Kinetic analyses, independent exchange and crossover experiments support an intermolecular exchange mechanism. Carbonylation results in thioester formation via a reductive elimination pathway.
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Affiliation(s)
- William G Dougherty
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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22
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Eckert NA, Dougherty WG, Yap GPA, Riordan CG. Methyl transfer from methylcobaloxime to (triphos)Ni(PPh(3)): relevance to the mechanism of acetyl coenzyme A synthase. J Am Chem Soc 2007; 129:9286-7. [PMID: 17622143 DOI: 10.1021/ja072063o] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nathan A Eckert
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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Sharma SK, Upreti S, Gupta R. Effect of Ligand Architecture on the Structure and Properties of Square-Planar Nickel(II) Complexes of Amide-Based Macrocycles. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200700122] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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24
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Redin K, Wilson AD, Newell R, DuBois MR, DuBois DL. Studies of Structural Effects on the Half-Wave Potentials of Mononuclear and Dinuclear Nickel(II) Diphosphine/Dithiolate Complexes. Inorg Chem 2007; 46:1268-76. [PMID: 17249658 DOI: 10.1021/ic061740x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two series of mononuclear Ni(II) complexes of the formula (PNP)Ni(dithiolate) where PNP = R2PCH2N(CH3)CH2PR2, R = Et and Ph, have been synthesized containing dithiolate ligands that vary from five- to seven-membered chelate rings. Two series of dinuclear Ni(II) complexes of the formula {[(diphosphine)Ni]2(dithiolate)}(X)2 (X = BF4 or PF6) have been synthesized in which the chelate ring size of the dithiolate and diphosphine ligands have been systematically varied. The structures of the alkylated mononuclear complex, [(PNPEt)Ni(SC2H4SMe)]OTf, and the dinuclear complex, [(dppeNi)2(SC3H6S)](BF4)2, have been determined by X-ray diffraction studies. The complexes have been studied by cyclic voltammetry to determine how the half-wave potentials of the Ni(II/I) couples vary with chelate ring size of the ligands. For the mononuclear complexes, this potential becomes more positive as the natural bite angle of the dithiolate ligand increases. However, the potentials of the Ni(II/I) couples of the dinuclear complexes do not show a dependence on the chelate ring size of the ligands. Other aspects of the reduction chemistry of these complexes have been explored.
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Affiliation(s)
- Kendra Redin
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
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Jeffery SP, Singleton ML, Reibenspies JH, Darensbourg MY. Control of S-Based Aggregation: Designed Synthesis of NiM2 and Ni2M Trinuclear Complexes. Inorg Chem 2006; 46:179-85. [PMID: 17198426 DOI: 10.1021/ic061475f] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modification of the nickel dithiolate metalloligand, Ni(bme-daco) [where bme-daco = bis(mercaptoethyl)diazacyclooctane] or Ni-1, by oxygenation of one thiolate into a sulfinate, Ni(mese-daco) [where mese-daco = (mercaptoethyl)(sulfinatoethyl)diazacyclooctane] or Ni-2, restricts the ligating ability to monodentate and is expected to reduce the donor ability of the remaining thiolate S. Nevertheless, the Ni-2 complex forms a stable thiolate S-bound adduct of W0(CO)5, (Ni-2)W(CO)5, a complex whose upsilon(CO) IR spectrum reports insignificant differences in the donor abilities of Ni-1 and Ni-2 in (eta1-NiN2S2)W(CO)5 complexes. In the presence of the strong sulfophile CuI, a CuNi2 trimetallic, (Ni-2)2CuBr, was isolated. Another trimetallic, (mu-eta2-Ni-1)[W(CO)5]2, demonstrated the Ni(bme-daco), Ni-1, unit to bridge low-valent metals in a transoid configuration, yielding W-W distances of over 5 A.
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Affiliation(s)
- Stephen P Jeffery
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA
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Verhagen JAW, Tock C, Lutz M, Spek AL, Bouwman E. Nickel Thiolate Complexes as Ligands for Copper and Zinc: Novel Additions to a Library of Binding Modes. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600645] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Krishnamurthy D, Sarjeant AN, Goldberg DP, Caneschi A, Totti F, Zakharov LN, Rheingold AL. Mononuclear, Dinuclear, and Pentanuclear [{N,S(thiolate)}Iron(II)] Complexes: Nuclearity Control, Incorporation of Hydroxide Bridging Ligands, and Magnetic Behavior. Chemistry 2005; 11:7328-41. [PMID: 16144021 DOI: 10.1002/chem.200500156] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The mixed N3S(thiolate) ligand 1-[bis[2-(pyridin-2-yl)ethyl]amino]-2-methylpropane-2-thiol (Py2SH) was used in the synthesis of four iron(II) complexes: [(Py2S)FeCl] (1), [(Py2S)FeBr] (2), [(Py2S)4Fe5II(mu-OH)2](BF4)4 (3), and [(Py2S)2Fe2II(mu-OH)]BF4 (4). The X-ray structures of 1 and 2 revealed monomeric iron(II)-alkylthiolate complexes with distorted trigonal-bipyramidal geometries. The paramagnetic 1H NMR spectra of 1 and 2 display resonances from delta = -25 ppm to +100 ppm, consistent with a high-spin iron(II) ion (S = 2). Spectral assignments were made on the basis of chemical shift information and T1 measurements and show the monomeric structures are intact in solution. To provide entry into hydroxide-containing complexes, a novel synthetic method was developed involving strict aprotic conditions and limiting amounts of H2O. Reaction of Py2SH with NaH and Fe(BF4)2.6 H2O under aprotic conditions led to the isolation of the pentanuclear, mu-OH complex 3, which has a novel dimer-of-dimers type structure connected by a central iron atom. Conductivity data on 3 show this structure is retained in CH2Cl2. Rational modification of the ligand-to-metal ratio allows control over the nuclearity of the product, yielding the dinuclear complex 4. The X-ray structure of 4 reveals an unprecedented face-sharing, biooctahedral complex with an [S2O] bridging arrangement. The magnetic properties of 3 and 4 in the range 1.9-300 K were successfully modeled. Dinuclear 4 is antiferromagnetically coupled [J = -18.8(2) cm(-1)]. Pentanuclear 3 exhibits ferrimagnetic behavior, with a high-spin ground state of S(T) = 6, and was best modeled with three different exchange parameters [J = -15.3(2), J' = -24.7(3), and J'' = -5.36(7) cm(-1)]. DFT calculations provided good support for the interpretation of the magnetic properties.
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Affiliation(s)
- Divya Krishnamurthy
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
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Harrop TC, Mascharak PK. Structural and spectroscopic models of the A-cluster of acetyl coenzyme a synthase/carbon monoxide dehydrogenase: Nature's Monsanto acetic acid catalyst. Coord Chem Rev 2005. [DOI: 10.1016/j.ccr.2005.04.019] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Riordan CG. Synthetic chemistry and chemical precedents for understanding the structure and function of acetyl coenzyme A synthase. J Biol Inorg Chem 2004; 9:542-9. [PMID: 15221481 DOI: 10.1007/s00775-004-0567-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Accepted: 05/21/2004] [Indexed: 10/26/2022]
Abstract
Acetyl coenzyme A synthase (ACS), found in acetogenic and methanogenic organisms, is responsible for the synthesis and breakdown of acetate. The mechanism by which methylcob(III)alamin, CO and coenzyme A are assembled/disassembled at the active-site A-cluster involves a number of biologically unprecedented intermediates. In the past two years, two protein crystal structures have significantly enhanced the understanding of the structure of the active-site A-cluster, responsible for catalysis. The structure reports spawned a number of important questions regarding the metal ion constitution of the active enzyme, the structure(s) of the spectroscopically identified states and the details of the catalytic mechanism. This Commentary addresses these issues in the framework of existing synthetic and chemical precedent studies aimed at developing rational structure-function correlations and presents structural and reactivity targets for future studies.
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Affiliation(s)
- Charles G Riordan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
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Wang Q, Blake AJ, Davies ES, McInnes EJL, Wilson C, Schröder M. Structure and electronic properties of an asymmetric thiolate-bridged binuclear complex: a model for the active site of acetyl CoA synthase. Chem Commun (Camb) 2004:3012-3. [PMID: 14703833 DOI: 10.1039/b310183e] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The asymmetric binuclear complex [(dppe)Ni(mu-'S, S')Ni(L)](PF6)2 [L = (N, N'-diethyl-3,7-diazanonane-1,9-dithiolato)2-] shows a reversible one-electron reduction to afford a mixed-valent Ni(II) x Ni(I) species; the reduced complex has been characterised by EPR spectroscopy and mimics the redox active Nip site in the active A-cluster of acetyl coenzyme A synthase.
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Affiliation(s)
- Qiang Wang
- School of Chemistry, The University of Nottingham, Nottingham, UK NG7 2RD
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Hatlevik Ø, Blanksma MC, Mathrubootham V, Arif AM, Hegg EL. Modeling carbon monoxide dehydrogenase/acetyl-CoA synthase (CODH/ACS): a trinuclear nickel complex employing deprotonated amides and bridging thiolates. J Biol Inorg Chem 2004; 9:238-46. [PMID: 14735332 DOI: 10.1007/s00775-003-0518-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Accepted: 12/12/2003] [Indexed: 10/26/2022]
Abstract
Carbon monoxide dehydrogenase/acetyl-CoA synthase (CODH/ACS) utilizes a unique Ni-M bimetallic site in the biosynthesis of acetyl-CoA, where a square-planar Ni ion is coordinated to two thiolates and two deprotonated amides in a Cys-Gly-Cys motif. The identity of M is currently a matter of debate, although both Cu and Ni have been proposed. In an effort to model ACS's unusual active site and to provide insight into the mechanism of acetyl-CoA formation and the role of each of the metals ions, we have prepared and structurally characterized a number of Ni(II)-peptide mimic complexes. The mononuclear complexes Ni(II) N, N'-bis(2-mercaptoethyl)oxamide (1), Ni(II) N, N'-ethylenebis(2-mercaptoacetamide) (2), and Ni(II) N, N'-ethylenebis(2-mercaptopropionamide) (3) model the Ni(Cys-Gly-Cys) site and can be used as synthons for additional multinuclear complexes. Reaction of 2 with MeI resulted in the alkylation of the sulfur atoms and the formation of Ni(II) N, N'-ethylenebis(2-methylmercaptoacetamide) (4), demonstrating the nucleophilicity of the terminal alkyl thiolates. Addition of Ni(OAc)(2).4H(2)O to3 resulted in the formation of a trinuclear species (5), while 2 crystallizes as an unusual paddlewheel complex (6) in the presence of nickel acetate. The difference in reactivity between the similar complexes 2 and 3 highlights the importance of ligand design when synthesizing models of ACS. Significantly,5 maintains the key features observed in the active site of ACS, namely a square-planar Ni coordinated to two deprotonated amides and two thiolates, where the thiolates bridge to a second metal, suggesting that 5 is a reasonable structural model for this unique enzyme.
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Affiliation(s)
- Øyvind Hatlevik
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112-0850, USA
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Svetlitchnyi V, Dobbek H, Meyer-Klaucke W, Meins T, Thiele B, Römer P, Huber R, Meyer O. A functional Ni-Ni-[4Fe-4S] cluster in the monomeric acetyl-CoA synthase from Carboxydothermus hydrogenoformans. Proc Natl Acad Sci U S A 2004; 101:446-51. [PMID: 14699043 PMCID: PMC327167 DOI: 10.1073/pnas.0304262101] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2003] [Indexed: 11/18/2022] Open
Abstract
In anaerobic microorganisms employing the acetyl-CoA pathway, acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH) form a complex (ACS/CODH) that catalyzes the synthesis of acetyl-CoA from CO, a methyl group, and CoA. Previously, a [4Fe-4S] cubane bridged to a copper-nickel binuclear site (active site cluster A of the ACS component) was identified in the ACS(Mt)/CODH(Mt) from Moorella thermoacetica whereas another study revealed a nickel-nickel site in the open form of ACS(Mt), and a zink-nickel site in the closed form. The ACS(Ch) of the hydrogenogenic bacterium Carboxydothermus hydrogenoformans was found to exist as an 82.2-kDa monomer as well as in a 1:1 molar complex with the 73.3-kDa CODHIII(Ch). Homogeneous ACS(Ch) and ACS(Ch)/CODHIII(Ch) catalyzed the exchange between [1-(14)C]acetyl-CoA and (12)CO with specific activities of 2.4 or 5.9 micromol of CO per min per mg, respectively, at 70 degrees C and pH 6.0. They also catalyzed the synthesis of acetyl-CoA from CO, methylcobalamin, corrinoid iron-sulfur protein, and CoA with specific activities of 0.14 or 0.91 micromol of acetyl-CoA formed per min per mg, respectively, at 70 degrees C and pH 7.3. The functional cluster A of ACS(Ch) contains a Ni-Ni-[4Fe-4S] site, in which the positions proximal and distal to the cubane are occupied by Ni ions. This result is apparent from a positive correlation of the Ni contents and negative correlations of the Cu or Zn contents with the acetyl-CoA/CO exchange activities of different preparations of monomeric ACS(Ch), a 2.2-A crystal structure of the dithionite-reduced monomer in an open conformation, and x-ray absorption spectroscopy.
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Affiliation(s)
- Vitali Svetlitchnyi
- Lehrstuhl für Mikrobiologie, Universität Bayreuth, D-95440 Bayreuth, Germany.
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Golden M, Jeffery S, Miller M, Reibenspies J, Darensbourg M. The Construction of (N2S2)Ni−Pd Clusters: A Slant-Chair, a Basket and a C4-Paddlewheel Structure. Eur J Inorg Chem 2004. [DOI: 10.1002/ejic.200300675] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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