1
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Selvan D, Chakraborty S. A De Novo Designed Trimeric Metalloprotein as a Ni p Model of the Acetyl-CoA Synthase. Int J Mol Sci 2023; 24:10317. [PMID: 37373464 DOI: 10.3390/ijms241210317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/30/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
We present a Nip site model of acetyl coenzyme-A synthase (ACS) within a de novo-designed trimer peptide that self-assembles to produce a homoleptic Ni(Cys)3 binding motif. Spectroscopic and kinetic studies of ligand binding demonstrate that Ni binding stabilizes the peptide assembly and produces a terminal NiI-CO complex. When the CO-bound state is reacted with a methyl donor, a new species is quickly produced with new spectral features. While the metal-bound CO is albeit unactivated, the presence of the methyl donor produces an activated metal-CO complex. Selective outer sphere steric modifications demonstrate that the physical properties of the ligand-bound states are altered differently depending on the location of the steric modification above or below the Ni site.
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Affiliation(s)
- Dhanashree Selvan
- Department of Chemistry and Biochemistry, University of Mississippi, Coulter Hall, Oxford, MS 38677, USA
| | - Saumen Chakraborty
- Department of Chemistry and Biochemistry, University of Mississippi, Coulter Hall, Oxford, MS 38677, USA
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2
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Domergue J, Guinard P, Douillard M, Pécaut J, Hostachy S, Proux O, Lebrun C, Le Goff A, Maldivi P, Duboc C, Delangle P. A Series of Ni Complexes Based on a Versatile ATCUN-Like Tripeptide Scaffold to Decipher Key Parameters for Superoxide Dismutase Activity. Inorg Chem 2023. [PMID: 37247425 DOI: 10.1021/acs.inorgchem.3c00766] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The cellular level of reactive oxygen species (ROS) has to be controlled to avoid some pathologies, especially those linked to oxidative stress. One strategy for designing antioxidants consists of modeling natural enzymes involved in ROS degradation. Among them, nickel superoxide dismutase (NiSOD) catalyzes the dismutation of the superoxide radical anion, O2•-, into O2 and H2O2. We report here Ni complexes with tripeptides derived from the amino-terminal CuII- and NiII-binding (ATCUN) motif that mimics some structural features found in the active site of the NiSOD. A series of six mononuclear NiII complexes were investigated in water at physiological pH with different first coordination spheres, from compounds with a N3S to N2S2 set, and also complexes that are in equilibrium between the N-coordination (N3S) and S-coordination (N2S2). They were fully characterized by a combination of spectroscopic techniques, including 1H NMR, UV-vis, circular dichroism, and X-ray absorption spectroscopy, together with theoretical calculations and their redox properties studied by cyclic voltammetry. They all display SOD-like activity, with a kcat ranging between 0.5 and 2.0 × 106 M-1 s-1. The complexes in which the two coordination modes are in equilibrium are the most efficient, suggesting a beneficial effect of a nearby proton relay.
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Affiliation(s)
- Jérémy Domergue
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
| | - Pawel Guinard
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
| | - Magali Douillard
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
| | - Jacques Pécaut
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
| | - Sarah Hostachy
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
| | - Olivier Proux
- CNRS, OSUG, Université Grenoble Alpes, 38000 Grenoble, France
| | - Colette Lebrun
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
| | - Alan Le Goff
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France
| | - Pascale Maldivi
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
| | - Carole Duboc
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France
| | - Pascale Delangle
- IRIG, SyMMES, Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, 38000 Grenoble, France
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3
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Zhao J, Shi Q, Song D, Li B, Ren H, Zhang D, Sun X, Li J, Wang N. Effect of the NiN2S2 Metallothiolate Ligands on the Preparation, Structure, and Property of Dinickel Complexes Related to [NiFe]-Hydrogenases Active Site. Catal Letters 2022. [DOI: 10.1007/s10562-021-03627-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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4
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Sun P, Yang D, Li Y, Wang B, Qu J. A bioinspired thiolate-bridged dinickel complex with a pendant amine: synthesis, structure and electrocatalytic properties. Dalton Trans 2020; 49:2151-2158. [PMID: 31994565 DOI: 10.1039/c9dt04493k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
By employing X(CH2CH2S-)2 (X = S, tpdt; X = O, opdt; X = NPh, npdt) as bridging ligands, four thiolate-bridged dinickel complexes supported by phosphine ligands, [(dppe)Ni(μ-1SSS':2SS-tpdt)Ni(dppe)][PF6]2 (1[PF6]2, dppe = Ph2P(CH2)2PPh2), [(dppe)Ni(μ-1SSN:2SS-npdt)Ni(dppe)][PF6]2 (2[PF6]2) and [(dppe)Ni(t-Cl)(μ-1SSX:2SS-C4H8S2X)Ni(dppe)][PF6] (3[PF6], X = S; 4[PF6], X = O) were facilely obtained by the salt metathesis reaction. These four thiolate-bridged dinickel complexes have all been fully characterized by spectroscopic methods and X-ray crystallography. In 2[PF6]2, elongation of the Ni-N bond distance, possibly caused by steric hindrance, indicates that the pendant nitrogen group shuttles between the two nickel centers in solution, which is evidenced by 31P{1H} NMR spectroscopic results. Furthermore, these thiolate-bridged dinickel complexes have all been proved to be electrocatalysts for proton reduction to hydrogen. Notably, complex 2[PF6]2 featuring a pendant amine group in the secondary coordination sphere exhibits the best catalytic activity at a relatively low overpotential.
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Affiliation(s)
- Puhua Sun
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian, 116024, P.R. China.
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5
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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: 65] [Impact Index Per Article: 16.3] [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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6
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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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7
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Sitek P, Chmielowska A, Jaworska M, Lodowski P, Szczepańska M. Theoretical study of cobalt and nickel complexes involved in methyl transfer reactions: structures, redox potentials and methyl binding energies. Struct Chem 2019. [DOI: 10.1007/s11224-019-01384-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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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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9
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Zhang A, Raje S, Liu J, Li X, Angamuthu R, Tung CH, Wang W. Nickel-Mediated Stepwise Transformation of CO to Acetaldehyde and Ethanol. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ailing Zhang
- School
of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan 250100, China
| | - Sakthi Raje
- Laboratory
of Inorganic Synthesis and Bioinspired Catalysis (LISBIC), Department
of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Jianguo Liu
- School
of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan 250100, China
| | - Xiaoyan Li
- School
of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan 250100, China
| | - Raja Angamuthu
- Laboratory
of Inorganic Synthesis and Bioinspired Catalysis (LISBIC), Department
of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Chen-Ho Tung
- School
of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan 250100, China
| | - Wenguang Wang
- School
of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan 250100, China
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10
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Kure B, Sano M, Watanabe N, Nakajima T, Tanase T. Synthesis and Reactivity of Thiolate‐Bridged Ni
II
M
I
Heterodinuclear Complexes (M = Rh, Ir) with an S‐Bidentate NiP
2
S
2
Metalloligand. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Bunsho Kure
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
| | - Mikie Sano
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
| | - Natsuki Watanabe
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
| | - Takayuki Nakajima
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
| | - Tomoaki Tanase
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
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11
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Zhao T, Ghosh P, Martinez Z, Liu X, Meng X, Darensbourg MY. Discrete Air-Stable Nickel(II)–Palladium(II) Complexes as Catalysts for Suzuki–Miyaura Reactions. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tiankun Zhao
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Pokhraj Ghosh
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Zachary Martinez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Xufeng Liu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
- College
of Materials and Chemical Engineering, Ningbo University of Technology, Ningbo 315016, China
| | - Xianggao Meng
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, China
| | - Marcetta Y. Darensbourg
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
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12
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Kobayashi F, Ohtani R, Teraoka S, Kosaka W, Miyasaka H, Zhang Y, Lindoy LF, Hayami S, Nakamura M. Syntheses, structures and magnetic properties of tetranuclear cubane-type and heptanuclear wheel-type nickel(ii) complexes with 3-methoxysalicylic acid derivatives. Dalton Trans 2017. [DOI: 10.1039/c7dt01757j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Three mono- and multi-nuclear Ni(ii) compounds were synthesised and investigated.
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Affiliation(s)
- Fumiya Kobayashi
- Department of Chemistry
- Graduate School of Science and Technology
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Ryo Ohtani
- Department of Chemistry
- Graduate School of Science and Technology
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Saki Teraoka
- Department of Chemistry
- Graduate School of Science and Technology
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Wataru Kosaka
- Institute for Materials Research (IMR)
- Tohoku University
- Sendai 980-8577
- Japan
- Department of Chemistry
| | - Hitoshi Miyasaka
- Institute for Materials Research (IMR)
- Tohoku University
- Sendai 980-8577
- Japan
- Department of Chemistry
| | - Yingjie Zhang
- Australian Nuclear Science and Technology Organization
- Australia
| | | | - Shinya Hayami
- Department of Chemistry
- Graduate School of Science and Technology
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Masaaki Nakamura
- Department of Chemistry
- Graduate School of Science and Technology
- Kumamoto University
- Kumamoto 860-8555
- Japan
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13
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Chu X, Xu X, Su H, Raje S, Angamuthu R, Tung CH, Wang W. Heteronuclear assembly of Ni–Cu dithiolato complexes: synthesis, structures, and reactivity studies. Inorg Chem Front 2017. [DOI: 10.1039/c6qi00536e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A mild route was discovered to synthesize heterometallic [NiIICuI] complexes featuring square-planar Ni(ii) and distorted tetrahedral Cu(i).
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Affiliation(s)
- Xiaoxiao Chu
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
| | - Xin Xu
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
| | - Hao Su
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
| | - Sakthi Raje
- Laboratory of Inorganic Synthesis and Bioinspired Catalysis (LISBIC)
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Raja Angamuthu
- Laboratory of Inorganic Synthesis and Bioinspired Catalysis (LISBIC)
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan 250100
- PR China
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14
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Warner DS, Limberg C, Oldenburg FJ, Braun B. Reaction of a polydentate cysteine-based ligand and its nickel(ii) complex with electrophilic and nucleophilic methyl-transfer reagents - from S-methylation to acetyl coenzyme A synthase reactivity. Dalton Trans 2015; 44:18378-85. [PMID: 26390049 DOI: 10.1039/c5dt02828k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The L-cysteine derived N2S2 ligand precursor H2L and its nickel(ii) complex L2Ni2 were investigated with respect to their behaviour in contact with electrophilic and nucleophilic methylation reagents (H2L = (N,N'-dimethyl-(2R,5R)-bis-(sulfanylmethyl)-piperazine). Treatment of deprotonated L(2-) with MeI led to the selective methylation of the thiolate groups thus generating a novel potential ligand, Me2L, which is neutral and contains two thioether donors. The coordinating properties of Me2L were demonstrated by the synthesis of a first nickel(ii) complex: reaction with NiBr2 led to a mononuclear complex 2 where all donor atoms coordinate to the nickel ion, which completes its octahedral coordination sphere by the two bromide ligands. If, however, the complex [LNi]2 (1) is treated with MeI only one thiolate function per ligand moiety is methylated, while the other one remains a thiolate. This leads to [MeLNi](+) complex metal fragments, which trimerize including a μ3-bridging iodide ion to give the compound 3 that was tested with regards to ACS reactivity. While it behaved inert towards CO, attempts to replace the bridging iodide ligand by methyl units in reactions with nucleophilic methylation reagents led to a product, which could not be identified but reacted with CO. Work-up showed that this protocol had converted the thiolate function of MeL(-) into a thioester function, which corresponds to an ACS-like reactivity.
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Affiliation(s)
- D S Warner
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, 12489 Berlin, Germany.
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15
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Yadav S, Kumar S, Gupta R. Manganese Complexes of Pyrrole‐ and Indolecarboxamide Ligands: Synthesis, Structure, Electrochemistry, and Applications in Oxidative and Lewis‐Acid‐Assisted Catalysis. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500773] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sunil Yadav
- Department of Chemistry, University of Delhi, Delhi 110007, India, http://people.du.ac.in/~rgupta/
| | - Sushil Kumar
- Department of Chemistry, University of Delhi, Delhi 110007, India, http://people.du.ac.in/~rgupta/
| | - Rajeev Gupta
- Department of Chemistry, University of Delhi, Delhi 110007, India, http://people.du.ac.in/~rgupta/
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16
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Liu XF, Li X, Yan J. Synthetic and structural studies of the mononuclear nickel(II) ethanedithiolate complexes with chelating N-substituted bis(diphenylphosphanyl)amine. Polyhedron 2015. [DOI: 10.1016/j.poly.2014.09.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Liu XF. Condensation reactions of the mononuclear nickel(II) complexes [RN(PPh 2 ) 2 ]NiCl 2 with 1,2-ethanedithiol or 1,3-propanedithiol. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.05.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Kure B, Sano M, Nakajima T, Tanase T. Systematic Heterodinuclear Complexes with MM′(μ-meppp) Centers That Tune the Properties of a Nesting Hydride (M = Ni, Pd, Pt; M′ = Rh, Ir; H2meppp = meso-1,3-Bis[(mercaptoethyl)phenylphosphino]propane). Organometallics 2014. [DOI: 10.1021/om500410f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Bunsho Kure
- Department of Chemistry,
Faculty of Science, Nara Women’s University, Kitauoya-nishi-machi, Nara 630-8506, Japan
| | - Mikie Sano
- Department of Chemistry,
Faculty of Science, Nara Women’s University, Kitauoya-nishi-machi, Nara 630-8506, Japan
| | - Takayuki Nakajima
- Department of Chemistry,
Faculty of Science, Nara Women’s University, Kitauoya-nishi-machi, Nara 630-8506, Japan
| | - Tomoaki Tanase
- Department of Chemistry,
Faculty of Science, Nara Women’s University, Kitauoya-nishi-machi, Nara 630-8506, Japan
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19
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Can M, Armstrong F, Ragsdale SW. Structure, function, and mechanism of the nickel metalloenzymes, CO dehydrogenase, and acetyl-CoA synthase. Chem Rev 2014; 114:4149-74. [PMID: 24521136 PMCID: PMC4002135 DOI: 10.1021/cr400461p] [Citation(s) in RCA: 373] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Mehmet Can
- Department
of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Fraser
A. Armstrong
- Inorganic
Chemistry Laboratory, University of Oxford Oxford, OX1 3QR, United Kingdom
| | - Stephen W. Ragsdale
- Department
of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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20
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Chmielowska A, Lodowski P, Jaworska M. Redox Potentials and Protonation of the A-Cluster from Acetyl-CoA Synthase. A Density Functional Theory Study. J Phys Chem A 2013; 117:12484-96. [DOI: 10.1021/jp402616e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
| | - Piotr Lodowski
- Institute
of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland
| | - Maria Jaworska
- Institute
of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland
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21
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Shaw WJ. The Outer-Coordination Sphere: Incorporating Amino Acids and Peptides as Ligands for Homogeneous Catalysts to Mimic Enzyme Function. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING 2012. [DOI: 10.1080/01614940.2012.679453] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Abstract
Nickel-containing carbon monoxide dehydrogenases, acetyl-CoA synthases, nickel-iron hydrogenases, and diron hydrogenases are distinct metalloenzymes yet they share a number of important characteristics. All are O(2)-sensitive, with active-sites composed of iron and/or nickel ions coordinated primarily by sulfur ligands. In each case, two metals are juxtaposed at the "heart" of the active site, within range of forming metal-metal bonds. These active-site clusters exhibit multielectron redox abilities and must be reductively activated for catalysis. Reduction potentials are milder than expected based on formal oxidation state changes. When reductively activated, each cluster attacks an electrophilic substrate via an oxidative addition reaction. This affords a two-electron-reduced substrate bound to one or both metals of an oxidized cluster. M-M bonds have been established in hydrogenases where they serve to initiate the oxidative addition of protons and perhaps stabilize active sites in multiple redox states. The same may be true of the CODH and ACS active sites-Ni-Fe and Ni-Ni bonds in these sites may play critical roles in catalysis, stabilizing low-valence states and initiating oxidative addition of CO(2) and methyl group cations, respectively. In this article, the structural and functional commonalities of these metalloenzyme active sites are described, and the case is made for the formation and use of metal-metal bonds in each enzyme mentioned. As a post-script, the importance of Fe-Fe bonds in the nitrogenase FeMoco active site is discussed.
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Affiliation(s)
- Paul A Lindahl
- Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA.
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23
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Horn B, Limberg C, Herwig C, Mebs S. The conversion of nickel-bound CO into an acetyl thioester: organometallic chemistry relevant to the acetyl coenzyme A synthase active site. Angew Chem Int Ed Engl 2011; 50:12621-5. [PMID: 22065604 DOI: 10.1002/anie.201105281] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/02/2011] [Indexed: 11/06/2022]
Abstract
When three become one: Within one nickel-based model system, the three reactants CO, MeI, and PhSH have been assembled to yield an acetyl thioester. The reactivity is of relevance for the functioning of the acetyl coenzyme A synthase active site and provides insights into possible binding sequences.
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Affiliation(s)
- Bettina Horn
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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24
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Horn B, Limberg C, Herwig C, Mebs S. Die Umsetzung von nickelgebundenem CO zum Thioester: Organometallchemie mit Bezug zum aktiven Zentrum der Acetyl-Coenzym-A-Synthase. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201105281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Bender G, Pierce E, Hill JA, Darty JE, Ragsdale SW. Metal centers in the anaerobic microbial metabolism of CO and CO2. Metallomics 2011; 3:797-815. [PMID: 21647480 PMCID: PMC3964926 DOI: 10.1039/c1mt00042j] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Carbon dioxide and carbon monoxide are important components of the carbon cycle. Major research efforts are underway to develop better technologies to utilize the abundant greenhouse gas, CO(2), for harnessing 'green' energy and producing biofuels. One strategy is to convert CO(2) into CO, which has been valued for many years as a synthetic feedstock for major industrial processes. Living organisms are masters of CO(2) and CO chemistry and, here, we review the elegant ways that metalloenzymes catalyze reactions involving these simple compounds. After describing the chemical and physical properties of CO and CO(2), we shift focus to the enzymes and the metal clusters in their active sites that catalyze transformations of these two molecules. We cover how the metal centers on CO dehydrogenase catalyze the interconversion of CO and CO(2) and how pyruvate oxidoreductase, which contains thiamin pyrophosphate and multiple Fe(4)S(4) clusters, catalyzes the addition and elimination of CO(2) during intermediary metabolism. We also describe how the nickel center at the active site of acetyl-CoA synthase utilizes CO to generate the central metabolite, acetyl-CoA, as part of the Wood-Ljungdahl pathway, and how CO is channelled from the CO dehydrogenase to the acetyl-CoA synthase active site. We cover how the corrinoid iron-sulfur protein interacts with acetyl-CoA synthase. This protein uses vitamin B(12) and a Fe(4)S(4) cluster to catalyze a key methyltransferase reaction involving an organometallic methyl-Co(3+) intermediate. Studies of CO and CO(2) enzymology are of practical significance, and offer fundamental insights into important biochemical reactions involving metallocenters that act as nucleophiles to form organometallic intermediates and catalyze C-C and C-S bond formations.
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Affiliation(s)
- Güneş Bender
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Elizabeth Pierce
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Jeffrey A. Hill
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Joseph E. Darty
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Stephen W. Ragsdale
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
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26
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Zimmerman JR, Smucker BW, Dain RP, Vanstipdonk MJ, Eichhorn DM. Tridentate N(2)S ligand from 2,2'-dithiodibenzaldehyde and N,N-dimethylethylenediamine: Synthesis, structure, and characterization of a Ni(II) complex with relevance to Ni Superoxide Dismutase. Inorganica Chim Acta 2011; 373:54-61. [PMID: 21666847 PMCID: PMC3110705 DOI: 10.1016/j.ica.2011.03.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Nickel Superoxide Dismutase (NiSOD) and the A-cluster of Carbon Monoxide Dehydrogenase/Acetyl Coenzyme A Synthase (CODH/ACS) both feature active sites with Ni coordinated by thiolate and amide donors. It is likely that the particular set of donors is important in tuning the redox potential of the Ni center(s). We report herein an expansion of our efforts involving the use of 2,2'-dithiodibenzaldehyde (DTDB) as a synthon for metal-thiolate complexes to reactions with Ni complexes of N,N-dimethylethylenediamine (dmen). In the presence of coordinating counterions, these reactions result in monomeric square-planar complexes of the tridentate N(2)S donor ligand derived from the Schiff-base condensation of dmen and DTDB. In the absence of a coordinating counterion, we have isolated a Ni(II) complex with an asymmetric N(2)S(2) donor set involving one amine and one imine N donor in addition to two thiolate donors. This latter complex is discussed with respect to its relevance to the active site of NiSOD.
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Affiliation(s)
- Joshua R Zimmerman
- Department of Chemistry, Wichita State University, Wichita, KS 67260-0051
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Yoshinari N, Hashimoto Y, Igashira-Kamiyama A, Konno T. Synthesis, Characterization, and Crystal Structures of Cis and Trans Isomers of a Platinate(II) Complex with D-Penicillaminate. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2011. [DOI: 10.1246/bcsj.20110036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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28
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Jenkins RM, Pinder TA, Hatley ML, Reibenspies JH, Darensbourg MY. Tetradentate N2S2 Vanadyl(IV) Coordination Complexes: Synthesis, Characterization, and Reactivity Studies. Inorg Chem 2011; 50:1849-55. [DOI: 10.1021/ic1022533] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roxanne M. Jenkins
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Tiffany A. Pinder
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Michelle L. Hatley
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Joseph H. Reibenspies
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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29
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Herrick RS, Ziegler CJ, Gambella A. Reactions of [Re(CO)3]+ with Histidylhistidine and Modified Histidines. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201000532] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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30
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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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Matsumoto T, Ito M, Kotera M, Tatsumi K. A dinuclear nickel complex modeling of the Nid(ii)-Nip(i) state of the active site of acetyl CoA synthase. Dalton Trans 2010; 39:2995-7. [DOI: 10.1039/b924915j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Jenkins RM, Singleton ML, Almaraz E, Reibenspies JH, Darensbourg MY. Imidazole-containing (N3S)-Ni(II) complexes relating to nickel containing biomolecules. Inorg Chem 2009; 48:7280-93. [PMID: 19572492 PMCID: PMC2908898 DOI: 10.1021/ic900778k] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dimeric (N(2)S)Ni complexes and the monomeric N(2)S(2) bismercaptodiazacycloheptane nickel complex, (bme-dach)Ni, serve as precursors to two N(2)-, N'-/ S- complexes where N(2) = diazacycloheptane, N' = imidazole and S = thiolate. As rare examples of nickel complexes containing a mixed thiolate/imidazole ligand set, these complexes are characterized by X-ray diffraction, UV/vis, and variable temperature (1)H NMR spectroscopies, and electrochemistry. Density functional theory computations relate the orientation of the imidazole with respect to the N(2)N'SNi square plane to the VT NMR observed fluxionality and activation parameters. The superoxide dismutase activity of the imidazole complexes was investigated by the nitroblue tetrazolium assay.
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Affiliation(s)
- Roxanne M. Jenkins
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
| | | | - Elky Almaraz
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
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33
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Dinuclear nickel complexes modeling the structure and function of the acetyl CoA synthase active site. Proc Natl Acad Sci U S A 2009; 106:11862-6. [PMID: 19584250 DOI: 10.1073/pnas.0900433106] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A dinuclear nickel complex with methyl and thiolate ligands, Ni(dadt(Et))Ni(Me)(SDmp) (2), has been synthesized as a dinuclear Ni(d)-Ni(p)-site model of acetyl-CoA synthase (ACS) (dadt(Et) is N,N'-diethyl-3,7-diazanonane-1,9-dithiolate; Dmp is 2,6-dimesitylphenyl). Complex 2 was prepared via 2 methods: (i) ligand substitution of a dinuclear Ni(II)-Ni(II) cation complex [Ni(dadt(Et)) Ni(tmtu)2] (OTf)2 (1) with MeMgBr and KSDmp (tmtu is tetramethylthiourea), (ii) methyl transfer from methylcobaloxime Co(dmgBF2)2(Me)(Py) (5) to a Ni(II)-Ni(0) complex such as [Ni(dadt(Et))Ni(cod)] (3), generated in situ from Ni(dadt(Et)) and Ni(cod)(2), followed by addition of KSDmp (cod is 1,5-cyclooctadiene; dmgBF2 is difluoroboryl-dimethylglyoximate). Method ii models the formation of Nip-Me species proposed as a plausible intermediate in ACS catalysis. The reaction of 2 with excess CO affords the acetylthioester CH3C(O)SDmp (8) with concomitant formation of Ni(dadt(Et))Ni(CO)2 (9) and Ni(CO)4 plus Ni(dadt(Et)). When complex 2 is treated with 1 equiv of CO in the presence of excess 1,5-cyclooctadiene, the formation of 9 and Ni(CO)4 is considerably suppressed, and instead the dinuclear Ni(II)-Ni(0) complex is generated in situ, which further affords 2 upon successive treatment with Co(dmgBF2)2(Me)(Py) (5) and KSDmp. These results suggest that (i) ACS catalysis could include the Nid(II)-Nip(0) state as the active species, (ii) The Nid(II)-Nip(0) species could first react with methylcobalamin to afford Nid(II)-Nip(II)-Me, and (iii) CO insertion into the Nip-Me bond and the successive reductive elimination of acetyl-CoA occurs immediately when CoA is coordinated to the Nip site to form the active Nid(II)-Nip(0) species.
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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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35
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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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36
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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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38
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Green KN, Hess JL, Thomas CM, Darensbourg MY. Resin-bound models of the [FeFe]-hydrogenase enzyme active site and studies of their reactivity. Dalton Trans 2009:4344-50. [DOI: 10.1039/b823152d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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39
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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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Kulon K, Woźniak D, Wegner K, Grzonka Z, Kozłowski H. Specific interactions of metal ions with Cys-Xaa-Cys unit inserted into the peptide sequence. J Inorg Biochem 2007; 101:1699-706. [PMID: 17532049 DOI: 10.1016/j.jinorgbio.2007.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 03/30/2007] [Accepted: 04/03/2007] [Indexed: 11/18/2022]
Abstract
In this work five peptides with Cys-Xaa-Cys motif were studied including Ac-Cys-Gly-Cys-NH(2), Ac-Cys-Pro-Cys-Pro-NH(2), their N-unprotected analogues and the N-terminal fragment of metallothionein-3, Met-Asp-Pro-Glu-Thr-Cys-Pro-Cys-Pro-NH(2). All these peptides were found to be very effective ligands for Ni(2+), Zn(2+) and Cd(2+) ions. Potentiometric and spectroscopic (UV-Vis, CD and MCD) studies have proved that sulfur atoms are critical donors for the metal ions coordination. The amide nitrogen may participate in the metal ion binding only in the case when Gly is adjacent to Cys residues. Ac-Cys-Gly-Cys-NH(2) may serve as a low molecular weight model for cluster A, which is a binding unit of nickel ion in acetyl coenzyme A synthase. This bifunctional enzyme from anaerobic microorganisms catalyzes the formation of acetyl coenzyme A from CO, a methyl group donated by the corrinoid-iron-sulfur protein and coenzyme A. Other peptides studied in this work were Ac-Cys-Pro-Cys-Pro-NH(2) and Met-Asp-Pro-Glu-Thr-Cys-Pro-Cys-NH(2) originating from metallothionein sequence. These motifs are characteristic for the sequence of cysteine rich metallothionein-3 (MT-3) called also neuronal growth inhibitory factor (GIF). Cys-Pro-Cys-Pro fragment of protein was demonstrated to be crucial for the inhibitory activity of the protein.
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Affiliation(s)
- Kinga Kulon
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
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Desrochers PJ, Duong DS, Marshall AS, Lelievre SA, Hong B, Brown JR, Tarkka RM, Manion JM, Holman G, Merkert JW, Vicic DA. Nickel−Cysteine Binding Supported by Phosphine Chelates. Inorg Chem 2007; 46:9221-33. [PMID: 17854178 DOI: 10.1021/ic701150q] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The effect of chelating phosphines was tested on the structure and pH-dependent stability of nickel-cysteine binding. (1,2-Bis(diphenylphosphino)ethane (dppe) and 1,1,1-tris[(diphenylphosphino)methyl]ethane (triphos) were used with three different cysteine derivatives (L-cysteine, Cys; L-cysteine ethyl ester, CysEt; cystamine, CysAm) to prepare complexes of the form (dppe)NiCysR(n+) and (triphos)NiCysR(n+) (n = 0 for Cys; n = 1 for CysEt and CysAm). Similar 31P {1H} NMR spectra for all (dppe)NiCysRn+ confirmed their square-planar P2NiSN coordination spheres. The structure of [(dppe)NiCysAm]PF6 was also confirmed by single-crystal X-ray diffraction methods. The (triphos)NiCysAm+ and (triphos)NiCysEt+ complexes were fluxional at room temperature by 31P NMR. Upon cooling to -80 degrees C, all gave spectra consistent with a P2NiSN coordination sphere with the third phosphorus uncoordinated. Temperature-dependent 31P NMR spectra showed that a trans P-Ni-S pi interaction controlled the scrambling of the coordinated triphos. In aqueous media, (dppe)NiCys was protonated at pH approximately 4-5, leading to possible formation of a nickel-cysteinethiol and eventual cysteine loss at pH < 3. The importance of N-terminus cysteine in such complexes was demonstrated by preparing (dppe)NiCys-bead and trigonal-bipyramidal Tp*NiCys-bead complexes, where Cys-bead represents cysteine anchored to polystyrene synthesis beads and Tp*- = hydrotris(3,5-dimethylpyrazolyl)borate. Importantly, results with these heterogeneous systems demonstrated the selectivity of these nickel centers for cysteine over methionine and serine and most specifically for N-terminus cysteine. The role of Ni-S pi bonding in nickel-cysteine geometries will be discussed, including how these results suggest a mechanism for the movement of electron density from nickel onto the backbone of coordinated cysteine.
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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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Harrop TC, Olmstead MM, Mascharak PK. Synthetic analogues of the active site of the A-cluster of acetyl coenzyme A synthase/CO dehydrogenase: syntheses, structures, and reactions with CO. Inorg Chem 2007; 45:3424-36. [PMID: 16602803 PMCID: PMC4826277 DOI: 10.1021/ic0520465] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two metallosynthons, namely (Et4N)2[Ni(NpPepS)] (1) and (Et4N)2[Ni(PhPepS)] (2) containing carboxamido-N and thiolato-S as donors have been used to model the bimetallic M(p)-Ni(d) subsite of the A-cluster of the enzyme acetyl coenzyme A synthase/CO dehydrogenase. A series of sulfur-bridged Ni/Cu dinuclear and trinuclear complexes (3-10) have been synthesized to explore their redox properties and affinity of the metal centers toward CO. The structures of (Et4N)2[Ni(PhPepS)] (2), (Et4N)[Cu(neo)Ni(NpPepS)] x 0.5 Et2O x 0.5 H2O (3 x 0.5 Et2O x 0.5 H2O), (Et4N)[Cu(neo)Ni(PhPepS)] x H2O (4 x H2O), (Et4N)2[Ni{Ni(NpPepS)}2] x DMF (5 x DMF), (Et4N)2[Ni(DMF)2{Ni(NpPepS)}2] x 3 DMF (6 x 3 DMF), (Et4N)2[Ni(DMF)2{Ni(PhPepS)}2] (8), and [Ni(dppe)Ni(PhPepS)] x CH2Cl2 (10 x CH2Cl2) have been determined by crystallography. The Ni(d) mimics 1 and 2 resist reduction and exhibit no affinity toward CO. In contrast, the sulfur-bridged Ni center (designated Ni(C)) in the trinuclear models 5-8 are amenable to reduction and binds CO in the Ni(I) state. Also, the sulfur-bridged Ni(C) center can be removed from the trimers (5-8) by treatment with 1,10-phenanthroline much like the "labile Ni" from the enzyme. The dinuclear Ni-Ni models 9 and 10 resemble the Ni(p)-Ni(d) subsite of the A-cluster more closely, and only the modeled Ni(p) site of the dimers can be reduced. The Ni(I)-Ni(II) species display EPR spectra typical of a Ni(I) center in distorted trigonal bipyramidal and distorted tetrahedral geometries for 9(red) and 10(red), respectively. Both species bind CO, and the CO-adducts 9(red)-CO and 10(red)-CO display strong nu(co) at 2044 and 1997 cm(-1), respectively. The reduction of 10 is reversible. The CO-affinity of 10 in the reduced state and the nu(co) value of 10(red)-CO closely resemble the CO-bound reduced A-cluster (nu(co) = 1996 cm(-1)).
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Affiliation(s)
- Todd C. Harrop
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064
| | | | - Pradip K. Mascharak
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064
- (P. K. Mascharak), Fax: + 1-831-459-2935 Tel: + 1-831-459-4251
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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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45
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Green KN, James WD, Cantillo AV, Darensbourg MY. The acetyl CoA synthase paradigm for hybrid bio-organometallics: Quantitative measures for resin-bound Ni–Rh complexes. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2006.10.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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46
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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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47
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Bramlett MR, Stubna A, Tan X, Surovtsev IV, Münck E, Lindahl PA. Mössbauer and EPR study of recombinant acetyl-CoA synthase from Moorella thermoacetica. Biochemistry 2006; 45:8674-85. [PMID: 16834342 DOI: 10.1021/bi060003+] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mössbauer and EPR spectroscopies were used to study the electronic structure of the A-cluster from recombinant acetyl-CoA synthase (the alpha subunit of the alpha2beta2 acetyl-CoA synthase/CO dehydrogenase). Once activated with Ni, these subunits have properties mimicking those associated with the alpha2beta2 tetramer, including structural heterogeneities. The Fe4S4 portion of the A-cluster in oxidized, methylated, and acetylated states was in the 2+ core oxidation state. Upon reduction with dithionite or Ti3+ citrate, samples of Ni-activated alpha developed the ability to accept a methyl group. Corresponding Mössbauer spectra exhibited two populations of A-clusters; roughly, 70% contained [Fe4S4]1+ cubanes, while approximately 30% contained [Fe4S4]2+ cubanes, suggesting an extremely low [Fe4S4](1+/2+) reduction potential for the 30% portion (perhaps <-800 mV vs NHE). The same population ratio was observed when Ni-free unactivated alpha was used. The 70% fraction exhibited paramagnetic hyperfine structure in the absence of an applied magnetic field, excluding the possibility that it represents an [Fe4S4]1+ cluster coupled to a (proximal) Ni(p)1+. EPR spectra of dithionite-reduced, Ni-activated alpha exhibited features at g = 5.8 and g(ave) approximately 1.93, consistent with a physical mixture of {S = 3/2; S = 1/2} spin-states for A-clusters containing [Fe4S4]1+ clusters. Incubation of Ni-activated alpha with dithionite and CO converted 25% of alpha subunits into the S = 1/2 A(red)-CO state. Previous correlation of this state to functional A-clusters suggests that only the 30% fraction not reduced by dithionite or Ti3+ citrate represents functional A-clusters. Comparison of spin states in oxidized and methylated states suggests that two electrons are required for reductive activation, starting from the oxidized state containing Ni(p)2+. Refitting published activity-vs-potential data supports an n = 2 reductive activation. Enzyme starting in the methylated state exhibited catalytic activity in the absence of an external reductant, suggesting that the two electrons used in reductive activation are retained by the enzyme after each catalytic cycle and that the enzyme does not have to pass through the A(red)-CO state during catalysis. Taken together, our results suggest that a Ni(p)0 state may form upon reductive activation and reform after each catalytic cycle.
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Affiliation(s)
- Matthew R Bramlett
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
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48
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Stibrany RT, Fox S, Bharadwaj PK, Schugar HJ, Potenza JA. Structural and spectroscopic features of mono- and binuclear nickel(II) complexes with tetradentate N(amine)2S(thiolate)2 ligation. Inorg Chem 2006; 44:8234-42. [PMID: 16270960 DOI: 10.1021/ic050114h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three complexes containing Ni(II)N(amine)2S(thiolate)2 units have been prepared and characterized. Both (R,R)-N,N'-bis(1-carboxy-2-mercaptoethyl)-1,2-diaminoethane [(R,R)-1] and N,N'-bis(2-methyl-2-mercaptoprop-1-yl)-1,3-diamino-2,2-dimethylpropane (4) act as tetradentate S-N-N-S ligands to form complexes Ni((R,R)-1) and Ni4 with nearly planar cis-NiN2S2 units. The N-Ni-N and S-Ni-S angles differ significantly in the two complexes yet are very nearly supplementary. The 1,3-disubstituted cyclohexane species rac-N,N'-bis(2-mercapto-2-methylprop-1-yl)-1,3-cyclohexanediamine (6) behaves as a bis(bidentate-N,S) ligand to form an unexpectedly intense-blue dinickel complex (1S,3R,1'S,3'R)-7, which contains two trans-NiN2S2 units bridged by 1,3-disubstituted cyclohexane groups. The coordination geometry in (1S,3R,1'S,3'R)-7 is distorted 15 degrees toward tetrahedral, most likely as a result of steric crowding, suggested by several short contacts between the NiS2 units and both the cyclohexyl and gem-dimethyl groups of the N,S-chelate rings. The complexes exhibit rich UV-vis spectra, whose deconvoluted bands are now fully assigned, from low to high energy, as ligand field (LF), pi(S) --> Ni(II) ligand-to-metal charge transfer (LMCT), sigma(S) --> Ni(II) LMCT, sigma(N) --> Ni(II) LMCT, localized S, and S,N Rydberg transitions. The unusually intense LF absorptions shown by (1S,3R,1'S,3'R)-7 are thought to result from relaxation of the Laporte restriction arising from the 15 degrees tetrahedral twist.
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Affiliation(s)
- Robert T Stibrany
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, USA
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49
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Green KN, Jeffery SP, Reibenspies JH, Darensbourg MY. A Nickel Tripeptide as a Metallodithiolate Ligand Anchor for Resin-Bound Organometallics. J Am Chem Soc 2006; 128:6493-8. [PMID: 16683815 DOI: 10.1021/ja060876r] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular structure of the acetyl CoA synthase enzyme has clarified the role of individual nickel atoms in the dinickel active site which mediates C-C and C-S coupling reactions. The NiN2S2 portion of the biocatalyst (N2S2 = a cysteine-glycine-cysteine or CGC4- tripeptide ligand) serves as an S-donor ligand comparable to classical bidentate ligands operative in organometallic chemistry, ligating the second nickel which is redox and catalytically active. Inspired by this biological catalyst, the synthesis of NiN2S2 metalloligands, including the solid-phase synthesis of resin-bound Ni(CGC)2-, and sulfur-based derivatization with W(CO)5 and Rh(CO)2+ have been carried out. Through comparison to analogous well-characterized, solution-phase complexes, Attenuated Total Reflectance FTIR spectroscopy establishes the presence of unique heterobimetallic complexes, of the form [Ni(CGC)]M(CO)x, both in solution and immobilized on resin beads. This work provides the initial step toward exploitation of such an evolutionarily optimized nickel peptide as a solid support anchor for hybrid bioinorganic-organometallic catalysts.
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Affiliation(s)
- Kayla N Green
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA
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50
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Phelps AL, Rampersad MV, Fitch SB, Darensbourg MY, Darensbourg DJ. A Kinetic Study of the Ring-Opening Process in Tungsten Carbonyl Complexes Containing Hemilabile Metallodithiolate Ligands. Inorg Chem 2005; 45:119-26. [PMID: 16390047 DOI: 10.1021/ic051367d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of the metallodithiolate derivative of tungsten pentacarbonyl from the reaction of photogenerated W(CO)(5)THF and Ni-1 ((1,5-bis(2-mercapto-2-methylpropane)-1,5-diazacyclooctanato)nickel(II)) is described, along with its crystal structure. In N,N-dimethylformamide solution, the pentacarbonyl exists in equilibrium with its tetracarbonyl analogue and carbon monoxide. The pentacarbonyl complex stereoselectively loses cis carbonyl ligands, as is apparent from (13)CO-labeling studies, where the thus-formed tetracarbonyl tungsten complex resulting from chelate ring-closure is preferentially (13)CO-labeled among the two mutually trans CO groups. The kinetics of the addition of CO to the tetracarbonyl to afford the metal pentacarbonyl were monitored by means of in situ infrared spectroscopy in the nu(CO) region at CO pressures between 28 and 97 bar and temperatures over the range 45-60 degrees C. Under these conditions, there was no evidence for W-S bond cleavage in the pentacarbonyl complex with concomitant formation of W(CO)(6). These studies reveal that the tetracarbonyl complex and CO are only slightly unstable with respect to the formation of the pentacarbonyl complex, with an equilibrium constant at 50 degrees C of about 2.8 M(-1) or DeltaG degrees = -1.4 kJ/mol. The activation parameters determined for the ring-opening process (DeltaH = 89.1 kJ/mol and DeltaS = -37.2 J/mol.K) suggest a solvent-assisted concerted ring-opening mechanism.
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Affiliation(s)
- Andrea L Phelps
- Department of Chemistry, Texas A&M University, College Station, 77843, USA
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