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Yasir Khan H, Tabassum S, Arjmand F. Preparation and characterization of ionic metal-based anticancer formulations of the type [bis-DACH tolfenamate metal {Co(II), Cu(II) and Zn(II)}] complexes: Binding studies with ct-DNA/tRNA, cleavage and cytotoxic activity against chemoresistant cancer cells. Inorganica Chim Acta 2023; 558:121725. [DOI: 10.1016/j.ica.2023.121725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
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2
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Pérez AL, Kemmerer A, Zapata AJ, Sartoris R, Gonzalez PJ, Urteaga R, Baggio R, Suarez S, Ramos CA, Dalosto SD, Rizzi AC, Brondino CD. Synthesis, structure, and characterisation of a ferromagnetically coupled dinuclear complex containing Co(II) ions in a high spin configuration and thiodiacetate and phenanthroline as ligands and of a series of isomorphous heterodinuclear complexes containing different Co : Zn ratios. Dalton Trans 2023; 52:14595-14605. [PMID: 37786344 DOI: 10.1039/d3dt02115g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
We report the synthesis, crystal structure, and characterisation of a dinuclear Co(II) compound with thiodiacetate (tda) and phenanthroline (phen) as ligands (1), and of a series of metal complexes isomorphous to 1 with different Co : Zn ratios (2, 4 : 1; 3, 1 : 1; 4, 1 : 4; 5, 1 : 10). General characterisation methodologies and X-ray data showed that all the synthesised complexes are isomorphous to Zn(II) and Cu(II) analogues (CSD codes: DUHXEL and BEBQII). 1 consists of centrosymmetric Co(II) ion dimers in which the ions are 3.214 Å apart, linked by two μ-O bridges. Each cobalt atom is in a distorted octahedral environment of the N2O3S type. UV-vis spectra of 1 and 5 are in line with high spin (S = 3/2) Co(II) ions in octahedral coordination and indicate that the electronic structure of both Co(II) ions in the dinuclear unit does not significantly change relative to that of the magnetically isolated Co(II) ion. EPR spectra of powder samples of 5 (Co : Zn ratio of 1 : 10) together with spectral simulation indicated high spin Co(II) ions with high rhombic distortion of the zfs [E/D = 0.31(1), D > 0]. DC magnetic susceptibility experiments on 1 and analysis of the data constraining the E/D value obtained by EPR yielded g = 2.595(7), |D| = 61(1) cm-1, and an intradimer ferromagnetic exchange coupling of J = 1.39(4) cm-1. EPR spectra as a function of Co : Zn ratio for both powder and single crystal samples confirmed that they result from two effective S' = 1/2 spins that interact through dipolar and isotropic exchange interactions to yield magnetically isolated S' = 1 centres and that interdimeric exchange interactions, putatively mediated by hydrophobic interactions between phen moieties, are negligible. The latter observation contrasts with that observed in the Cu(II) analogue, where a transition from S = 1 to S' = 1/2 was observed. Computational calculations indicated that the absence of the interdimeric exchange interaction in 1 is due to a lower Co(II) ion spin density delocalisation towards the metal ligands.
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Affiliation(s)
- Ana L Pérez
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
- Instituto de Física del Litoral, Universidad Nacional del Litoral - CONICET, Güemes 3450, 3000 Santa Fe, Argentina
| | - Axel Kemmerer
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Alejandro J Zapata
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Rosana Sartoris
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Pablo J Gonzalez
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Raul Urteaga
- Instituto de Física del Litoral, Universidad Nacional del Litoral - CONICET, Güemes 3450, 3000 Santa Fe, Argentina
- Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina
| | - Ricardo Baggio
- Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina
| | - Sebastián Suarez
- Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina
| | - Carlos A Ramos
- Instituto de Nanociencia y Nanotecnología, CNEA-CONICET, Centro Atómico Bariloche, 8400, San Carlos de Bariloche, Río Negro, Argentina
| | - Sergio D Dalosto
- Instituto de Física del Litoral, Universidad Nacional del Litoral - CONICET, Güemes 3450, 3000 Santa Fe, Argentina
- Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina
| | - Alberto C Rizzi
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Carlos D Brondino
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
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Devkota L, SantaLucia DJ, Wheaton AM, Pienkos AJ, Lindeman SV, Krzystek J, Ozerov M, Berry JF, Telser J, Fiedler AT. Spectroscopic and Magnetic Studies of Co(II) Scorpionate Complexes: Is There a Halide Effect on Magnetic Anisotropy? Inorg Chem 2023; 62:5984-6002. [PMID: 37000941 DOI: 10.1021/acs.inorgchem.2c04468] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
The observation of single-molecule magnetism in transition-metal complexes relies on the phenomenon of zero-field splitting (ZFS), which arises from the interplay of spin-orbit coupling (SOC) with ligand-field-induced symmetry lowering. Previous studies have demonstrated that the magnitude of ZFS in complexes with 3d metal ions is sometimes enhanced through coordination with heavy halide ligands (Br and I) that possess large free-atom SOC constants. In this study, we systematically probe this "heavy-atom effect" in high-spin cobalt(II)-halide complexes supported by substituted hydrotris(pyrazol-1-yl)borate ligands (TptBu,Me and TpPh,Me). Two series of complexes were prepared: [CoIIX(TptBu,Me)] (1-X; X = F, Cl, Br, and I) and [CoIIX(TpPh,Me)(HpzPh,Me)] (2-X; X = Cl, Br, and I), where HpzPh,Me is a monodentate pyrazole ligand. Examination with dc magnetometry, high-frequency and -field electron paramagnetic resonance, and far-infrared magnetic spectroscopy yielded axial (D) and rhombic (E) ZFS parameters for each complex. With the exception of 1-F, complexes in the four-coordinate 1-X series exhibit positive D-values between 10 and 13 cm-1, with no dependence on halide size. The five-coordinate 2-X series exhibit large and negative D-values between -60 and -90 cm-1. Interpretation of the magnetic parameters with the aid of ligand-field theory and ab initio calculations elucidated the roles of molecular geometry, ligand-field effects, and metal-ligand covalency in controlling the magnitude of ZFS in cobalt-halide complexes.
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Tiede ER, Heckman MT, Brennessel WW, Kraft BM. Chelation Equilibria and π-Electron Delocalization in Neutral Hypercoordinate Organosilicon Complexes of Pyrithione. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Erin R. Tiede
- Department of Chemistry, St. John Fisher University, Rochester, New York 14618, United States
| | - Matthew T. Heckman
- Department of Chemistry, St. John Fisher University, Rochester, New York 14618, United States
| | - William W. Brennessel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Bradley M. Kraft
- Department of Chemistry, St. John Fisher University, Rochester, New York 14618, United States
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5
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Kumar P, Devkota L, Casey MC, Fischer AA, Lindeman SV, Fiedler AT. Reversible Dioxygen Binding to Co(II) Complexes with Noninnocent Ligands. Inorg Chem 2022; 61:16664-16677. [PMID: 36206536 PMCID: PMC11218047 DOI: 10.1021/acs.inorgchem.2c02246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of mononuclear Co(II) complexes with noninnocent (redox-active) ligands are prepared that exhibit metal-ligand cooperativity during the reversible binding of O2. The complexes have the general formula, [CoII(LS,N)(TpR2)] (R = Me, Ph), where LS,N is a bidentate o-aminothiophenolate and TpR2 is a hydrotris(pyrazol-1-yl)borate scorpionate with R-substituents at the 3- and 5-positions. Exposure to O2 at room temperature results in one-electron oxidation and deprotonation of LS,N. The oxidized derivatives possess substantial "singlet diradical" character arising from antiferromagnetic coupling between an iminothiosemiquinonate (ITSQ•-) ligand radical and a low-spin Co(II) ion. The [CoII(TpMe2)(X2ITSQ)] complexes, where X = H or tBu, coordinate O2 reversibly at reduced temperatures to provide Co/O2 adducts. The O2 binding reactions closely resemble those previously reported by our group (Kumar et al., J. Am. Chem. Soc. 2019,141, 10984-10987) for the related complexes [CoII(TpMe2)(tBu2SQ)] and [CoII(TpMe2)(tBu2ISQ)], where tBu2(I)SQ represents 4,6-di-tert-butyl-(2-imino)semiquinonate radicals. In each case, the oxygenation reaction proceeds via the addition of O2 to both the cobalt ion and the ligand radical, generating metallocyclic cobalt(III)-alkylperoxo structures. Thermodynamic measurements elucidate the relationship between O2 affinity and redox potentials of the (imino)(thio)semiquinonate radicals, as well as energetic differences between these reactions and conventional metal-based oxygenations. The results highlight the utility and versatility of noninnocent ligands in the design of O2-absorbing compounds.
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Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Laxmi Devkota
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Maximilian C Casey
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Anne A Fischer
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Sergey V Lindeman
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Adam T Fiedler
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
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6
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Varghese A, Chaturvedi SS, DiCastri B, Mehler E, Fields GB, Karabencheva-Christova TG. Effects of the Nature of the Metal Ion, Protein and Substrate on the Catalytic Center in Matrix Metalloproteinase-1: Insights from Multilevel MD, QM/MM and QM Studies. Chemphyschem 2021; 23:10.1002/cphc.202100680. [PMID: 35991515 PMCID: PMC9387770 DOI: 10.1002/cphc.202100680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Indexed: 11/06/2022]
Abstract
Matrix metalloproteinase-1 (MMP-1) is a Zn(II) dependent endopeptidase involved in the degradation of collagen, the most abundant structural protein in the extracellular matrix of connective tissues and the human body. Herein we performed a multilevel computational analysis including molecular dynamics (MD), combined quantum mechanics/molecular mechanics (QM/MM), and quantum mechanics (QM) calculations to characterize the structure and geometry of the catalytic Zn(II) within the MMP-1 protein environment in comparison to crystallographic and spectroscopic data. The substrate's removal fine-tuned impact on the conformational dynamics and geometry of the catalytic Zn(II) center was also explored. Finally, the study examined the effect of substituting catalytic Zn(II) by Co(II) on the overall structure and dynamics of the MMP-1 THP complex and specifically on the geometry of the catalytic metal center. Overall our QM/MM and QM studies were in good agreement with the MM description of the Zn(II) centers in the MD simulations.
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Affiliation(s)
- Ann Varghese
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931
| | - Shobhit S Chaturvedi
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931
| | - Bella DiCastri
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931
| | - Emerald Mehler
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931
| | - Gregg B Fields
- Department of Chemistry and Biochemistry and I-HEALTH, Florida Atlantic University, Jupiter, Florida 33458
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7
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Seo H, Prosser KE, Kalaj M, Karges J, Dick BL, Cohen SM. Evaluating Metal-Ligand Interactions of Metal-Binding Isosteres Using Model Complexes. Inorg Chem 2021; 60:17161-17172. [PMID: 34699201 DOI: 10.1021/acs.inorgchem.1c02433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bioisosteres are a useful approach to address pharmacokinetic liabilities and improve drug-like properties. Specific to developing metalloenzyme inhibitors, metal-binding pharmacophores (MBPs) have been combined with bioisosteres, to produce metal-binding isosteres (MBIs) as alternative scaffolds for use in fragment-based drug discovery (FBDD). Picolinic acid MBIs have been reported and evaluated for their metal-binding ability, pharmacokinetic properties, and enzyme inhibitory activity. However, their structural, electronic, and spectroscopic properties with metal ions other than Zn(II) have not been reported, which might reveal similarities and differences between MBIs and the parent MBPs. To this end, [M(TPA)(MBI)]+ (M = Ni(II) and Co(II), TPA = tris(2-pyridylmethyl)amine) is presented as a bioinorganic model system for investigating picolinic acid, four heterocyclic MBIs, and 2,2'-bipyridine. These complexes were characterized by X-ray crystallography as well as NMR, IR, and UV-vis spectroscopies, and their magnetic moments were accessed. In addition, [(TpPh,Me)Co(MBI)] (TpPh,Me = hydrotris(3,5-phenylmethylpyrazolyl)borate) was used as a second model compound, and the limitations and attributes of the two model systems are discussed. These results demonstrate that bioinorganic model complexes are versatile tools for metalloenzyme inhibitor design and can provide insights into the broader use of MBIs.
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Affiliation(s)
- Hyeonglim Seo
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Kathleen E Prosser
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Mark Kalaj
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Johannes Karges
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Benjamin L Dick
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Seth M Cohen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
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8
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Direm A, El Bali B, Sayin K, Abdelbaky MS, García-Granda S. Experimental and in silico studies of dichloro-tetrakis(1H-pyrazole)-cobalt(II): Structural description, photoluminescent behavior and molecular docking. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Tolan DA, Kashar TI, Yoshizawa K, El‐Nahas AM. Synthesis, spectral characterization, density functional theory studies, and biological screening of some transition metal complexes of a novel hydrazide–hydrazone ligand of isonicotinic acid. Appl Organomet Chem 2021. [DOI: 10.1002/aoc.6205] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Dina A. Tolan
- Department of Chemistry College of Science and Humanities Prince Sattam bin Abdulaziz University Al‐Kharj 11942 Saudi Arabia
- Chemistry Department, Faculty of Science Menoufia University Shebin El‐Kom 13829 Egypt
| | - Tahani I. Kashar
- Chemistry Department, Faculty of Science Menoufia University Shebin El‐Kom 13829 Egypt
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering Kyushu University Fukuoka 819‐0395 Japan
| | - Ahmed M. El‐Nahas
- Chemistry Department, Faculty of Science Menoufia University Shebin El‐Kom 13829 Egypt
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10
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Kumar P, SantaLucia DJ, Kaniewska-Laskowska K, Lindeman SV, Ozarowski A, Krzystek J, Ozerov M, Telser J, Berry JF, Fiedler AT. Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands. Inorg Chem 2020; 59:16178-16193. [DOI: 10.1021/acs.inorgchem.0c01812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Daniel J. SantaLucia
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Kinga Kaniewska-Laskowska
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Gdańsk PL-80-233, Poland
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - John F. Berry
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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11
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Evaluation of cytotoxic activity and genotoxicity of structurally well characterized potent cobalt(II) phen–based antitumor drug entities: An in vitro and in vivo approach. Bioorg Chem 2019; 88:102963. [PMID: 31071506 DOI: 10.1016/j.bioorg.2019.102963] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/25/2019] [Accepted: 04/28/2019] [Indexed: 02/07/2023]
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12
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Kluska K, Adamczyk J, Krężel A. Metal binding properties of zinc fingers with a naturally altered metal binding site. Metallomics 2019; 10:248-263. [PMID: 29230465 DOI: 10.1039/c7mt00256d] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Zinc fingers (ZFs) are among the most abundant motifs found in proteins, and are commonly known for their structural role. Classical ZFs (CCHH) are part of the transcription factors that participate in DNA binding. Although biochemical studies of classical ZFs have a long history, there is limited knowledge about the sequential and structural diversity of ZFs. We have found that classical ZFs, with metal binding sites consisting of amino acids other than conserved Cys or His residues, are frequently encoded in the human genome, and we refer to these peptides as ZFs with a naturally altered metal binding site. The biological role of the altered ZFs remains undiscovered. In this study, we characterized nine natural XCHH, CXHH, CCXH and CCHX ZFs in terms of their Zn(ii) and Co(ii) binding properties, such as complex stoichiometry, spectroscopic properties and metal-to-peptide affinity. We revealed that XCHH and CXHH ZFs form ML complexes that are 4-5 orders of magnitude weaker in comparison to CCHH ZFs. Nevertheless, spectroscopic studies demonstrate that, depending on the altered position, they may adopt an open coordination geometry with one or two water molecules bound to a central metal ion, which has not been demonstrated in natural ZFs before. Stability data show that both CCXH and CCHX peptides have high Zn(ii) affinity (with a Kd of 10-9 to 10-11 M), suggesting their potential biological function. This study is a comprehensive overview of the relationship between the sequence, structure, and stability of ZFs.
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Affiliation(s)
- Katarzyna Kluska
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland.
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Khan HY, Zehra S, Parveen S, Yousuf I, Tabassum S, Arjmand F. New Ionic Cu(II) and Co(II) DACH–Flufenamate Conjugate Complexes: Spectroscopic Characterization, Single X–Ray Studies and Cytotoxic Activity on Human Cancer Cell Lines. ChemistrySelect 2018. [DOI: 10.1002/slct.201802698] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Huzaifa Yasir Khan
- Department of ChemistryAligarh Muslim University Aligarh 202002, Uttar Pradesh India
| | - Siffeen Zehra
- Department of ChemistryAligarh Muslim University Aligarh 202002, Uttar Pradesh India
| | - Sabiha Parveen
- Department of ChemistryAligarh Muslim University Aligarh 202002, Uttar Pradesh India
| | - Imtiyaz Yousuf
- Department of ChemistryAligarh Muslim University Aligarh 202002, Uttar Pradesh India
| | - Sartaj Tabassum
- Department of ChemistryAligarh Muslim University Aligarh 202002, Uttar Pradesh India
| | - Farukh Arjmand
- Department of ChemistryAligarh Muslim University Aligarh 202002, Uttar Pradesh India
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14
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Reinig RR, Fought EL, Ellern A, Windus TL, Sadow AD. Cobalt(ii) acyl intermediates in carbon-carbon bond formation and oxygenation. Dalton Trans 2018; 47:12147-12161. [PMID: 30090898 DOI: 10.1039/c8dt02661k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The organocobalt scorpionate compounds ToMCoR (ToM = tris(4,4-dimethyl-2-oxazolinyl)phenylborate; R = Bn, 1; CH2SiMe3, 2; Ph, 3; Et, 4; nBu, 5; Me, 6) react in carbonylation, oxidation, and carboxylation reactions via pathways that are distinctly influenced by the nature of the organometallic moiety. The compounds are prepared by reaction of ToMCoCl with the corresponding organolithium or organopotassium reagents. Compounds 1-6 were characterized by 8-line hyperfine coupling to cobalt in EPR spectra and solution phase magnetic measurements (μeff = 4-5μB) as containing a high-spin cobalt(ii) center. The UV-Vis spectra revealed an intense diagnostic band at ca. 700 nm (ε > 1000 M-1 cm-1) associated with the tetrahedral organocobalt(ii) center that was assigned to a d ← d transition on the basis of configuration interaction (CI) calculations. Complexes 1-6 react rapidly with CO to form equilibrating mixtures of the low spin organocobalt carbonyl ToMCo(R)CO, acyl ToMCoC([double bond, length as m-dash]O)R, and acyl carbonyl ToMCo{C([double bond, length as m-dash]O)R}CO. The 1H and 11B NMR spectra contained only one set of signals for the CO-treated solutions, whereas the solution-phase IR spectra contained up to two νCO and three νC([double bond, length as m-dash]O)R signals with intensities varying depending on the R group (R = Bn, 7; CH2SiMe3, 8; Ph, 9; Et, 10; nBu, 11; Me, 12). Single crystal X-ray diffraction of ToMCo{C([double bond, length as m-dash]O)Et}CO (10) supports its assignment as a square pyramidal cobalt(ii) acyl carbonyl complex. Upon evaporation of volatiles, solutions of 8-12 revert to the CO-free organocobalt starting materials 2-6, whereas attempts to isolate benzyl-derived 7 provide an unusual α-alkoxyketone species, characterized by single crystal X-ray diffraction. Despite the differences observed in the carbonylation of 1-6 as a result of varying the R group, compounds 7-12 all react rapidly with O2 through an oxygenation pathway to afford the corresponding carboxylate compounds ToMCoO2CR (R = Bn, 13; CH2SiMe3, 14; Ph, 15; Et, 16; nBu, 17; Me, 18). In contrast, the insertion of CO2 into the Co-C bond in 1-6 requires several days to weeks.
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Affiliation(s)
- Regina R Reinig
- US Department of Energy Ames Laboratory and Department of Chemistry, 1605 Gilman Hall, Iowa State University, Ames, IA 50011, USA.
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15
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Fischer AA, Lindeman SV, Fiedler AT. Spectroscopic and computational studies of reversible O2 binding by a cobalt complex of relevance to cysteine dioxygenase. Dalton Trans 2017; 46:13229-13241. [DOI: 10.1039/c7dt01600j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Spectroscopic and computational studies of reversible O2 binding by a cobalt active-site mimic shed light on the catalytic mechanism of cysteine dioxygenases.
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Marts AR, Kaine JC, Baum RR, Clayton VL, Bennett JR, Cordonnier LJ, McCarrick R, Hasheminasab A, Crandall LA, Ziegler CJ, Tierney DL. Paramagnetic Resonance of Cobalt(II) Trispyrazolylmethanes and Counterion Association. Inorg Chem 2016; 56:618-626. [PMID: 27977149 DOI: 10.1021/acs.inorgchem.6b02520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Paramagnetic resonance studies (EPR, ESEEM, ENDOR, and NMR) of a series of cobalt(II) bis-trispyrazolylmethane tetrafluoroborates are presented. The complexes studied include the parent, unsubstituted ligand (Tpm), two pyrazole-substituted derivatives (4Me and 3,5-diMe), and tris(1-pyrazolyl)ethane (Tpe), which includes a methyl group on the apical carbon atom. NMR and ENDOR establish the magnitude of 1H hyperfine couplings, while ESEEM provides information on the coordinated 14N. The data show that the pyrazole 3-position is more electron rich in the Tpm analogues, that the geometry about the apical atom influences the magnetic resonance, and that apical atom geometry appears more fixed in Tpm than in Tp. NMR and ENDOR establish that the BF4- counterion remains associated in fluid solution. In the case of the Tpm3,5Me complex, it appears to associate in solution, in the same position it occupies in the X-ray structure.
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Affiliation(s)
- Amy R Marts
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Joshua C Kaine
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Robert R Baum
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Vivien L Clayton
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Jami R Bennett
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Laura J Cordonnier
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Robert McCarrick
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Abed Hasheminasab
- Department of Chemistry, University of Akron , Akron, Ohio 44325, United States
| | - Laura A Crandall
- Department of Chemistry, University of Akron , Akron, Ohio 44325, United States
| | | | - David L Tierney
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
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17
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Fliedel C, Rosa V, Vileno B, Parizel N, Choua S, Gourlaouen C, Rosa P, Turek P, Braunstein P. Zwitterionic Cobalt Complexes with Bis(diphenylphosphino)(N-thioether)amine Assembling Ligands: Structural, EPR, Magnetic, and Computational Studies. Inorg Chem 2016; 55:4183-98. [PMID: 27054464 DOI: 10.1021/acs.inorgchem.5b02889] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The coordination of two heterofunctional P,P,S ligands of the N-functionalized DPPA-type bearing an alkylthioether or arylthioether N-substituent, (Ph2P)2N(CH2)3SMe (1) and (Ph2P)2N(p-C6H4)SMe (2), respectively, toward cobalt dichloride was investigated to examine the influence of the linker between the PNP nitrogen and the S atoms. The complexes [CoCl2(1)]2 (3) and [CoCl2(2)]2 (4) have been isolated, and 3 was shown by X-ray diffraction to be a unique dinuclear, zwitterion containing one CoCl moiety bis-chelated by two ligands 1 and one CoCl3 fragment coordinated by the S atom of a thioether function. The FT-IR, UV-vis, and EPR spectroscopic features of 3 were analyzed as the superposition of those of constitutive fragments identified by a retrosynthetic-type analysis. A similar approach provided insight into the nature of 4 for which no X-ray diffraction data could be obtained. A comparison between the spectroscopic features of 4 and of its constitutive fragments, [CoCl(2)2]PF6 (7) and [H2']2[CoCl4] (8) (2' = NH2(p-C6H4)SMe), and between those of 4 and 3 suggested that 4 could either have a zwitterionic structure, similar to that of 3, or contain a tetrahedral dicationic bis-chelated Co center associated with a CoCl4 dianion. Magnetic and EPR studies and theoretical calculations were performed. Doublet spin states were found for the pentacoordinated complexes [CoCl(1)2]PF6 (5) and 7 and anisotropic quadruplet spin states for the tetrahedral complexes [CoCl3(H1')] (6) (1' = NH2(CH2)3SMe) and 8. A very similar behavior was observed for 3 and 4, consisting in the juxtaposition of noninteracting doublet and quadruplet spin states. Antiferromagnetic interactions explain the formation of dimers for 6 and of layers for 8. The EPR signatures of 3 and 4 correspond to the superposition of low-spin nuclei in 5 and 7 and high-spin nuclei in 6 and 8, respectively. From DFT calculations, the solid-state structure of 4 appears best described as zwitterionic, with a low-spin state for the Co1 atom.
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Affiliation(s)
| | | | - Bertrand Vileno
- French EPR Federation of Research (REseau NAtional de Rpe interDisciplinaire, RENARD), Fédération IR-RPE CNRS 3443, 67081 Strasbourg, France
| | | | | | | | - Patrick Rosa
- CNRS, Université de Bordeaux, ICMCB , UPR9048, F-33600 Pessac, France
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18
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Baum RR, Myers WK, Greer SM, Breece RM, Tierney DL. The Original CoII Heteroscorpionates Revisited: On the EPR of Pseudotetrahedral CoII. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201501356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Robert R. Baum
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - William K. Myers
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - Samuel M. Greer
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - Robert M. Breece
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - David L. Tierney
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
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19
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Schofield JA, Brennessel WW, Urnezius E, Rokhsana D, Boshart MD, Juers DH, Holland PL, Machonkin TE. Metal-Halogen Secondary Bonding in a 2,5-Dichlorohydroquinonate Cobalt(II) Complex: Insight into Substrate Coordination in the Chlorohydroquinone Dioxygenase PcpA. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Yang H, Makaroff K, Paz N, Aitha M, Crowder MW, Tierney DL. Metal Ion Dependence of the Matrix Metalloproteinase-1 Mechanism. Biochemistry 2015; 54:3631-9. [PMID: 26018933 DOI: 10.1021/acs.biochem.5b00379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Matrix metalloproteinase-1 (MMP-1) plays crucial roles in disease-related physiologies and pathological processes in the human body. We report here solution studies of MMP-1, including characterization of a series of mutants designed to bind metal in either the catalytic site or the structural site (but not both). Circular dichroism and fluorescence spectroscopy of the mutants demonstrate the importance of the structural Zn(II) in maintaining both secondary and tertiary structure, while UV-visible, nuclear magnetic resonance, electron paramagnetic resonance, and extended X-ray absorption fine structure show its presence influences the catalytic metal ion's coordination number. The mutants allow us to demonstrate convincingly the preparation of a mixed-metal analogue, Co(C)Zn(S)-MMP-1, with Zn(II) in the structural site and Co(II) in the catalytic site. Stopped-flow fluorescence of the native form, Zn(C)Zn(S)-MMP-1, and the mixed-metal Co(C)Zn(S)-MMP-1 analogue shows that the internal fluorescence of a nearby Trp residue is modulated with catalysis and can be used to monitor reactivity under a number of conditions, opening the door to substrate profiling.
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Affiliation(s)
- Hao Yang
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Katherine Makaroff
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Nicholas Paz
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Mahesh Aitha
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Michael W Crowder
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - David L Tierney
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
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21
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Lacy DC, Roberts GM, Peters JC. The cobalt hydride that never was: revisiting Schrauzer's "hydridocobaloxime". J Am Chem Soc 2015; 137:4860-4. [PMID: 25798900 DOI: 10.1021/jacs.5b01838] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular cobalt-dmg (dmg = dimethylglyoxime) complexes are an important class of electrocatalysts used heavily in mechanistic model studies of the hydrogen evolution reaction (HER). Schrauzer's early isolation of a phosphine-stabilized "[H-Co(III)(dmgH)2P(nBu)3]" complex has long provided circumstantial support for the plausible intermediacy of Co(III)-H species in HER by cobaloximes in solution. Our investigation of this complex has led to a reassignment of its structure as [Co(II)(dmgH)2P(nBu)3], a complex that contains no hydride ligand and dimerizes to form an unsupported Co-Co bond in the solid state. A paramagnetic S = 3/2 impurity that forms during the synthesis of [Co(II)(dmgH)2P(nBu)3] when exposed to adventitious oxygen has also been characterized. This impurity features a (1)H NMR resonance at -5.06 ppm that was recently but erroneously attributed to the hydride resonance of "[H-Co(III)(dmgH)2P(nBu)3]". We draw attention to this reassignment because of its relevance to cobaloxime hydrides and HER catalysis and because Schrauzer's "hydridocobaloxime" is often cited as the primary example of a bona fide hydride that can be isolated and characterized on this widely studied HER platform.
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Affiliation(s)
- David C Lacy
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Gerri M Roberts
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jonas C Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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22
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Das M, Harms K, Ghosh BN, Rissanen K, Chattopadhyay S. Bis(μ-tetrazolato-NN′) bridged dinuclear nickel(II) Schiff base complexes: Tandem synthesis, structure and self assembly. Polyhedron 2015. [DOI: 10.1016/j.poly.2014.11.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Deb T, Anderson CM, Ma H, Petersen JL, Young VG, Jensen MP. Scorpionato Halide Complexes [(Tp
Ph,Me
)Ni–X] [X = Cl, Br, I; Tp
Ph,Me
= Hydrotris(3‐phenyl‐5‐methyl‐1‐pyrazolyl)borate]: Structures, Spectroscopy, and Pyrazole Adducts. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402897] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tapash Deb
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
| | - Caitlin M. Anderson
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
| | - Huaibo Ma
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, U.S.A
| | - Victor G. Young
- X‐ray Crystallographic Laboratory, Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, U.S.A
| | - Michael P. Jensen
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
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24
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Adamczyk J, Bal W, Krężel A. Coordination properties of dithiobutylamine (DTBA), a newly introduced protein disulfide reducing agent. Inorg Chem 2014; 54:596-606. [PMID: 25531180 DOI: 10.1021/ic5025026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The acid-base properties and metal-binding abilities of (2S)-2-amino-1,4-dimercaptobutane, otherwise termed dithiobutylamine (DTBA), which is a newly introduced reagent useful for reducing protein and peptide disulfides, were studied in solution using potentiometry, (1)H NMR spectroscopy, spectropolarimetry, and UV-vis spectroscopy. The list of metal ions studied here includes Zn(II), Cd(II), Ni(II), Co(II), and Cu(I). We found that DTBA forms specific and very stable polynuclear and mononuclear complexes with all of these metal ions using both of its sulfur donors. DTBA forms complexes more stable than those of the commonly used disulfide reducing agent DTT, giving it more interference capacity in studies of metal binding in thiol-containing biomolecules. The ability of DTBA to strongly bind metal ions is reflected in its limited properties as a thiol protectant in their presence, which is manifested through slower disulfide reduction kinetics. We found that this effect correlated with the stabilities of the complexes. Additionally, the reducing properties of DTBA toward MMTS-modified papain (MMTS = S-methylmethanethiosulfonate) were also significantly affected by the investigated metal ions. In this case, however, electrostatic interactions and stereospecific effects, rather than metal-binding abilities, were found to be responsible for the reduced protective properties of DTBA. Despite its limitations, a high affinity toward metal ions makes DTBA an attractive agent in competition studies with metalloproteins.
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Affiliation(s)
- Justyna Adamczyk
- Laboratory of Chemical Biology, Faculty of Biotechnology, University of Wroclaw , Joliot-Curie 14a, 50-383 Wroclaw, Poland
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25
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Mutule I, Borovika D, Rozenberga E, Romanchikova N, Zalubovskis R, Shestakova I, Trapencieris P. 5-membered cyclic hydroxamic acids as HDAC inhibitors. J Enzyme Inhib Med Chem 2014; 30:216-23. [PMID: 24939099 DOI: 10.3109/14756366.2014.912214] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The new histone deacylases inhibitors (HDACi) were synthesized in the class of 5-membered cyclic hydroxamic acids (5-CHA), showing medium size CHA as a new Zn-binding group. New reaction sequence was proposed for the synthesis of 5-membered alkylidene-cyclic-hydroxamic acids starting from butyrolactone. Compound 10c showed low µM activity on HeLa cell extracts. From these results, cyclic hydroxamic acids will be further investigated to find more potent compounds.
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Affiliation(s)
- Ilze Mutule
- Department of Organic Chemistry, Latvian Institute of Organic Synthesis , Riga , Latvia
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26
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Martin DP, Blachly PG, Marts AR, Woodruff TM, de Oliveira CAF, McCammon JA, Tierney DL, Cohen SM. 'Unconventional' coordination chemistry by metal chelating fragments in a metalloprotein active site. J Am Chem Soc 2014; 136:5400-6. [PMID: 24635441 PMCID: PMC4104174 DOI: 10.1021/ja500616m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
![]()
The
binding of three closely related chelators: 5-hydroxy-2-methyl-4H-pyran-4-thione (allothiomaltol, ATM), 3-hydroxy-2-methyl-4H-pyran-4-thione (thiomaltol, TM), and 3-hydroxy-4H-pyran-4-thione (thiopyromeconic acid, TPMA) to the active
site of human carbonic anhydrase II (hCAII) has been investigated.
Two of these ligands display a monodentate mode of coordination to
the active site Zn2+ ion in hCAII that is not recapitulated
in model complexes of the enzyme active site. This unprecedented binding
mode in the hCAII-thiomaltol complex has been characterized by both
X-ray crystallography and X-ray spectroscopy. In addition, the steric
restrictions of the active site force the ligands into a ‘flattened’
mode of coordination compared with inorganic model complexes. This
change in geometry has been shown by density functional computations
to significantly decrease the strength of the metal–ligand
binding. Collectively, these data demonstrate that the mode of binding
by small metal-binding groups can be significantly influenced by the
protein active site. Diminishing the strength of the metal–ligand
bond results in unconventional modes of metal coordination not found
in typical coordination compounds or even carefully engineered active
site models, and understanding these effects is critical to the rational
design of inhibitors that target clinically relevant metalloproteins.
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Affiliation(s)
- David P Martin
- Department of Chemistry and Biochemistry, §Pharmacology, and ∥Howard Hughes Medical Institute, University of California, San Diego , La Jolla, California 92093, United States
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27
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Neuman NI, Winkler E, Peña O, Passeggi MCG, Rizzi AC, Brondino CD. Magnetic properties of weakly exchange-coupled high spin Co(II) ions in pseudooctahedral coordination evaluated by single crystal X-band EPR spectroscopy and magnetic measurements. Inorg Chem 2014; 53:2535-44. [PMID: 24528370 DOI: 10.1021/ic402797t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We report single-crystal X-band EPR and magnetic measurements of the coordination polymer catena-(trans-(μ2-fumarato)tetraaquacobalt(II)), 1, and the Co(II)-doped Zn(II) analogue, 2, in different Zn:Co ratios. 1 presents two magnetically inequivalent high spin S = 3/2 Co(II) ions per unit cell, named A and B, in a distorted octahedral environment coordinated to four water oxygen atoms and trans coordinated to two carboxylic oxygen atoms from the fumarate anions, in which the Co(II) ions are linked by hydrogen bonds and fumarate molecules. Magnetic susceptibility and magnetization measurements of 1 indicate weak antiferromagnetic exchange interactions between the S = 3/2 spins of the Co(II) ions in the crystal lattice. Oriented single crystal EPR experiments of 1 and 2 were used to evaluate the molecular g-tensor and the different exchange coupling constants between the Co(II) ions, assuming an effective spin S′= 1/2. Unexpectedly, the eigenvectors of the molecular g-tensor were not lying along any preferential bond direction, indicating that, in high spin Co(II) ions in roughly octahedral geometry with approximately axial EPR signals, the presence of molecular pseudo axes in the metal site does not determine preferential directions for the molecular g-tensor. The EPR experiment and magnetic measurements, together with a theoretical analysis relating the coupling constants obtained from both techniques, allowed us to evaluate selectively the exchange coupling constant associated with hydrogen bonds that connect magnetically inequivalent Co(II) ions (|JAB(1/2)| = 0.055(2) cm(–1)) and the exchange coupling constant associated with a fumarate bridge connecting equivalent Co(II) ions (|JAA(1/2)| ≈ 0.25 (1) cm(–1)), in good agreement with the average J(3/2) value determined from magnetic measurements.
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Affiliation(s)
- Nicolás I Neuman
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral , S3000ZAA Santa Fe, Argentina
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28
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Das M, Chatterjee S, Harms K, Mondal TK, Chattopadhyay S. Formation of bis(μ-tetrazolato)dinickel(ii) complexes with N,N,O-donor Schiff bases via in situ 1,3-dipolar cyclo-additions: isolation of a novel bi-cyclic trinuclear nickel(ii)–sodium(i)–nickel(ii) complex. Dalton Trans 2014; 43:2936-47. [DOI: 10.1039/c3dt52796d] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Kraft BM, Brennessel WW. Chelation and Stereodynamic Equilibria in Neutral Hypercoordinate Organosilicon Complexes of 1-Hydroxy-2-pyridinone. Organometallics 2013. [DOI: 10.1021/om400907s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bradley M. Kraft
- Department of Chemistry, St. John Fisher College, Rochester, New York 14618, United States
| | - William W. Brennessel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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30
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Zhu RM, Hu L, Li YZ, Song Y, Zuo JL. Syntheses, crystal structures and properties of dinuclear hydrido-tris(3,5-diphenylpyrazol-1-yl)borate complexes with the S―S coupled and dimerized quinoxaline-2,3-dithiolate ligand. INORG CHEM COMMUN 2013. [DOI: 10.1016/j.inoche.2013.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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31
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Dubois C, Haudecoeur R, Orio M, Belle C, Bochot C, Boumendjel A, Hardré R, Jamet H, Réglier M. Versatile effects of aurone structure on mushroom tyrosinase activity. Chembiochem 2012; 13:559-65. [PMID: 22307818 DOI: 10.1002/cbic.201100716] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Indexed: 11/09/2022]
Abstract
Elucidation of the binding modes of Ty inhibitors is an important step for in-depth studies on how to regulate tyrosinase activity. In this paper we highlight the extraordinarily versatile effects of the aurone structure on mushroom Ty activity. Depending on the position of the OH group on the B-ring, aurones can behave either as substrates or as hyperbolic activators. The synthesis of a hybrid aurone through combination of an aurone moiety with HOPNO (2-hydroxypyridine N-oxide), a good metal chelate, led us to a new, efficient, mixed inhibitor for mushroom tyrosinase. Another important feature pointed out by our study is the presence of more than one site for aurone compounds on mushroom tyrosinase. Because study of the binding of the hybrid aurone was difficult to perform with the enzyme, we undertook binding studies with tyrosinase functional models in order to elucidate the binding mode (chelating vs. bridging) on a dicopper(II) center. Use of EPR combined with theoretical DFT calculations allowed us to propose a preferred chelating mode for the interaction of the hybrid aurone with a dicopper(II) center.
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Affiliation(s)
- Carole Dubois
- Institut des Sciences Moléculaires de Marseille, Équipe BiosCiences, UMR-CNRS 7313, Aix-Marseille Université Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France
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32
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Oseback SN, Shim SW, Kumar M, Greer SM, Gardner SR, Lemar KM, DeGregory PR, Papish ET, Tierney DL, Zeller M, Yap GPA. Crowded bis ligand complexes of TtzPh,Me with first row transition metals rearrange due to ligand field effects: structural and electronic characterization (TtzPh,Me = tris(3-phenyl-5-methyl-1,2,4-triazolyl)borate). Dalton Trans 2012; 41:2774-87. [DOI: 10.1039/c2dt12029a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Shannon N Oseback
- Departments of Chemistry, Drexel University, Philadelphia, PA 19104, USA
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33
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Mikhalyova EA, Kolotilov SV, Cador O, Zeller M, Trofimenko S, Ouahab L, Addison AW, Pavlishchuk VV, Hunter AD. The role of the bridging group in exchange coupling in dinuclear homo- and heterometallic Ni(ii) and Co(ii) complexes with oxalate, oxamidate and dithiooxamidate bridges. Dalton Trans 2012; 41:11319-29. [DOI: 10.1039/c2dt31121f] [Citation(s) in RCA: 8] [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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34
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Tabassum S, Khan RA, Arjmand F, Aziz M, Juvekar AS, Zingde SM. Carbohydrate-conjugate heterobimetallic complexes: synthesis, DNA binding studies, artificial nuclease activity and in vitro cytotoxicity. Carbohydr Res 2011; 346:2886-95. [PMID: 22055812 DOI: 10.1016/j.carres.2011.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 10/01/2011] [Accepted: 10/07/2011] [Indexed: 11/20/2022]
Abstract
New carbohydrate-conjugated heterobimetallic complexes [C(32)H(62)N(10)O(8)NiSn(2)Cl(4)]Cl(2)(1) and [C(32)H(62)N(10)O(8)CuSn(2)Cl(4)]Cl(2) (2) were synthesized and characterized by spectroscopic (IR, (1)H, (13)C, and (119)Sn NMR, EPR, UV-vis, ESI-MS) and analytical methods. The interaction studies of 2 with CT DNA were studied by using various biophysical techniques, which showed high binding affinity of 2 toward CT DNA. The extent of interaction was further confirmed by the interaction of 2 with the nucleotides viz.; 5'-AMP, 5'-CMP, 5'-GMP, and 5'-TMP, by absorption titration. (1)H, (31)P, (119)Sn NMR spectroscopy further validated the interaction mode of 2 with 5'-GMP. The electrophoresis pattern observed for 2 with supercoiled pBR322 DNA, exhibited significantly good nuclease activity following oxidative pathway. The preferential selectivity of 2 toward the major groove was observed on interaction of 2 with pBR322 DNA, in the presence of standard groove binders viz.; DAPI and methyl green. Additionally, in vitro antitumor activity of 2 was evaluated on a panel of human cancer cell lines, exhibiting remarkable cytotoxicity activity against Colo205 (colon) and MCF7 (breast) cell lines with GI(50) values <10 μg/mL.
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Affiliation(s)
- Sartaj Tabassum
- Department of Chemistry, Aligarh Muslim University, Aligarh 202 002, India.
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Mixed-ligand complexes of zinc(II), cobalt(II) and cadmium(II) with sulfur, nitrogen and oxygen ligands. Analysis of the solid state structure and solution behavior. Implications for metal ion substitution in alcohol dehydrogenase. Polyhedron 2011. [DOI: 10.1016/j.poly.2011.01.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Fielding AJ, Kovaleva EG, Farquhar ER, Lipscomb JD, Que L. A hyperactive cobalt-substituted extradiol-cleaving catechol dioxygenase. J Biol Inorg Chem 2011; 16:341-55. [PMID: 21153851 PMCID: PMC3192431 DOI: 10.1007/s00775-010-0732-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 10/27/2010] [Indexed: 11/27/2022]
Abstract
Homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum (HPCD) has an Fe(II) center in its active site that can be replaced with Mn(II) or Co(II). Whereas Mn-HPCD exhibits steady-state kinetic parameters comparable to those of Fe-HPCD, Co-HPCD behaves somewhat differently, exhibiting significantly higher [Formula: see text] and k (cat). The high activity of Co-HPCD is surprising, given that cobalt has the highest standard M(III/II) redox potential of the three metals. Comparison of the X-ray crystal structures of the resting and substrate-bound forms of Fe-HPCD, Mn-HPCD, and Co-HPCD shows that metal substitution has no effect on the local ligand environment, the conformational integrity of the active site, or the overall protein structure, suggesting that the protein structure does not differentially tune the potential of the metal center. Analysis of the steady-state kinetics of Co-HPCD suggests that the Co(II) center alters the relative rate constants for the interconversion of intermediates in the catalytic cycle but still allows the dioxygenase reaction to proceed efficiently. When compared with the kinetic data for Fe-HPCD and Mn-HPCD, these results show that dioxygenase catalysis can proceed at high rates over a wide range of metal redox potentials. This is consistent with the proposed mechanism in which the metal mediates electron transfer between the catechol substrate and O(2) to form the postulated [M(II)(semiquinone)superoxo] reactive species. These kinetic differences and the spectroscopic properties of Co-HPCD provide new tools with which to explore the unique O(2) activation mechanism associated with the extradiol dioxygenase family.
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Affiliation(s)
- Andrew J Fielding
- Department of Chemistry, Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street, Minneapolis, MN 55455, USA
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Harding DJ, Harding P, Dokmaisrijan S, Adams H. Redox-active nickel and cobalt tris(pyrazolyl)borate dithiocarbamate complexes: air-stable Co(ii) dithiocarbamates. Dalton Trans 2011; 40:1313-21. [DOI: 10.1039/c0dt01010c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Arjmand F, Muddassir M. A mechanistic approach for the DNA binding of chiral enantiomeric L- and D-tryptophan-derived metal complexes of 1,2-DACH: cleavage and antitumor activity. Chirality 2010; 23:250-9. [PMID: 20928895 DOI: 10.1002/chir.20907] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 06/16/2010] [Indexed: 01/23/2023]
Abstract
A new chiral series of potential antitumor metal-based complexes 1-3(a and b) of L- and D-tryptophan have been synthesized and thoroughly characterized. Both enantiomers of 1-3 bind DNA noncovalently via phosphate interaction with slight preference of metal center for covalent coordination to nucleobases. The K(b) values of L-enantiomer, however, possess higher propensity for DNA binding in comparison with the D-enantiomeric analogs. The relative trend in K(b) values is as follows: 2(a) > 2(b) > 3(a) > 1(a) > 3(b) > 1(b). These observations together with the findings of circular dichoric and fluorescence studies reveal maximal potential of L-enantiomeric form of copper complex to bind DNA, thereby exerting its therapeutic effect. The complex 2a exhibits a remarkable DNA cleavage activity with pBR322DNA in the presence of different activators such as H(2) O(2) , ascorbic acid, 3-mercaptopropionic acid, and glutathione, suggesting the involvement of active oxygen species for the DNA scission. In vitro anticancer activity of complexes 1-3(a) were screened against 14 different human carcinoma cell lines of different histological origin, and the results reveal that 2a shows significant antitumor activity in comparison with both 1a and 3a and is particularly selective for MIAPACA2 (pancreatic cancer cell line).
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Affiliation(s)
- Farukh Arjmand
- Department of Chemistry, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.
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Krzystek J, Swenson DC, Zvyagin SA, Smirnov D, Ozarowski A, Telser J. Cobalt(II) “Scorpionate” Complexes as Models for Cobalt-Substituted Zinc Enzymes: Electronic Structure Investigation by High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopy. J Am Chem Soc 2010; 132:5241-53. [PMID: 20329727 DOI: 10.1021/ja910766w] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Dale C. Swenson
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - S. A. Zvyagin
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Joshua Telser
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
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40
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Wrackmeyer B, Shahid K, Kempe R, Döring C, Milius W. Indazaboles-synthesis and molecular structure. Appl Organomet Chem 2010. [DOI: 10.1002/aoc.1627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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41
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Jakusch T, Dean A, Oncsik T, Bényei AC, Di Marco V, Kiss T. Vanadate complexes in serum: a speciation modeling study. Dalton Trans 2009:212-20. [PMID: 20023952 DOI: 10.1039/b914849c] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The speciations of two drug candidate ligands, 2-hydroxypyridine-N-oxide (Hhpno) and 2-mercaptopyridine-N-oxide (Hmpno), with vanadate (V(V)) were determined at 25.0 degrees C and 0.20 mol dm(-3) KCl by pH-metric and (51)V-NMR methods. At pH 7.4, the two predominant compounds with both ligands are the VO(2)L(2) and VO(2)L(OH). NH(4)[VO(2)(hpno)(2)] x 3 H(2)O was prepared in solid form, and its crystal structure was determined by X-ray diffraction. The stabilities of the complexes VO(2)L(2) of five drug candidate ligands were compared at pH 7.4. In view of the stability sequence hpno > maltol approximately hdp (Hhdp: 3-hydroxy-1,2-dimethyl-4-pyridinone) >> mpno > picolinic acid, the first two of these ligands were chosen for equilibrium studies with apotransferrin (apoTf) competition. The V(V)-apoTf stability constants (log K(1) = 6.03 +/- 0.10; log K(2) = 5.46 +/- 0.18) determined by (51)V-NMR spectroscopy were confirmed by ultrafiltration. Both methods proved that there seems to be no hydrogencarbonate-vanadate competition for the apoTf anion-binding positions. The other potential high molecular mass V(V) binder in the serum is human serum albumin (HSA). As no interaction was detected by (51)V-NMR spectroscopy or fluorimetry, the binding properties of HSA were quantified on the basis of literature data. As a final conclusion, speciation modeling calculations suggest that, under serum conditions, apoTf is probably the primary metal ion binder, even in the presence of the most stable V(V) carrier ligands hpno and maltol and HSA plays a negligible role in V(V) binding.
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Affiliation(s)
- Tamás Jakusch
- Department of Inorganic and Analytical Chemistry, University of Szeged, P.O. Box 440, Szeged, H-6701, Hungary
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Dołęga A, Pladzyk A, Baranowska K, Jezierska J. Biomimetic zinc(II) and cobalt(II) complexes with tri-tert-butoxysilanethiolate and imidazole ligands – Structural and spectroscopic studies. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2009.08.028] [Citation(s) in RCA: 27] [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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43
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Harding DJ, Harding P, Daengngern R, Yimklan S, Adams H. Synthesis and characterization of redox-active tris(pyrazolyl)borate cobalt complexes. Dalton Trans 2009:1314-20. [DOI: 10.1039/b815001j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Myers WK, Duesler EN, Tierney DL. Integrated paramagnetic resonance of high-spin Co(II) in axial symmetry: chemical separation of dipolar and contact electron-nuclear couplings. Inorg Chem 2008; 47:6701-10. [PMID: 18605690 DOI: 10.1021/ic800245k] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Integrated paramagnetic resonance, utilizing electron paramagnetic resonance (EPR), NMR, and electron-nuclear double resonance (ENDOR), of a series of cobalt bis-trispyrazolylborates, Co(Tp ( x )) 2, are reported. Systematic substitutions at the ring carbons and on the apical boron provide a unique opportunity to separate through-bond and through-space contributions to the NMR hyperfine shifts for the parent, unsubstituted Tp complex. A simple relationship between the chemical shift difference (delta H - delta Me) and the contact shift of the proton in that position is developed. This approach allows independent extraction of the isotropic hyperfine coupling, A iso, for each proton in the molecule. The Co..H contact coupling energies derived from the NMR, together with the known metrics of the compounds, were used to predict the ENDOR couplings at g perpendicular. Proton ENDOR data is presented that shows good agreement with the NMR-derived model. ENDOR signals from all other magnetic nuclei in the complex ( (14)N, coordinating and noncoordinating, (11)B and (13)C) are also reported.
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Affiliation(s)
- William K Myers
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, USA
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Roy S, Patra AK, Dhar S, Chakravarty AR. Photosensitizer in a Molecular Bowl and its Effect on the DNA-Binding and -Cleavage Activity of 3d-Metal Scorpionates. Inorg Chem 2008; 47:5625-33. [DOI: 10.1021/ic702508r] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Sovan Roy
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Ashis K. Patra
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Shanta Dhar
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Akhil R. Chakravarty
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
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46
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Fujisawa K, Kakizaki T, Miyashita Y, Okamoto KI. Structural and spectroscopic comparison of five-coordinate cobalt(II) and nickel(II) thiolato complexes with the related four-coordinate complexes. Inorganica Chim Acta 2008. [DOI: 10.1016/j.ica.2007.08.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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