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Churchman LR, Beckett JR, Tan L, Woods K, Doherty DZ, Ghith A, Bernhardt PV, Bell SG, West NP, De Voss JJ. Synthesis of steroidal inhibitors for Mycobacterium tuberculosis. J Steroid Biochem Mol Biol 2024; 239:106479. [PMID: 38346478 DOI: 10.1016/j.jsbmb.2024.106479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/23/2024] [Accepted: 02/07/2024] [Indexed: 02/19/2024]
Abstract
Oxidised derivatives of cholesterol have been shown to inhibit the growth of Mycobacterium tuberculosis (Mtb). The bacteriostatic activity of these compounds has been attributed to their inhibition of CYP125A1 and CYP142A1, two metabolically critical cytochromes P450 that initiate degradation of the sterol side chain. Here, we synthesise and characterise an extensive library of 28 cholesterol derivatives to develop a structure-activity relationship for this class of inhibitors. The candidate compounds were evaluated for MIC with virulent Mtb and in binding studies with CYP125A1 and CYP142A1 from Mtb.
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Affiliation(s)
- Luke R Churchman
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - James R Beckett
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Lendl Tan
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Kyra Woods
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Daniel Z Doherty
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Amna Ghith
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Stephen G Bell
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Nicholas P West
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia.
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2
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Geoghegan BL, Bilyj JK, Bernhardt PV, DeBeer S, Cutsail GE. X-ray absorption and emission spectroscopy of N 2S 2 Cu(II)/(III) complexes. Dalton Trans 2024. [PMID: 38624161 DOI: 10.1039/d4dt00085d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
This study investigates the influence of ligand charge on transition energies in a series of CuN2S2 complexes based on dithiocarbazate Schiff base ligands using Cu K-edge X-ray absorption spectroscopy (XAS) and Kβ valence-to-core (VtC) X-ray emission spectroscopy (XES). By comparing the formally Cu(II) complexes [CuII(HL1)] (HL12- = dimethyl pentane-2,4-diylidenebis[carbonodithiohydrazonate]) and [CuII(HL2)] (HL22- = dibenzyl pentane-2,4-diylidenebis[carbonodithiohydrazonate]) and the formally Cu(III) complex [CuIII(L2)], distinct changes in transition energies are observed, primarily attributed to the metal oxidation state. Density functional theory (DFT) calculations demonstrate how an increased negative charge on the deprotonated L23- ligand stabilizes the Cu(III) center through enhanced charge donation, modulating the core transition energies. Overall, significant shifts to higher energies are noted upon metal oxidation, emphasizing the importance of scrutinizing ligand structure in XAS/VtC XES analysis. The data further support the redox-innocent role of the Schiff base ligands and underscore the criticality of ligand protonation levels in future spectroscopic studies, particularly for catalytic intermediates. The combined XAS-VtC XES methodology validates the Cu(III) oxidation state assignment while offering insights into ligand protonation effects on core-level spectroscopic transitions.
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Affiliation(s)
- Blaise L Geoghegan
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
- Institute of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstrasse 5-7, 45117 Essen, Germany
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, W12 0BZ, London, UK
| | - Jessica K Bilyj
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
| | - George E Cutsail
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
- Institute of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstrasse 5-7, 45117 Essen, Germany
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3
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Su C, Dallaston MA, Watson RD, Fahrenhorst-Jones T, Cameron JP, Pierens GK, Bernhardt PV, Savage GP, Williams CM. The (±)-5-Aza[1.0]triblattane Skeleton via Azetine Cycloaddition. Org Lett 2024; 26:2827-2831. [PMID: 38253345 DOI: 10.1021/acs.orglett.3c03655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The first synthesis of the 5-aza[1.0]triblattane skeleton was achieved through a [4 + 2] cycloaddition approach using a suitably protected azetine and cyclopentadiene. A series of azetines were synthesized to explore both stability and suitable N-protection. The key step following cycloaddition utilized a noninitiated protonated aminyl radical cyclization to install the final 5-azatriblattane bond, but it was found to be considerably more unstable than the 6-aza isomer under acidic conditions.
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Affiliation(s)
- Chuyi Su
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland Australia
| | - Madeleine A Dallaston
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland Australia
| | - Renée D Watson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland Australia
| | - Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland Australia
| | - Jacob P Cameron
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland Australia
| | - Gregory K Pierens
- Centre for Advanced Imaging, University of Queensland, Brisbane, 4072 Queensland Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168 Victoria, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland Australia
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4
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Wijesinghe TP, Kaya B, Gonzálvez MA, Harmer JR, Gholam Azad M, Bernhardt PV, Dharmasivam M, Richardson DR. Correction to "Steric Blockade of Oxy-Myoglobin Oxidation by Thiosemicarbazones: Structure-Activity Relationships of the Novel PPP4pT Series''. J Med Chem 2024. [PMID: 38597697 DOI: 10.1021/acs.jmedchem.4c00714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
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5
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Naher M, Su C, Harmer JR, Williams CM, Bernhardt PV. Macrocyclic Copper(II) Complexes as Catalysts for Electrochemically Mediated Atom Transfer. Inorg Chem 2024; 63:6453-6464. [PMID: 38526552 DOI: 10.1021/acs.inorgchem.4c00311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Copper-catalyzed electrochemical atom transfer radical addition (eATRA) is a new method for the creation of new C-C bonds under mild conditions. In this work, we have explored the reactivity of an analogous series of N4 macrocyclic CuII complexes as eATRA precatalysts, which are primed by reduction to their monovalent oxidation state. These complexes were fully characterized structurally, spectroscopically, and electrochemically. A spectrum of radical activation reactivity was found across the series [CuI(Me4cyclen)(NCMe)]+ (Me4cyclen = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane), [CuI(Me4cyclam)(NCMe)]+ (Me4cyclam = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), and [CuI(Me2py2clen)(NCMe)]+ (Me2py2clen = 3,7-dimethyl-3,7-diaza-1,5(2,6)-dipyridinacyclo-octaphane). The rate of radical production by [Cu(Me2py2clen)(NCMe)]+ was modest, but rapid radical capture to form the organocopper complex [CuI(Me2py2clen)(CH2CN)] led to a dramatic acceleration in catalysis, greater than seen in any comparable Cu complex, but this led to rapid radical self-termination instead of radical addition.
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Affiliation(s)
- Masnun Naher
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Chuyi Su
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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6
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Wilson LA, Melville JN, Pedroso MM, Krco S, Hoelzle R, Zaugg J, Southam G, Virdis B, Evans P, Supper J, Harmer JR, Tyson G, Clark A, Schenk G, Bernhardt PV. Kinetic, electrochemical and spectral characterization of bacterial and archaeal rusticyanins; unexpected stability issues and consequences for applications in biotechnology. J Inorg Biochem 2024; 256:112539. [PMID: 38593609 DOI: 10.1016/j.jinorgbio.2024.112539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 04/11/2024]
Abstract
Motivated by the ambition to establish an enzyme-driven bioleaching pathway for copper extraction, properties of the Type-1 copper protein rusticyanin from Acidithiobacillus ferrooxidans (AfR) were compared with those from an ancestral form of this enzyme (N0) and an archaeal enzyme identified in Ferroplasma acidiphilum (FaR). While both N0 and FaR show redox potentials similar to that of AfR their electron transport rates were significantly slower. The lack of a correlation between the redox potentials and electron transfer rates indicates that AfR and its associated electron transfer chain evolved to specifically facilitate the efficient conversion of the energy of iron oxidation to ATP formation. In F. acidiphilum this pathway is not as efficient unless it is up-regulated by an as of yet unknown mechanism. In addition, while the electrochemical properties of AfR were consistent with previous data, previously unreported behavior was found leading to a form that is associated with a partially unfolded form of the protein. The cyclic voltammetry (CV) response of AfR immobilized onto an electrode showed limited stability, which may be connected to the presence of the partially unfolded state of this protein. Insights gained in this study may thus inform the engineering of optimized rusticyanin variants for bioleaching processes as well as enzyme-catalyzed solubilization of copper-containing ores such as chalcopyrite.
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Affiliation(s)
- Liam A Wilson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jamie N Melville
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Marcelo M Pedroso
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Stefan Krco
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert Hoelzle
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Julian Zaugg
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gordon Southam
- School of the Environment, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul Evans
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jenna Supper
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jeffrey R Harmer
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gene Tyson
- Centre for Microbiome Research, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Alice Clark
- Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia; Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
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7
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Dharmasivam M, Kaya B, Wijesinghe TP, Richardson V, Harmer JR, Gonzalvez MA, Lewis W, Azad MG, Bernhardt PV, Richardson DR. Differential transmetallation of complexes of the anti-cancer thiosemicarbazone, Dp4e4mT: effects on anti-proliferative efficacy, redox activity, oxy-myoglobin and oxy-hemoglobin oxidation. Chem Sci 2024; 15:974-990. [PMID: 38239703 PMCID: PMC10793205 DOI: 10.1039/d3sc05723b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024] Open
Abstract
The di-2-pyridylthiosemicarbazone (DpT) analogs demonstrate potent and selective anti-proliferative activity against human tumors. The current investigation reports the synthesis and chemical and biological characterization of the Fe(iii), Co(iii), Ni(ii), Cu(ii), Zn(ii), Ga(iii), and Pd(ii) complexes of the promising second generation DpT analog, di-2-pyridylketone-4-ethyl-4-methyl-3-thiosemicarbazone (Dp4e4mT). These studies demonstrate that the Dp4e4mT Co(iii), Ni(ii), and Pd(ii) complexes display distinct biological activity versus those with Cu(ii), Zn(ii), and Ga(iii) regarding anti-proliferative efficacy against cancer cells and a detrimental off-target effect involving oxidation of oxy-myoglobin (oxy-Mb) and oxy-hemoglobin (oxy-Hb). With regards to anti-proliferative activity, the Zn(ii) and Ga(iii) Dp4e4mT complexes demonstrate facile transmetallation with Cu(ii), resulting in efficacy against tumor cells that is strikingly similar to the Dp4e4mT Cu(ii) complex (IC50: 0.003-0.006 μM and 72 h). Relative to the Zn(ii) and Ga(iii) Dp4e4mT complexes, the Dp4e4mT Ni(ii) complex demonstrates kinetically slow transmetallation with Cu(ii) and intermediate anti-proliferative effects (IC50: 0.018-0.076 μM after 72 h). In contrast, the Co(iii) and Pd(ii) complexes demonstrate poor anti-proliferative activity (IC50: 0.262-1.570 μM after 72 h), probably due to a lack of transmetallation with Cu(ii). The poor efficacy of the Dp4e4mT Co(iii), Ni(ii), and Pd(ii) complexes to transmetallate with Fe(iii) markedly suppresses the oxidation of oxy-Mb and oxy-Hb. In contrast, the 2 : 1 Dp4e4mT: Cu(ii), Zn(ii), and Ga(iii) complexes demonstrate facile reactions with Fe(iii), leading to the redox active Dp4e4mT Fe(iii) complex and oxy-Mb and oxy-Hb oxidation. This study demonstrates the key role of differential transmetallation of Dp4e4mT complexes that has therapeutic ramifications for their use as anti-cancer agents.
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Affiliation(s)
- Mahendiran Dharmasivam
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney Sydney New South Wales 2006 Australia
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University Nathan Brisbane Queensland 4111 Australia
| | - Busra Kaya
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University Nathan Brisbane Queensland 4111 Australia
| | - Tharushi P Wijesinghe
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University Nathan Brisbane Queensland 4111 Australia
| | - Vera Richardson
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University Nathan Brisbane Queensland 4111 Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland Brisbane Queensland 4072 Australia
| | - Miguel A Gonzalvez
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane Queensland 4072 Australia
| | - William Lewis
- Department of Chemistry, University of Sydney New South Wales 2006 Australia
| | - Mahan Gholam Azad
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University Nathan Brisbane Queensland 4111 Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane Queensland 4072 Australia
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney Sydney New South Wales 2006 Australia
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University Nathan Brisbane Queensland 4111 Australia
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine Nagoya 466-8550 Japan
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8
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Fahrenhorst-Jones T, Marshall DL, Burns JM, Pierens GK, Van Meurs DP, Kong D, Bernhardt PV, Blanksby SJ, Savage GP, Eaton PE, Williams CM. 9-Azahomocubane. Chemistry 2024; 30:e202303133. [PMID: 37823679 DOI: 10.1002/chem.202303133] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/13/2023]
Abstract
Homocubane, a highly strained cage hydrocarbon, contains two very different positions for the introduction of a nitrogen atom into the skeleton, e. g., a position 1 exchange results in a tertiary amine whereas position 9 yields a secondary amine. Herein reported is the synthesis of 9-azahomocubane along with associated structural characterization, physical property analysis and chemical reactivity. Not only is 9-azahomocubane readily synthesized, and found to be stable as predicted, the basicity of the secondary amine was observed to be significantly lower than the structurally related azabicyclo[2.2.1]heptane, although similar to 1-azahomocubane.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - David L Marshall
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Gregory K Pierens
- Centre for Advanced imaging, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Derek P Van Meurs
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Dehui Kong
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria, Australia
| | - Philip E Eaton
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
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9
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Harmer JR, Hakopian S, Niks D, Hille R, Bernhardt PV. Redox Characterization of the Complex Molybdenum Enzyme Formate Dehydrogenase from Cupriavidus necator. J Am Chem Soc 2023; 145:25850-25863. [PMID: 37967365 DOI: 10.1021/jacs.3c10199] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
The oxygen-tolerant and molybdenum-dependent formate dehydrogenase FdsDABG from Cupriavidus necator is capable of catalyzing both formate oxidation to CO2 and the reverse reaction (CO2 reduction to formate) at neutral pH, which are both reactions of great importance to energy production and carbon capture. FdsDABG is replete with redox cofactors comprising seven Fe/S clusters, flavin mononucleotide, and a molybdenum ion coordinated by two pyranopterin dithiolene ligands. The redox potentials of these centers are described herein and assigned to specific cofactors using combinations of potential-dependent continuous wave and pulse EPR spectroscopy and UV/visible spectroelectrochemistry on both the FdsDABG holoenzyme and the FdsBG subcomplex. These data represent the first redox characterization of a complex metal dependent formate dehydrogenase and provide an understanding of the highly efficient catalytic formate oxidation and CO2 reduction activity that are associated with the enzyme.
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Affiliation(s)
- Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Sheron Hakopian
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Dimitri Niks
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Russ Hille
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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10
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Wijesinghe TP, Kaya B, Gonzálvez MA, Harmer JR, Gholam Azad M, Bernhardt PV, Dharmasivam M, Richardson DR. Steric Blockade of Oxy-Myoglobin Oxidation by Thiosemicarbazones: Structure-Activity Relationships of the Novel PPP4pT Series. J Med Chem 2023; 66:15453-15476. [PMID: 37922410 DOI: 10.1021/acs.jmedchem.3c01612] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2023]
Abstract
The di-2-pyridylketone thiosemicarbazones demonstrated marked anticancer efficacy, prompting progression of DpC to clinical trials. However, DpC induced deleterious oxy-myoglobin oxidation, stifling development. To address this, novel substituted phenyl thiosemicarbazone (PPP4pT) analogues and their Fe(III), Cu(II), and Zn(II) complexes were prepared. The PPP4pT analogues demonstrated potent antiproliferative activity (IC50: 0.009-0.066 μM), with the 1:1 Cu:L complexes showing the greatest efficacy. Substitutions leading to decreased redox potential of the PPP4pT:Cu(II) complexes were associated with higher antiproliferative activity, while increasing potential correlated with increased redox activity. Surprisingly, there was no correlation between redox activity and antiproliferative efficacy. The PPP4pT:Fe(III) complexes attenuated oxy-myoglobin oxidation significantly more than the clinically trialed thiosemicarbazones, Triapine, COTI-2, and DpC, or earlier thiosemicarbazone series. Incorporation of phenyl- and styryl-substituents led to steric blockade, preventing approach of the PPP4pT:Fe(III) complexes to the heme plane and its oxidation. The 1:1 Cu(II):PPP4pT complexes were inert to transmetalation and did not induce oxy-myoglobin oxidation.
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Affiliation(s)
- Tharushi P Wijesinghe
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane 4111, Australia
| | - Busra Kaya
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane 4111, Australia
| | - Miguel A Gonzálvez
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Mahan Gholam Azad
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane 4111, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Mahendiran Dharmasivam
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane 4111, Australia
| | - Des R Richardson
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane 4111, Australia
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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11
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Kalimuthu P, Hakopian S, Niks D, Hille R, Bernhardt PV. The Reversible Electrochemical Interconversion of Formate and CO 2 by Formate Dehydrogenase from Cupriavidus necator. J Phys Chem B 2023; 127:8382-8392. [PMID: 37728992 DOI: 10.1021/acs.jpcb.3c04652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The bacterial molybdenum (Mo)-containing formate dehydrogenase (FdsDABG) from Cupriavidus necator is a soluble NAD+-dependent enzyme belonging to the DMSO reductase family. The holoenzyme is complex and possesses nine redox-active cofactors including a bis(molybdopterin guanine dinucleotide) (bis-MGD) active site, seven iron-sulfur clusters, and 1 equiv of flavin mononucleotide (FMN). FdsDABG catalyzes the two-electron oxidation of HCOO- (formate) to CO2 and reversibly reduces CO2 to HCOO- under physiological conditions close to its thermodynamic redox potential. Here we develop an electrocatalytically active formate oxidation/CO2 reduction system by immobilizing FdsDABG on a glassy carbon electrode in the presence of coadsorbents such as chitosan and glutaraldehyde. The reversible enzymatic interconversion between HCOO- and CO2 by FdsDABG has been realized with cyclic voltammetry using a range of artificial electron transfer mediators, with methylene blue (MB) and phenazine methosulfate (PMS) being particularly effective as electron acceptors for FdsDABG in formate oxidation. Methyl viologen (MV) acts as both an electron acceptor (MV2+) in formate oxidation and an electron donor (MV+•) for CO2 reduction. The catalytic voltammetry was reproduced by electrochemical simulation across a range of sweep rates and concentrations of formate and mediators to provide new insights into the kinetics of the FdsDABG catalytic mechanism.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Sheron Hakopian
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Dimitri Niks
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Russ Hille
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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12
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Naher M, Su C, Harmer JR, Williams CM, Bernhardt PV. Electrocatalytic Atom Transfer Radical Addition with Turbocharged Organocopper(II) Complexes. Inorg Chem 2023; 62:15575-15583. [PMID: 37712595 DOI: 10.1021/acs.inorgchem.3c02106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
The utility and scope of Cu-catalyzed halogen atom transfer chemistry have been exploited in the fields of atom transfer radical polymerization and atom transfer radical addition, where the metal plays a key role in radical formation and minimizing unwanted side reactions. We have shown that electrochemistry can be employed to modulate the reactivity of the Cu catalyst between its active (CuI) and dormant (CuII) states in a variety of ligand systems. In this work, a macrocyclic pyridinophane ligand (L1) was utilized, which can break the C-Br bond of BrCH2CN to release •CH2CN radicals when in complex with CuI. Moreover, the [CuI(L1)]+ complex can capture the •CH2CN radical to form a new species [CuII(L1)(CH2CN)]+ in situ that, on reduction, exhibits halogen atom transfer reactivity 3 orders of magnitude greater than its parent complex [CuI(L1)]+. This unprecedented rate acceleration has been identified by electrochemistry, successfully reproduced by simulation, and exploited in a Cu-catalyzed bulk electrosynthesis where [CuII(L1)(CH2CN)]+ participates as a radical donor in the atom transfer radical addition of BrCH2CN to a selection of styrenes. The formation of these turbocharged catalysts in situ during electrosynthesis offers a new approach to the Cu-catalyzed organic reaction methodology.
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Affiliation(s)
- Masnun Naher
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Chuyi Su
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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13
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Fahrenhorst-Jones T, Kong D, Burns JM, Pierens GK, Bernhardt PV, Savage GP, Williams CM. seco-1-Azacubane-2-carboxylic acid-Amide Bond Comparison to Proline. J Org Chem 2023; 88:12867-12871. [PMID: 37647582 DOI: 10.1021/acs.joc.3c01264] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
seco-1-Azacubane-2-carboxylic acid, an unusual and sterically constrained amino acid, was found to undergo amide bond formation at both the N- and C-termini using proline based bioactive molecule templates as a concept platform.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Dehui Kong
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Gregory K Pierens
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, Victoria 3168, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
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14
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Gonzálvez MA, Williams CM, Martínez M, Bernhardt PV. Kinetico-Mechanistic Studies on a Reactive Organocopper(II) Complex: Cu-C Bond Homolysis versus Heterolysis. Inorg Chem 2023; 62:4662-4671. [PMID: 36877141 DOI: 10.1021/acs.inorgchem.3c00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Organocopper(II) reagents are an unexplored frontier of copper catalysis. Despite being proposed as reactive intermediates, an understanding of the stability and reactivity of the CuII-C bond has remained elusive. Two main pathways can be considered for the cleavage mode of a CuII-C bond: homolysis and heterolysis. We recently showed how organocopper(II) reagents can react with alkenes via radical addition, a homolytic pathway. In this work, the decomposition of the complex [CuIILR]+ [L = tris(2- dimethylaminoethyl)amine, Me6tren, R = NCCH2-] in the absence and presence of an initiator (RX, X = Cl, Br) was evaluated. When no initiator was present, first-order CuII-C bond homolysis occurred producing [CuIL]+ and succinonitrile, via radical termination. When an excess of the initiator was present, a subsequent formation of [CuIILX]+ via a second-order reaction was found, which results from the reaction of [CuIL]+ with RX following homolysis. However, when Brønsted acids (R'-OH: R' = H, Me, Ph, PhCO) were present, heterolytic cleavage of the CuII-C bond produced [CuIIL(OR')]+ and MeCN. Kinetic studies were undertaken to obtain the thermal (ΔH⧧, ΔS⧧) and pressure (ΔV⧧) activation parameters and deuterium kinetic isotopic effects, which provided an understanding of the strength of the CuII-C bond and the nature of the transition state for the reactions involved. These results reveal possible reaction pathways for organocopper(II) complexes relevant to their applications as catalysts in C-C bond forming reactions.
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Affiliation(s)
- Miguel A Gonzálvez
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Manuel Martínez
- Departament de Química Inorgànica i Orgànica, Secció de Química Inorgànica, Universitat de Barcelona, Martí i Franquès 1-11, Barcelona 08028, Spain.,Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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15
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Fahrenhorst-Jones T, Marshall DL, Burns JM, Pierens GK, Hormann RE, Fisher AM, Bernhardt PV, Blanksby SJ, Savage GP, Eaton PE, Williams CM. 1-Azahomocubane. Chem Sci 2023; 14:2821-2825. [PMID: 36937576 PMCID: PMC10016339 DOI: 10.1039/d3sc00001j] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Highly strained cage hydrocarbons have long stood as fundamental molecules to explore the limits of chemical stability and reactivity, probe physical properties, and more recently as bioactive molecules and in materials discovery. Interestingly, the nitrogenous congeners have attracted much less attention. Previously absent from the literature, azahomocubanes, offer an opportunity to investigate the effects of a nitrogen atom when incorporated into a highly constrained polycyclic environment. Herein disclosed is the synthesis of 1-azahomocubane, accompanied by comprehensive structural characterization, physical property analysis and chemical reactivity. These data support the conclusion that nitrogen is remarkably well tolerated in a highly strained environment.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
| | - David L Marshall
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology Brisbane 4000 Queensland Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
| | - Gregory K Pierens
- Centre for Advanced Imaging, University of Queensland Brisbane 4072 Queensland Australia
| | - Robert E Hormann
- Department of Chemistry, University of Chicago Chicago Illinois 60637 USA
| | - Allison M Fisher
- Department of Chemistry, University of Chicago Chicago Illinois 60637 USA
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology Brisbane 4000 Queensland Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory Melbourne 3168 Victoria Australia
| | - Philip E Eaton
- Department of Chemistry, University of Chicago Chicago Illinois 60637 USA
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland Brisbane 4072 Queensland Australia
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16
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Doherty GG, Ler GJM, Wimmer N, Bernhardt PV, Ashmus RA, Vocadlo DJ, Armstrong Z, Davies GJ, Maccarana M, Li JP, Kayal Y, Ferro V. Synthesis of Uronic Acid 1-Azasugars as Putative Inhibitors of α-Iduronidase, β-Glucuronidase and Heparanase. Chembiochem 2023; 24:e202200619. [PMID: 36453606 DOI: 10.1002/cbic.202200619] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/01/2022] [Accepted: 12/01/2022] [Indexed: 12/03/2022]
Abstract
1-Azasugar analogues of l-iduronic acid (l-IdoA) and d-glucuronic acid (d-GlcA) and their corresponding enantiomers have been synthesized as potential pharmacological chaperones for mucopolysaccharidosis I (MPS I), a lysosomal storage disease caused by mutations in the gene encoding α-iduronidase (IDUA). The compounds were efficiently synthesized in nine or ten steps from d- or l-arabinose, and the structures were confirmed by X-ray crystallographic analysis of key intermediates. All compounds were inactive against IDUA, although l-IdoA-configured 8 moderately inhibited β-glucuronidase (β-GLU). The d-GlcA-configured 9 was a potent inhibitor of β-GLU and a moderate inhibitor of the endo-β-glucuronidase heparanase. Co-crystallization of 9 with heparanase revealed that the endocyclic nitrogen of 9 forms close interactions with both the catalytic acid and catalytic nucleophile.
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Affiliation(s)
- Gareth G Doherty
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Geraldine Jia Ming Ler
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Norbert Wimmer
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Roger A Ashmus
- Department of Chemistry and, Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - David J Vocadlo
- Department of Chemistry and, Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Zachary Armstrong
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
- Current address: Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Gideon J Davies
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
- Current address: Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Marco Maccarana
- Department of Medical Biochemistry and Microbiology, The Biomedical Center, University of Uppsala, 75123, Uppsala, Sweden
| | - Jin-Ping Li
- Department of Medical Biochemistry and Microbiology, The Biomedical Center, University of Uppsala, 75123, Uppsala, Sweden
| | - Yasmin Kayal
- Technion Integrated Cancer Center (TICC), Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Vito Ferro
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
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17
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Bayaraa T, Lonhienne T, Sutiono S, Melse O, Brück TB, Marcellin E, Bernhardt PV, Boden M, Harmer JR, Sieber V, Guddat LW, Schenk G. Structural and Functional Insight into the Mechanism of the Fe-S Cluster-Dependent Dehydratase from Paralcaligenes ureilyticus. Chemistry 2023; 29:e202203140. [PMID: 36385513 PMCID: PMC10107998 DOI: 10.1002/chem.202203140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/18/2022]
Abstract
Enzyme-catalyzed reaction cascades play an increasingly important role for the sustainable manufacture of diverse chemicals from renewable feedstocks. For instance, dehydratases from the ilvD/EDD superfamily have been embedded into a cascade to convert glucose via pyruvate to isobutanol, a platform chemical for the production of aviation fuels and other valuable materials. These dehydratases depend on the presence of both a Fe-S cluster and a divalent metal ion for their function. However, they also represent the rate-limiting step in the cascade. Here, catalytic parameters and the crystal structure of the dehydratase from Paralcaligenes ureilyticus (PuDHT, both in presence of Mg2+ and Mn2+ ) were investigated. Rate measurements demonstrate that the presence of stoichiometric concentrations Mn2+ promotes higher activity than Mg2+ , but at high concentrations the former inhibits the activity of PuDHT. Molecular dynamics simulations identify the position of a second binding site for the divalent metal ion. Only binding of Mn2+ (not Mg2+ ) to this site affects the ligand environment of the catalytically essential divalent metal binding site, thus providing insight into an inhibitory mechanism of Mn2+ at higher concentrations. Furthermore, in silico docking identified residues that play a role in determining substrate binding and selectivity. The combined data inform engineering approaches to design an optimal dehydratase for the cascade.
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Affiliation(s)
- Tenuun Bayaraa
- School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Australia
| | - Thierry Lonhienne
- School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Australia
| | - Samuel Sutiono
- Chair of Chemistry of Biogenic resources, Campus Straubing for Biotechnology and Sustainability, Technical University of Munich, 94315, Straubing, Germany
| | - Okke Melse
- Chair of Chemistry of Biogenic resources, Campus Straubing for Biotechnology and Sustainability, Technical University of Munich, 94315, Straubing, Germany
| | - Thomas B Brück
- Werner Siemens Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, Brisbane, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Australia
| | - Mikael Boden
- School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, The University of Queensland, 4072, Brisbane, Australia
| | - Volker Sieber
- School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Australia.,Chair of Chemistry of Biogenic resources, Campus Straubing for Biotechnology and Sustainability, Technical University of Munich, 94315, Straubing, Germany
| | - Luke W Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Australia
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Australia.,Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, Brisbane, Australia.,Sustainable Minerals Institute, The University of Queensland, 4072, Brisbane, Australia
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18
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Connolly BJP, Lian JYJ, Bernhardt PV, Riley MJ. Ab Initio Investigation of the Na 3[Ln(ODA) 3]·2NaClO 4·6H 2O (Ln = Ce-Yb; ODA = Oxydiacetate) Series. Inorg Chem 2023; 62:1328-1340. [PMID: 36651855 DOI: 10.1021/acs.inorgchem.2c01764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this work, the Na3[Ln(ODA)3]·2NaClO4·6H2O (Ln = Ce-Yb; ODA = oxydiacetate) series was analyzed with the ab initio ligand field theory (AILFT) module of the ORCA computational suite. The results were discussed within the framework of the angular overlap model (AOM) and compared to literature data. We find that the structural changes observed across the series exemplifies the effects of the lanthanide contraction also manifesting in the value of the AOM parameters. It is also shown that the complete active space self-consistent field (CASSCF) methodology is sufficient to describe the ligand field interactions in mononuclear lanthanide complexes, and the effects of dynamic correlation, through n-electron valence state perturbation theory (NEVPT2), are discussed. The calculated ligand field parameters of the present work are compared to the experimentally derived values from the literature.
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Affiliation(s)
- Blake J P Connolly
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD4072, Australia
| | - James Y J Lian
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD4072, Australia
| | - Mark J Riley
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD4072, Australia
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19
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Dharmasivam M, Kaya B, Wijesinghe T, Gholam Azad M, Gonzálvez MA, Hussaini M, Chekmarev J, Bernhardt PV, Richardson DR. Designing Tailored Thiosemicarbazones with Bespoke Properties: The Styrene Moiety Imparts Potent Activity, Inhibits Heme Center Oxidation, and Results in a Novel "Stealth Zinc(II) Complex". J Med Chem 2023; 66:1426-1453. [PMID: 36649565 DOI: 10.1021/acs.jmedchem.2c01600] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A novel, potent, and selective antitumor agent, namely (E)-3-phenyl-1-(2-pyridinyl)-2-propen-1-one 4,4-dimethyl-3-thiosemicarbazone (PPP44mT), and its analogues were synthesized and characterized and displayed strikingly distinctive properties. This activity was mediated by the inclusion of a styrene moiety, which through steric and electrochemical mechanisms prevented deleterious oxy-myoglobin or oxy-hemoglobin oxidation relative to other potent thiosemicarbazones, i.e., di-2-pyridylketone-4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) or di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT). Structure-activity relationship analysis demonstrated specific tuning of PPP44mT electrochemistry further inhibited oxy-myoglobin or oxy-hemoglobin oxidation. Both PPP44mT and its Cu(II) complexes showed conspicuous almost immediate cytotoxicity against SK-N-MC tumor cells (within 3 h). In contrast, [Zn(PPP44mT)2] demonstrated a pronounced delay in activity, taking 48 h before marked antiproliferative efficacy was apparent. As such, [Zn(PPP44mT)2] was designated as a "stealth Zn(II) complex" that overcomes the near immediate cytotoxicity of PPP44mT or its copper complexes. Upon examination of the suppression of oncogenic signaling, [Zn(PPP44mT)2] was superior at inhibiting cyclin D1 expression compared to DpC or Dp44mT.
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Affiliation(s)
- Mahendiran Dharmasivam
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan4111, Australia
| | - Busra Kaya
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan4111, Australia.,Department of Chemistry, Istanbul University-Cerrahpasa, Avcilar, 34320Istanbul, Turkey
| | - Tharushi Wijesinghe
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan4111, Australia
| | - Mahan Gholam Azad
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan4111, Australia
| | - Miguel A Gonzálvez
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane4072, Australia
| | - Mohammad Hussaini
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan4111, Australia
| | - Jason Chekmarev
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan4111, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane4072, Australia
| | - Des R Richardson
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan4111, Australia.,Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
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20
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Kalimuthu P, Hege D, Winiarska A, Gemmecker Y, Szaleniec M, Heider J, Bernhardt PV. Electrocatalytic Aldehyde Oxidation by a Tungsten Dependent Aldehyde Oxidoreductase from Aromatoleum Aromaticum. Chemistry 2023; 29:e202203072. [PMID: 36648073 DOI: 10.1002/chem.202203072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 01/08/2023] [Accepted: 01/16/2023] [Indexed: 01/18/2023]
Abstract
In contrast to their molybdenum dependent relatives, tungsten enzymes operate at significantly lower redox potentials, and in some cases they can carry out reversible redox transformations of their substrates and products. Still, the electrochemical properties of W enzymes have received much less attention than their Mo relatives. Herein we analyse the tungsten enzyme aldehyde oxidoreductase (AOR) from the mesophilic bacterium Aromatoleum aromaticum which has been immobilised on a glassy carbon working electrode. This generates a functional system that electrochemically oxidises a wide variety of aromatic and aliphatic aldehydes in the presence of the electron transfer mediators benzyl viologen, methylene blue or dichlorophenol indophenol. Simulation of the cyclic voltammetry has enabled a thorough kinetic analysis of the system, which reveals that methylene blue acts as a two-electron acceptor. In contrast, the other two mediators act as single electron oxidants. The different electrochemical driving forces imparted by these mediators also lead to significantly different outer sphere electron transfer rates with AOR. This work shows that electrocatalytic aldehyde oxidation can be achieved at a low applied electrochemical potential leading to an extremely energy efficient catalytic process.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Dominik Hege
- Laboratory for Microbial Biochemistry, and, Center for Synthetic Microbiology, Philipps University Marburg, 35043, Marburg, Germany
| | - Agnieszka Winiarska
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek Kraków, 8, 30 239, Cracow, Poland
| | - Yvonne Gemmecker
- Laboratory for Microbial Biochemistry, and, Center for Synthetic Microbiology, Philipps University Marburg, 35043, Marburg, Germany
| | - Maciej Szaleniec
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek Kraków, 8, 30 239, Cracow, Poland
| | - Johann Heider
- Laboratory for Microbial Biochemistry, and, Center for Synthetic Microbiology, Philipps University Marburg, 35043, Marburg, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
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21
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Bettencourt CJ, Krainz T, Chow S, Parr BT, Tracy WF, Bernhardt PV, Davies HML, Williams CM. Unearthing the Subtleties of Rhodium(II)-Catalyzed Carbenoid Cycloadditions to Furans with an N-Sulfonyl-1,2,3-triazole Probe. Org Lett 2022; 24:9290-9295. [PMID: 36512372 DOI: 10.1021/acs.orglett.2c03869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The rhodium(II)-catalyzed reaction of a model alkenyl donor/acceptor N-sulfonyltriazole with a wide selection of furans is reported. This investigation unearthed a range of structurally diverse carbocyclic and ring-opened products, in good to excellent yields. The products obtained are proposed to arise selectively via cyclopropanation or zwitterionic rearrangement pathways, which are highly dependent on both the structural and electronic features of the furan substrate.
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Affiliation(s)
- Christian J Bettencourt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Tanja Krainz
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sharon Chow
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Brendan T Parr
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - William F Tracy
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Huw M L Davies
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
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22
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Kalimuthu P, Harmer JR, Baldauf M, Hassan AH, Kruse T, Bernhardt PV. Catalytic electrochemistry of the bacterial Molybdoenzyme YcbX. Biochim Biophys Acta Bioenerg 2022; 1863:148579. [PMID: 35640667 DOI: 10.1016/j.bbabio.2022.148579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 05/02/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Molybdenum-dependent enzymes that can reduce N-hydroxylated substrates (e.g. N-hydroxyl-purines, amidoximes) are found in bacteria, plants and vertebrates. They are involved in the conversion of a wide range of N-hydroxylated organic compounds into their corresponding amines, and utilize various redox proteins (cytochrome b5, cyt b5 reductase, flavin reductase) to deliver reducing equivalents to the catalytic centre. Here we present catalytic electrochemistry of the bacterial enzyme YcbX from Escherichia coli utilizing the synthetic electron transfer mediator methyl viologen (MV2+). The electrochemically reduced form (MV+.) acts as an effective electron donor for YcbX. To immobilize YcbX on a glassy carbon electrode, a facile protein crosslinking approach was used with the crosslinker glutaraldehyde (GTA). The YcbX-modified electrode showed a catalytic response for the reduction of a broad range of N-hydroxylated substrates. The catalytic activity of YcbX was examined at different pH values exhibiting an optimum at pH 7.5 and a bell-shaped pH profile with deactivation through deprotonation (pKa1 9.1) or protonation (pKa2 6.1). Electrochemical simulation was employed to obtain new biochemical data for YcbX, in its reaction with methyl viologen and the organic substrates 6-N-hydroxylaminopurine (6-HAP) and benzamidoxime (BA).
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Milena Baldauf
- Department of Plant Biology, Technische Universitaet, Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Ahmed H Hassan
- Department of Plant Biology, Technische Universitaet, Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Tobias Kruse
- Department of Plant Biology, Technische Universitaet, Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia.
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23
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Ang CW, Lee BM, Jackson CJ, Wang Y, Franzblau SG, Francisco AF, Kelly JM, Bernhardt PV, Tan L, West NP, Sykes ML, Hinton AO, Bolisetti R, Avery VM, Cooper MA, Blaskovich MA. Nitroimidazopyrazinones with Oral Activity against Tuberculosis and Chagas Disease in Mouse Models of Infection. J Med Chem 2022; 65:13125-13142. [DOI: 10.1021/acs.jmedchem.2c00972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chee Wei Ang
- Center for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
- School of Science, Monash University Malaysia, Subang Jaya, 47500 Selangor, Malaysia
| | - Brendon M. Lee
- Research School of Chemistry, Australian National University, Sullivans Creek Road, Acton ACT 2601, Australia
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medical College, New York, New York 10021, United States
| | - Colin J. Jackson
- Research School of Chemistry, Australian National University, Sullivans Creek Road, Acton ACT 2601, Australia
| | - Yuehong Wang
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Scott G. Franzblau
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Amanda F. Francisco
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - John M. Kelly
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Lendl Tan
- School of Chemistry and Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Nicholas P. West
- School of Chemistry and Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Melissa L. Sykes
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, Queensland 4111, Australia
| | - Alexandra O. Hinton
- Center for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Raghu Bolisetti
- Center for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Vicky M. Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, Queensland 4111, Australia
- School of Environment and Science, Griffith University, Nathan, Queensland 4111, Australia
| | - Matthew A. Cooper
- Center for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Mark A.T. Blaskovich
- Center for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
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24
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Bayaraa T, Gaete J, Sutiono S, Kurz J, Lonhienne T, Harmer JR, Bernhardt PV, Sieber V, Guddat L, Schenk G. Dihydroxy‐Acid Dehydratases From Pathogenic Bacteria: Emerging Drug Targets to Combat Antibiotic Resistance. Chemistry 2022; 28:e202200927. [PMID: 35535733 PMCID: PMC9543379 DOI: 10.1002/chem.202200927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Indexed: 11/30/2022]
Abstract
There is an urgent global need for the development of novel therapeutics to combat the rise of various antibiotic‐resistant superbugs. Enzymes of the branched‐chain amino acid (BCAA) biosynthesis pathway are an attractive target for novel anti‐microbial drug development. Dihydroxy‐acid dehydratase (DHAD) is the third enzyme in the BCAA biosynthesis pathway. It relies on an Fe−S cluster for catalytic activity and has recently also gained attention as a catalyst in cell‐free enzyme cascades. Two types of Fe−S clusters have been identified in DHADs, i.e. [2Fe−2S] and [4Fe−4S], with the latter being more prone to degradation in the presence of oxygen. Here, we characterise two DHADs from bacterial human pathogens, Staphylococcus aureus and Campylobacter jejuni (SaDHAD and CjDHAD). Purified SaDHAD and CjDHAD are virtually inactive, but activity could be reversibly reconstituted in vitro (up to ∼19,000‐fold increase with kcat as high as ∼6.7 s−1). Inductively‐coupled plasma‐optical emission spectroscopy (ICP‐OES) measurements are consistent with the presence of [4Fe−4S] clusters in both enzymes. N‐isopropyloxalyl hydroxamate (IpOHA) and aspterric acid are both potent inhibitors for both SaDHAD (Ki=7.8 and 51.6 μM, respectively) and CjDHAD (Ki=32.9 and 35.1 μM, respectively). These compounds thus present suitable starting points for the development of novel anti‐microbial chemotherapeutics.
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Affiliation(s)
- Tenuun Bayaraa
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
| | - Jose Gaete
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
| | - Samuel Sutiono
- Chair of Chemistry of Biogenic resources Campus Straubing for Biotechnology and Sustainability Technical University of Munich Schulgasse 16 94315 Straubing Germany
| | - Julia Kurz
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
| | - Thierry Lonhienne
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
| | - Jeffrey R. Harmer
- Centre for Advanced Imaging The University of Queensland Brisbane 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
| | - Volker Sieber
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
- Chair of Chemistry of Biogenic resources Campus Straubing for Biotechnology and Sustainability Technical University of Munich Schulgasse 16 94315 Straubing Germany
| | - Luke Guddat
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Australia
- Sustainable Minerals Institute The University of Queensland Brisbane 4072 Australia
- Australian Institute for Bioengineering and Nanotechnology The University of Queensland Brisbane 4072 Australia
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25
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Fort MJ, Click SM, Robinson EH, He FMC, Bernhardt PV, Rosenthal SJ, Macdonald JE. Minimizing the Reorganization Energy of Cobalt Redox Mediators Maximizes Charge Transfer Rates from Quantum Dots. Angew Chem Int Ed Engl 2022; 61:e202202322. [DOI: 10.1002/anie.202202322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Madeleine J. Fort
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Sophia M. Click
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Evan H. Robinson
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Felix M. C. He
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Sandra J. Rosenthal
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Janet E. Macdonald
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
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26
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Zapiter J, Harmer JR, Struwe M, Scheidig A, Clement B, Bernhardt PV. Enzyme Electrode Biosensors for N-Hydroxylated Prodrugs Incorporating the Mitochondrial Amidoxime Reducing Component. Anal Chem 2022; 94:9208-9215. [PMID: 35700342 DOI: 10.1021/acs.analchem.2c02232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human mitochondrial amidoxime reducing component 1 and 2 (mARC1 and mARC2) were immobilised on glassy carbon electrodes using the crosslinker glutaraldehyde. Voltammetry was performed in the presence of the artificial electron transfer mediator methyl viologen, whose redox potential lies negative of the enzymes' MoVI/V and MoV/IV redox potentials which were determined from optical spectroelectrochemical and EPR measurements. Apparent Michaelis constants obtained from catalytic limiting currents at various substrate concentrations were comparable to those previously reported in the literature from enzymatic assays. Kinetic parameters for benzamidoxime reduction were determined from cyclic voltammograms simulated using Digisim. pH dependence and stability of the enzyme electrode with time were also determined from limiting catalytic currents in saturating concentrations of benzamidoxime. The same electrode remained active after at least 9 days. Fabrication of this versatile and cost-effective biosensor is effective in screening new pharmaceutically important substrates and mARC inhibitors.
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Affiliation(s)
- Joan Zapiter
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, The University of Queensland, Brisbane 4072, Australia
| | - Michel Struwe
- Pharmazeutisches Institut, Universität Kiel, Gutenbergstraße 76, Kiel 24118, Germany.,Zoologisches Institut/Strukturbiologie, Am Botanischen Garten 11, Kiel 24118, Germany
| | - Axel Scheidig
- Zoologisches Institut/Strukturbiologie, Am Botanischen Garten 11, Kiel 24118, Germany
| | - Bernd Clement
- Pharmazeutisches Institut, Universität Kiel, Gutenbergstraße 76, Kiel 24118, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
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27
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Wu T, Salim AA, Khalil ZG, Bernhardt PV, Capon RJ. Glenthmycins A-M: Macrocyclic Spirotetronate Polyketide Antibacterials from the Australian Pasture Plant-Derived Streptomyces sp. CMB-PB041. J Nat Prod 2022; 85:1641-1657. [PMID: 35640100 DOI: 10.1021/acs.jnatprod.2c00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Chemical investigation of Australian pasture plant-derived Streptomyces sp. CMB-PB041, supported by miniaturized cultivation profiling and molecular network analysis, led to the isolation and characterization of 13 new macrocyclic spirotetronates, glenthmycins A-M (1-13), with structures assigned by detailed spectroscopic analysis, chemical degradation and derivatization, and mechanistic and biosynthetic considerations. Hydrolysis of glenthmycin B (2) yielded the aglycone 14, whose structure and absolute configuration were secured by X-ray analysis, along with the unexpected amino sugar residues glenthose lactams A (15) and B (16), with Mosher analysis of 15 facilitating assignment of absolute configurations of the amino sugar. While the glenthmycins proved to be acid stable, treatment of isomeric glenthmycins (i.e., 3, 6, and 8) with base catalyzed rapid intramolecular trans-esterification to regio-isomeric mixtures (i.e., 3 + 6 + 8). Exposure of 5 to base achieved the same intramolecular trans-esterification and was instrumental in detecting and tentatively identifying two additional minor co-metabolites, glenthmycins N (19) and O (20). A structure-activity relationship analysis carried out on 1-13 and the semisynthetic analogues 14 and 21-26 revealed a promising Gram +ve antibacterial pharmacophore, effective against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE), but with no detectable cytotoxicity to eukaryotic cells (i.e., fungal and human carcinoma). Of particular note, the semisynthetic analogue glenthmycin K 9-valerate (26) was unique among glenthmycins in potently inhibiting growth of the full panel of Gram +ve pathogens (IC50 0.2-1.6 μM). We conclude with an observation that any future evaluation of the antibacterial potential of glenthmycins and related macrocyclic spirotetronates may do well to include important soil-derived Gram +ve pathogens, such as Bacillus anthrax, Clostridium botulinum, and Rhodococcus equi, the causative agents of anthrax, botulism, and livestock pneumonia.
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Affiliation(s)
- Taizong Wu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Angela A Salim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zeinab G Khalil
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert J Capon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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28
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Fort MJ, Click SM, Robinson EH, He FMC, Bernhardt PV, Rosenthal SJ, Macdonald JE. Minimizing the Reorganization Energy of Cobalt Redox Mediators Maximizes Charge Transfer Rates from Quantum Dots. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Madeleine J. Fort
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Sophia M. Click
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Evan H. Robinson
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Felix M. C. He
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Sandra J. Rosenthal
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Janet E. Macdonald
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
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29
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Kalimuthu P, Harmer JR, Baldauf M, Hassan AH, Kruse T, Bernhardt PV. Electrochemically driven catalysis of the bacterial molybdenum enzyme YiiM. Biochim Biophys Acta Bioenerg 2022; 1863:148523. [PMID: 34921810 DOI: 10.1016/j.bbabio.2021.148523] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/18/2021] [Accepted: 12/07/2021] [Indexed: 12/20/2022]
Abstract
The Mo-dependent enzyme YiiM enzyme from Escherichia coli is a member of the sulfite oxidase family and shares many similarities with the well-studied human mitochondrial amidoxime reducing component (mARC). We have investigated YiiM catalysis using electrochemical and spectroscopic methods. EPR monitored redox potentiometry found the active site redox potentials to be MoVI/V -0.02 V and MoV/IV -0.12 V vs NHE at pH 7.2. In the presence of methyl viologen as an electrochemically reduced electron donor, YiiM catalysis was studied with a range of potential substrates. YiiM preferentially reduces N-hydroxylated compounds such as hydroxylamines, amidoximes, N-hydroxypurines and N-hydroxyureas but shows little or no activity against amine-oxides or sulfoxides. The pH optimum for catalysis was 7.1 and a bell-shaped pH profile was found with pKa values of 6.2 and 8.1 either side of this optimum that are associated with protonation/deprotonations that modulate activity. Simulation of the experimental voltammetry elucidated kinetic parameters associated with YiiM catalysis with the substrates 6-hydroxyaminopurine and benzamidoxime.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane, 4072, Australia
| | - Milena Baldauf
- Department of Plant Biology, Technische Universitaet Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Ahmed H Hassan
- Department of Plant Biology, Technische Universitaet Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Tobias Kruse
- Department of Plant Biology, Technische Universitaet Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia.
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30
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Wu T, Salim AA, Cui H, Khalil ZG, Bernhardt PV, Capon RJ. Glenthenamines A-F: Enamine Pyranonaphthoquinones from the Australian Pasture Plant Derived Streptomyces sp. CMB-PB042. J Nat Prod 2022; 85:337-344. [PMID: 35073486 DOI: 10.1021/acs.jnatprod.1c00821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Chemical investigations into solid phase cultivations of an Australian sheep station pasture plant derived Streptomyces sp. CMB-PB042 yielded the rare enamine naphthopyranoquinones BE-54238A (1) and BE-54238B (2), together with four new analogues, glenthenamines B-D (4-6) and F (8), and two handling artifacts, glenthenamines A (3) and E (7). Single-crystal X-ray analyses of 1 and 2 resolved configurational ambiguities in the scientific literature, while detailed spectroscopic analysis and biosynthetic considerations assigned structures inclusive of absolute configuration to 3-8. We propose a plausible sequence of biosynthetic transformations linking structural and configurational features of 1-8 and apply a novel Schiff base "fishing" approach to detect a key deoxyaminosugar precursor. These enamine naphthopyranoquinones disclose a new P-gp inhibitory pharmacophore capable of reversing doxorubicin resistance in P-gp overexpressing colon carcinoma cells.
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Affiliation(s)
- Taizong Wu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Angela A Salim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Hui Cui
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Zeinab G Khalil
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert J Capon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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31
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Fahrenhorst-Jones T, Bernhardt PV, Savage GP, Williams CM. The (±)-6-Aza[1.0]triblattane Skeleton: Contraction beyond the Wilder-Culberson Ring System. Org Lett 2022; 24:903-906. [PMID: 35043631 DOI: 10.1021/acs.orglett.1c04240] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthesis of the 6-aza[1.0]triblattane skeleton and the unexpected construction of the 7-azatetracyclo[4.2.1.02,5.03,7]nonane framework are reported, as inspired by the Wilder-Culberson 1-aza[1.1]triblattane ring system. The key steps to assess the 6-aza[1.0]triblattane include accessing the 1,6-cycloaddition product from reaction of chlorosulfonyl isocyanate with cyclohept-1,3,5-triene followed by intramolecular electrocyclization and aminium radical cyclization.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - G Paul Savage
- Ian Wark Laboratory, CSIRO Manufacturing, Melbourne, Victoria 3168, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
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32
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Podgorski MN, Harbort JS, Lee JHZ, Nguyen GT, Bruning JB, Donald WA, Bernhardt PV, Harmer JR, Bell SG. An Altered Heme Environment in an Engineered Cytochrome P450 Enzyme Enables the Switch from Monooxygenase to Peroxygenase Activity. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05877] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Matthew N. Podgorski
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Joshua S. Harbort
- Center for Advanced Imaging, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Joel H. Z. Lee
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Giang T.H. Nguyen
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - John B. Bruning
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - William A. Donald
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jeffrey R. Harmer
- Center for Advanced Imaging, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Stephen G. Bell
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
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33
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Gonzálvez MA, Su C, Williams CM, Bernhardt PV. Organocopper( ii) complexes: new catalysts for carbon–carbon bond formation via electrochemical atom transfer radical addition ( eATRA). Chem Sci 2022; 13:10506-10511. [PMID: 36277651 PMCID: PMC9473645 DOI: 10.1039/d2sc03418b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/17/2022] [Indexed: 11/21/2022] Open
Abstract
Electrochemical generation of a novel organocopper(ii) complex offers a new way to carry out atom transfer radical addition to alkenes under mild conditions with high yields and low catalyst loadings.
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Affiliation(s)
- Miguel A. Gonzálvez
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Chuyi Su
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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34
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Selyutina OY, Kononova PA, Koshman VE, Shelepova EA, Azad MG, Afroz R, Dharmasivam M, Bernhardt PV, Polyakov NE, Richardson DR. Ascorbate-and iron-driven redox activity of Dp44mT and emodin facilitates peroxidation of micelles and bicelles. Biochim Biophys Acta Gen Subj 2021; 1866:130078. [PMID: 34974127 DOI: 10.1016/j.bbagen.2021.130078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/10/2021] [Accepted: 12/20/2021] [Indexed: 12/28/2022]
Abstract
BACKGROUND Iron (Fe)-induced oxidative stress leads to reactive oxygen species that damage biomembranes, with this mechanism being involved in the activity of some anti-cancer chemotherapeutics. METHODS Herein, we compared the effect of Fe complexes of the ligand, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), or the potential ligand, Emodin, on lipid peroxidation in cell membrane models (micelles and bicelles). These studies were performed in the presence of hydrogen peroxide (H2O2) and the absence or presence of ascorbate. RESULTS In the absence of ascorbate, Fe(II)/Emodin mixtures incubated with H2O2 demonstrated slight pro-oxidant properties on micelles versus Fe(II) alone, while the Fe(III)-Dp44mT complex exhibited marked antioxidant properties. Examining more physiologically relevant phospholipid-containing bicelles, the Fe(II)- and Fe(III)-Dp44mT complexes demonstrated antioxidant activity without ascorbate. Upon adding ascorbate, there was a significant increase in the peroxidation of micelles and bicelles in the presence of unchelated Fe(II) and H2O2. The addition of ascorbate to Fe(III)-Dp44mT substantially increased the peroxidation of micelles and bicelles, with the Fe(III)-Dp44mT complex being reduced by ascorbate to the Fe(II) state, explaining the increased reactivity. Electron paramagnetic resonance spectroscopy demonstrated ascorbyl radical anion generation after mixing ascorbate and Emodin, with signal intensity being enhanced by H2O2. This finding suggested Emodin semiquinone radical formation that could play a role in its reactivity via ascorbate-driven redox cycling. Examining cultured melanoma cells in vitro, ascorbate at pharmacological levels enhanced the anti-proliferative activity of Dp44mT and Emodin. CONCLUSIONS AND GENERAL SIGNIFICANCE Ascorbate-driven redox cycling of Dp44mT and Emodin promotes their anti-proliferative activity.
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Affiliation(s)
- O Yu Selyutina
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090 Novosibirsk, Russia; Institute of Solid State Chemistry and Mechanochemistry, Kutateladze St., 18, 630128 Novosibirsk, Russia.
| | - P A Kononova
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090 Novosibirsk, Russia
| | - V E Koshman
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090 Novosibirsk, Russia
| | - E A Shelepova
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090 Novosibirsk, Russia
| | - M Gholam Azad
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
| | - R Afroz
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
| | - M Dharmasivam
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
| | - P V Bernhardt
- Department of Chemistry, University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - N E Polyakov
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090 Novosibirsk, Russia; Institute of Solid State Chemistry and Mechanochemistry, Kutateladze St., 18, 630128 Novosibirsk, Russia
| | - D R Richardson
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia; Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
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35
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Podgorski MN, Coleman T, Giang PD, Wang CR, Bruning JB, Bernhardt PV, De Voss JJ, Bell SG. To Be, or Not to Be, an Inhibitor: A Comparison of Azole Interactions with and Oxidation by a Cytochrome P450 Enzyme. Inorg Chem 2021; 61:236-245. [PMID: 34910500 DOI: 10.1021/acs.inorgchem.1c02786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cytochrome P450 (CYP) superfamily of heme monooxygenases is involved in a range of important chemical biotransformations across nature. Azole-containing molecules have been developed as drugs that bind to the heme center of these enzymes, inhibiting their function. The optical spectrum of CYP enzymes after the addition of these inhibitors is used to assess how the molecules bind. Here we use the bacterial CYP199A4 enzyme, from Rhodopseudomonas palustris HaA2, to compare how imidazolyl and triazolyl inhibitors bind to ferric and ferrous heme. 4-(Imidazol-1-yl)benzoic acid induced a red shift in the Soret wavelength (424 nm) in the ferric enzyme along with an increase and a decrease in the intensities of the δ and α bands, respectively. 4-(1H-1,2,4-Triazol-1-yl)benzoic acid binds to CYP199A4 with a 10-fold lower affinity and induces a smaller red shift in the Soret band. The crystal structures of CYP199A4 with these two inhibitors confirmed that these differences in the optical spectra were due to coordination of the imidazolyl ligand to the ferric Fe, but the triazolyl inhibitor interacts with, rather than displaces, the ferric aqua ligand. Additional water molecules were present in the active site of 4-(1H-1,2,4-triazol-1-yl)benzoic acid-bound CYP199A4. The space required to accommodate these additional water molecules in the active site necessitates changes in the position of the hydrophobic phenylalanine 298 residue. Upon reduction of the heme, the imidazole-based inhibitor Fe-N ligation was not retained. A 5-coordinate heme was also the predominant species in 4-(1H-1,2,4-triazol-1-yl)benzoic acid-bound ferrous CYP199A4, but there was an obvious shoulder at 447 nm indicative of some degree of Fe-N coordination. Rather than inhibit CYP199A4, 4-(imidazol-1-yl)benzoic acid was a substrate and was oxidized to generate a metabolite derived from ring opening of the imidazolyl ring: 4-[[2-(formylamino)acetyl]amino]benzoic acid.
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Affiliation(s)
- Matthew N Podgorski
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Tom Coleman
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Peter D Giang
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - C Ruth Wang
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - John B Bruning
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - James J De Voss
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Stephen G Bell
- Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
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36
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Gonzálvez MA, Bernhardt PV, Font-Bardia M, Gallen A, Jover J, Ferrer M, Martínez M. Molecular Approach to Alkali-Metal Encapsulation by a Prussian Blue Analogue Fe II/Co III Cube in Aqueous Solution: A Kineticomechanistic Exchange Study. Inorg Chem 2021; 60:18407-18422. [PMID: 34766767 PMCID: PMC8715505 DOI: 10.1021/acs.inorgchem.1c03001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The preparation of a series of alkali-metal inclusion complexes of the molecular cube [{CoIII(Me3-tacn)}4{FeII(CN)6}4]4- (Me3-tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane), a mixed-valent Prussian Blue analogue bearing bridging cyanido ligands, has been achieved by following a redox-triggered self-assembly process. The molecular cubes are extremely robust and soluble in aqueous media ranging from 5 M [H+] to 2 M [OH-]. All the complexes have been characterized by the standard mass spectometry, UV-vis, inductively coupled plasma, multinuclear NMR spectroscopy, and electrochemistry. Furthermore, X-ray diffraction analysis of the sodium and lithium salts has also been achieved, and the inclusion of moieties of the form {M-OH2}+ (M = Li, Na) is confirmed. These inclusion complexes in aqueous solution are rather inert to cation exchange and are characterized by a significant decrease in acidity of the confined water molecule due to hydrogen bonding inside the cubic cage. Exchange of the encapsulated cationic {M-OH2}+ or M+ units by other alkali metals has also been studied from a kineticomechanistic perspective at different concentrations, temperatures, ionic strengths, and pressures. In all cases, the thermal and pressure activation parameters obtained agree with a process that is dominated by differences in hydration of the cations entering and exiting the cage, although the size of the portal enabling the exchange also plays a determinant role, thus not allowing the large Cs+ cation to enter. All the exchange substitutions studied follow a thermodynamic sequence that relates with the size and polarizing capability of the different alkali cations; even so, the process can be reversed, allowing the entry of {Li-OH2}+ units upon adsorption of the cube on an anion exchange resin and subsequent washing with a Li+ solution.
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Affiliation(s)
- Miguel A Gonzálvez
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia.,Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mercè Font-Bardia
- Unitat de Difracció de Raigs, X. Centre Científic i Tecnològic,Departament de Cristal·lografia, and Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Albert Gallen
- Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Jesús Jover
- Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.,Institut de Química Teòrica i Computacional, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Montserrat Ferrer
- Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.,Institute of Nanoscience and Nanotechnology, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Manuel Martínez
- Secció de Química Inorgànica, Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.,Institute of Nanoscience and Nanotechnology, Universitat de Barcelona, 08028 Barcelona, Spain
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37
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Lim TX, Pierens GK, Bernhardt PV, Ahamed M, Reutens DC. Synthesis, isolation and characterisation of fluorinated-benzimidazoisoquinoline regioisomers. Magn Reson Chem 2021; 59:1154-1159. [PMID: 34250653 DOI: 10.1002/mrc.5193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/08/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
A pair of novel fluorinated-benzimidazoisoquinoline regioisomers was synthesised and isolated. Initial structural characterisation and identification employed 1D proton, 1D carbon, correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC) nuclear magnetic resonance spectroscopy and mass spectrometry. However, the fluorinated regioisomers could not be differentiated using nuclear magnetic resonance (NMR) alone. Density functional theory calculations and single-crystal X-ray diffraction experiments were used to completely characterise and identify the compounds.
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Affiliation(s)
- Ting Xiang Lim
- ARC Training Centre for Innovation in Biomedical Imaging Technology, Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
| | - Gregory K Pierens
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Muneer Ahamed
- ARC Training Centre for Innovation in Biomedical Imaging Technology, Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
| | - David C Reutens
- ARC Training Centre for Innovation in Biomedical Imaging Technology, Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
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38
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Connolly BJP, Brosius V, Mertes N, Demidova C, Bilyj JK, Riley MJ, Bernhardt PV. Temperature and Counterion Dependent Spin Crossover in a Hexaamineiron(II) Complex. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Blake J. P. Connolly
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Victor Brosius
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Nicole Mertes
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Caroline Demidova
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Jessica K. Bilyj
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Mark J. Riley
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
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39
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Song F, Yang N, Khalil ZG, Salim AA, Han J, Bernhardt PV, Lin R, Xu X, Capon RJ. Bhimamycin J, a Rare Benzo[f]isoindole-dione Alkaloid from the Marine-Derived Actinomycete Streptomyces sp. MS180069. Chem Biodivers 2021; 18:e2100674. [PMID: 34609053 DOI: 10.1002/cbdv.202100674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/04/2021] [Indexed: 11/12/2022]
Abstract
Chemical investigation on a Streptomyces sp. strain MS180069 isolated from a sediment sample collected from the South China Sea, yielded the new benzo[f]isoindole-dione alkaloid, bhimamycin J (1). The structure was determined by extensive spectroscopic analysis, including HRMS, 1D, 2D NMR, and X-ray diffraction techniques. A molecular docking study revealed 1 as a new molecular motif that binds with human angiotensin converting enzyme2 (ACE2), recently described as the cell surface receptor responsible for uptake of 2019-CoV-2. Using enzyme assays we confirm that 1 inhibits human ACE2 79.7 % at 25 μg/mL.
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Affiliation(s)
- Fuhang Song
- School of Light Industry, Beijing Technology and Business University, Beijing, 100048, P. R. China
| | - Na Yang
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, P. R. China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, P. R. China
| | - Zeinab G Khalil
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Angela A Salim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jiahui Han
- School of Ocean Sciences, China University of Geosciences, Beijing, 100083, P. R. China
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Rui Lin
- School of Ocean Sciences, China University of Geosciences, Beijing, 100083, P. R. China
| | - Xiuli Xu
- School of Ocean Sciences, China University of Geosciences, Beijing, 100083, P. R. China
| | - Robert J Capon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
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40
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Gonzaga de França Lopes L, Gouveia Júnior FS, Karine Medeiros Holanda A, Maria Moreira de Carvalho I, Longhinotti E, Paulo TF, Abreu DS, Bernhardt PV, Gilles-Gonzalez MA, Cirino Nogueira Diógenes I, Henrique Silva Sousa E. Bioinorganic systems responsive to the diatomic gases O2, NO, and CO: From biological sensors to therapy. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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41
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Blackman AG, Jelley RE, Krenske EH, Gahan LR, Bernhardt PV. Does H 3O + Really Act as a Ligand in the Solid State? Inorg Chem 2021; 60:13071-13079. [PMID: 34424671 DOI: 10.1021/acs.inorgchem.1c01485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The evidence for the existence of metal complexes containing H3O+ as a ligand in the solid state is examined. Each of the 68 examples in the Cambridge Structural Database in which H3O+ is bound to a transition metal, lanthanoid, actinoid, or main group metal ion is detailed and critically appraised. It is concluded that none of the reported examples of complexes containing coordinated H3O+ have been unequivocally characterized and that they result from either curation errors or misinterpretations of the crystallographic data. These conclusions are supported by computational techniques, which show that three purported H3O+ complexes based on the 1,4,7,10,13,16,21,24-octa-azabicyclo(8.8.8)hexacosane azacryptand skeleton are better described as aqua complexes, with protonation occurring at the amine ligand.
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Affiliation(s)
- Allan G Blackman
- Department of Chemistry, Centre for Biomedical and Chemical Sciences, School of Science, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand
| | - Rebecca E Jelley
- School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Elizabeth H Krenske
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Lawrence R Gahan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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42
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43
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Abstract
The rare organocopper(II) complex [Cu(Me6tren)(CH2CN)]+ (Me6tren = tris(2-(dimethylamino)ethyl)amine) has emerged as an important model of potential byproducts in copper-catalyzed atom transfer radical polymerization. This complex has been generated by controlled potential electrolysis of [Cu(Me6tren)(NCMe)]2+ in the presence of BrCH2CN. Time-resolved UV-vis and continuous wave and pulse electron paramagnetic resonance (EPR) spectra identified [Cu(Me6tren)Br]+ as an intermediate. Hyperfine sublevel correlation and electron nuclear double resonance spectroscopy of samples at different timepoints reveal signals that are assigned to a C-bound cyanomethylate ligand, with distinct 14N and 1H hyperfine coupling constants in comparison with the corresponding N-bound acetonitrile and bromido complexes. The experimental EPR data are supported by density functional theory calculations to understand how the geometries of the species involved produce distinct spectroscopic signatures, and a clear picture of how this unusual organocopper(II) complex is formed has emerged.
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Affiliation(s)
- Miguel A Gonzálvez
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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44
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Melville JN, Bernhardt PV. Electrochemical Exploration of Active Cu-Based Atom Transfer Radical Polymerization Catalysis through Ligand Modification. Inorg Chem 2021; 60:9709-9719. [PMID: 34142823 DOI: 10.1021/acs.inorgchem.1c01001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The intersection between Cu-catalyzed atom transfer radical polymerization (ATRP) and organometallic mediated radical polymerization (OMRP) has been recently shown to be a result of competition between the CuI and CuII complexes of polyamine ligands for the same organic free radical. The tetradentate ligands N,N'-bis-2'-pyridylmethyl-ethane-1,2-diamine (L1) and N,N'-dimethyl-N,N'-bis-2'-pyridylmethyl-ethane-1,2-diamine (L2) form stable Cu complexes which, depending on their oxidation state, can either liberate or complex organic radicals. Herein, we show that this process may be affected by subtle changes to the ligand system. Switching from a tertiary amine (L2) to a secondary amine (L1) retains ATRP and OMRP activity through a series of cyclic voltammetry measurements in the presence of the initiator bromoacetonitrile.
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Affiliation(s)
- Jamie N Melville
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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45
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Canavieira LM, Brasil EM, Silva TDME, Borges RDS, Silva JRA, Lameira J, Bernhardt PV, Williams CM, Alves CN. Experimental and theoretical approaches for the development of 4H-Chromene derivatives as inhibitors of tyrosinase. Molecular Simulation 2021. [DOI: 10.1080/08927022.2021.1926455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Luciana Morais Canavieira
- Programa de Pós-Graduação em Biotecnologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Edikarlos Macedo Brasil
- Peptide Science Laboratory, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Thiago de Melo e Silva
- Programa de Pós-Graduação em Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, Brazil
| | - Rosivaldo dos Santos Borges
- Núcleo de Estudos e Seleção de Moléculas Bioativas, Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém, Brazil
| | - José Rogério Araújo Silva
- Programa de Pós-Graduação em Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, Brazil
| | - Jerônimo Lameira
- Programa de Pós-Graduação em Biotecnologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
- Programa de Pós-Graduação em Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, Brazil
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Cláudio Nahum Alves
- Programa de Pós-Graduação em Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, Brazil
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46
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Struwe MA, Kalimuthu P, Luo Z, Zhong Q, Ellis D, Yang J, Khadanand KC, Harmer JR, Kirk ML, McEwan AG, Clement B, Bernhardt PV, Kobe B, Kappler U. Active site architecture reveals coordination sphere flexibility and specificity determinants in a group of closely related molybdoenzymes. J Biol Chem 2021; 296:100672. [PMID: 33887324 PMCID: PMC8166771 DOI: 10.1016/j.jbc.2021.100672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 11/27/2022] Open
Abstract
MtsZ is a molybdenum-containing methionine sulfoxide reductase that supports virulence in the human respiratory pathogen Haemophilus influenzae (Hi). HiMtsZ belongs to a group of structurally and spectroscopically uncharacterized S-/N-oxide reductases, all of which are found in bacterial pathogens. Here, we have solved the crystal structure of HiMtsZ, which reveals that the HiMtsZ substrate-binding site encompasses a previously unrecognized part that accommodates the methionine sulfoxide side chain via interaction with His182 and Arg166. Charge and amino acid composition of this side chain–binding region vary and, as indicated by electrochemical, kinetic, and docking studies, could explain the diverse substrate specificity seen in closely related enzymes of this type. The HiMtsZ Mo active site has an underlying structural flexibility, where dissociation of the central Ser187 ligand affected catalysis at low pH. Unexpectedly, the two main HiMtsZ electron paramagnetic resonance (EPR) species resembled not only a related dimethyl sulfoxide reductase but also a structurally unrelated nitrate reductase that possesses an Asp–Mo ligand. This suggests that contrary to current views, the geometry of the Mo center and its primary ligands, rather than the specific amino acid environment, is the main determinant of the EPR properties of mononuclear Mo enzymes. The flexibility in the electronic structure of the Mo centers is also apparent in two of three HiMtsZ EPR-active Mo(V) species being catalytically incompetent off-pathway forms that could not be fully oxidized.
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Affiliation(s)
- Michel A Struwe
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia; Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Zhenyao Luo
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, Australia
| | - Qifeng Zhong
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Daniel Ellis
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico, USA
| | - K C Khadanand
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico, USA
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Qld, Australia
| | - Martin L Kirk
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, Australia
| | - Alastair G McEwan
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Bernd Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia
| | - Bostjan Kobe
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, Australia
| | - Ulrike Kappler
- Australian Infectious Disease Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia.
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47
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Elbanna AH, Khalil ZG, Bernhardt PV, Capon RJ. Neobulgarones Revisited: Anti and Syn Bianthrones from an Australian Mud Dauber Wasp Nest-Associated Fungus, Penicillium sp. CMB-MD22. J Nat Prod 2021; 84:762-770. [PMID: 33534571 DOI: 10.1021/acs.jnatprod.0c01035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report on the chemical analysis of a mud dauber wasp nest-associated fungus, Penicillium sp. CMB-MD22, leading to the discovery and structure elucidation of three known (1-3) and two new (4 and 5) anthrones, and a family of new and known bianthrones, neobulgarones 6-23. Detection and structure elucidation of 1-23 was supported by detailed spectroscopic analysis, as well as chemical (thermal) transformations, and global natural products social (GNPS) molecular networking. An empirical approach using HPLC retention times was effective at differentiating anti from syn bianthrone isomers, while a facile thermal equilibration was shown to favor anti over syn isomers. The neobulgarones 6-23 are natural products, and a crude extract rich in 6-23 exhibits selective antifungal activity against a co-isolated mud dauber wasp nest-associated fungus, suggestive of a possible ecological role as an antifungal chemical defense.
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Affiliation(s)
- Ahmed H Elbanna
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zeinab G Khalil
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert J Capon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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48
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Abstract
Using a molecular networking guided strategy, chemical analysis of the Australian mullet fish gastrointestinal tract-derived fungus Amauroascus sp. CMB-F713 yielded a family of polyketide pyrones, amaurones A-I (1-9), featuring an unprecedented carbon skeleton. Structures were assigned to 1-9 by detailed spectroscopic analysis (including X-ray analysis of 1), biosynthetic considerations, and chemical interconversions. For example, the orthoacetate 5 was unstable when stored dry at room temperature, transforming to the monoacetates 2 and 3, while mild heating (40 °C) prompted quantitative conversion of 3 to 2, via an intramolecular trans-acetylation. Likewise, during handling, the monoacetate 1 was prone to intramolecular trans-acetylation, leading to an equilibrium mixture with the isomeric monoacetate amaurone J (10), confirmed when partial hydrolysis of the diacetate 2 yielded the monoacetates 1 and 10 and the triol amaurone K (11).
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Affiliation(s)
- Taizong Wu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Angela A Salim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert J Capon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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49
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Coleman T, Kirk AM, Chao RR, Podgorski MN, Harbort JS, Churchman LR, Bruning JB, Bernhardt PV, Harmer JR, Krenske EH, De Voss JJ, Bell SG. Understanding the Mechanistic Requirements for Efficient and Stereoselective Alkene Epoxidation by a Cytochrome P450 Enzyme. ACS Catal 2021. [DOI: 10.1021/acscatal.0c04872] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Tom Coleman
- Department of Chemistry, University Adelaide, Adelaide, South Australia 5005, Australia
| | - Alicia M. Kirk
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Rebecca R. Chao
- Department of Chemistry, University Adelaide, Adelaide, South Australia 5005, Australia
| | - Matthew N. Podgorski
- Department of Chemistry, University Adelaide, Adelaide, South Australia 5005, Australia
| | - Joshua S. Harbort
- Center for Advanced Imaging, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Luke R. Churchman
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - John B. Bruning
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jeffrey R. Harmer
- Center for Advanced Imaging, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Elizabeth H. Krenske
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - James J. De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Stephen G. Bell
- Department of Chemistry, University Adelaide, Adelaide, South Australia 5005, Australia
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Bilyj JK, Silajew NV, Bernhardt PV. Nickel coordination chemistry of bis(dithiocarbazate) Schiff base ligands; metal and ligand centred redox reactions. Dalton Trans 2021; 50:612-623. [PMID: 33320137 DOI: 10.1039/d0dt03204b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The tetradentate N2S2 Schiff base ligands derived from condensing S-methyl or S-benzyl dithiocarbazate with acetylacetone have been found to be versatile chelators for copper and able to stabilise unusually high oxidation states. Herein we report their Ni coordination chemistry and a variety of products ensue depending on the reaction conditions. Unusual examples of linkage isomerism have been observed upon complexation with nickel acetate and these asymmetrically and symmetrically coordinated NiIIN2S2 complexes have been characterised both crystallographically and in solution by NMR. These compounds react rapidly with dioxygen and the ligands are particularly susceptible to oxidation which lead to various products including dinuclear NiII complexes derived from radical homocoupling reactions. These dinuclear NiII complexes are also redox active and spectroelectrochemistry has revealed new electronic transitions from their formally NiIII/NiII mixed valent state.
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Affiliation(s)
- Jessica K Bilyj
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia.
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