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Lo Presti E, Schifano F, Bacchella C, Santagostini L, Casella L, Monzani E. Asymmetric Sulfoxidation by a Tyrosinase Biomimetic Dicopper Complex with a Benzimidazolyl Derivative of L-Phenylalanine. Molecules 2023; 28:molecules28114487. [PMID: 37298963 DOI: 10.3390/molecules28114487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
A challenge in mimicking tyrosinase activity using model compounds is to reproduce its enantioselectivity. Good enantioselection requires rigidity and a chiral center close to the active site. In this study, the synthesis of a new chiral copper complex, [Cu2(mXPhI)]4+/2+, based on an m-xylyl-bis(imidazole)-bis(benzimidazole) ligand containing a stereocenter with a benzyl residue directly bound on the copper chelating ring, is reported. Binding experiments show that the cooperation between the two metal centers is weak, probably due to steric hindrance given by the benzyl group. The dicopper(II) complex [Cu2(mXPhI)]4+ has catalytic activity in the oxidations of enantiomeric couples of chiral catechols, with an excellent discrimination capability for Dopa-OMe enantiomers and a different substrate dependence, hyperbolic or with substrate inhibition, for the L- or D- enantiomers, respectively. [Cu2(mXPhI)]4+ is active in a tyrosinase-like sulfoxidation of organic sulfides. The monooxygenase reaction requires a reducing co-substrate (NH2OH) and yields sulfoxide with significant enantiomeric excess (e.e.). Experiments with 18O2 and thioanisole yielded sulfoxide with 77% incorporation of 18O, indicating a reaction occurring mostly through direct oxygen transfer from the copper active intermediate to the sulfide. This mechanism and the presence of the chiral center of the ligand in the immediate copper coordination sphere are responsible for the good enantioselectivity observed.
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Affiliation(s)
- Eliana Lo Presti
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Fabio Schifano
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Chiara Bacchella
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Laura Santagostini
- Dipartimento di Chimica, Università di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Luigi Casella
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Enrico Monzani
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
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Koch A, Engesser TA, Tuczek F. Copper Complexes Supported by Iminotriazole Ligands: Effective Catalysts for the Monooxygenation of Phenols. Organometallics 2023. [DOI: 10.1021/acs.organomet.3c00014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Affiliation(s)
- Alexander Koch
- Institute of Inorganic Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Strasse 2, 24118 Kiel, Germany
| | - Tobias A. Engesser
- Institute of Inorganic Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Strasse 2, 24118 Kiel, Germany
| | - Felix Tuczek
- Institute of Inorganic Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Strasse 2, 24118 Kiel, Germany
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Schneider R, Engesser TA, Näther C, Krossing I, Tuczek F. Copper‐Catalyzed Monooxygenation of Phenols: Evidence for a Mononuclear Reaction Mechanism. Angew Chem Int Ed Engl 2022; 61:e202202562. [PMID: 35344617 PMCID: PMC9323449 DOI: 10.1002/anie.202202562] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Indexed: 11/17/2022]
Abstract
The CuI salts [Cu(CH3CN)4]PF and [Cu(oDFB)2]PF with the very weakly coordinating anion Al(OC(CF3)3)4− (PF) as well as [Cu(NEt3)2]PF comprising the unique, linear bis‐triethylamine complex [Cu(NEt3)2]+ were synthesized and examined as catalysts for the conversion of monophenols to o‐quinones. The activities of these CuI salts towards monooxygenation of 2,4‐di‐tert‐butylphenol (DTBP‐H) were compared to those of [Cu(CH3CN)4]X salts with “classic” anions (BF4−, OTf−, PF6−), revealing an anion effect on the activity of the catalyst and a ligand effect on the reaction rate. The reaction is drastically accelerated by employing CuII‐semiquinone complexes as catalysts, indicating that formation of a CuII complex precedes the actual catalytic cycle. This result and other experimental observations show that with these systems the oxygenation of monophenols does not follow a dinuclear, but a mononuclear pathway analogous to that of topaquinone cofactor biosynthesis in amine oxidase.
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Affiliation(s)
- Rebecca Schneider
- Institut für Anorganische Chemie Christian-Albrechts-Universität zu Kiel Max-Eyth-Straße 2 24118 Kiel Germany
| | - Tobias A. Engesser
- Institut für Anorganische Chemie Christian-Albrechts-Universität zu Kiel Max-Eyth-Straße 2 24118 Kiel Germany
| | - Christian Näther
- Institut für Anorganische Chemie Christian-Albrechts-Universität zu Kiel Max-Eyth-Straße 2 24118 Kiel Germany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie Albert-Ludwigs-Universität Freiburg Albertstraße 21 79104 Freiburg Germany
| | - Felix Tuczek
- Institut für Anorganische Chemie Christian-Albrechts-Universität zu Kiel Max-Eyth-Straße 2 24118 Kiel Germany
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Schneider R, Engesser TA, Näther C, Krossing I, Tuczek F. Copper‐Catalyzed Monooxygenation of Phenols: Evidence for a Mononuclear Reaction Mechanism. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rebecca Schneider
- Christian-Albrechts-Universität zu Kiel: Christian-Albrechts-Universitat zu Kiel Institute for Inorganic Chemistry Max-Eyth-Straße 2 24118 Kiel GERMANY
| | - Tobias A. Engesser
- Christian-Albrechts-Universitat zu Kiel Institut für Anorganische Chemie Otto-Hahn-Platz 10 24118 Kiel GERMANY
| | - Christian Näther
- Christian-Albrechts-Universität zu Kiel: Christian-Albrechts-Universitat zu Kiel Institute for Inorganic Chemistry Max-Eyth-Straße 2 24118 Kiel GERMANY
| | - Ingo Krossing
- University of Freiburg: Albert-Ludwigs-Universitat Freiburg Institute for Inorganic and Analytical Chemistry Albertstr. 21 79104 Freiburg i. Br. GERMANY
| | - Felix Tuczek
- Christian-Albrechts-Universität zu Kiel: Christian-Albrechts-Universitat zu Kiel Institute for Inorganic Chemistry Max-Eyth-Straße 2 24118 Kiel GERMANY
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Bacchella C, Gentili S, Bellotti D, Quartieri E, Draghi S, Baratto MC, Remelli M, Valensin D, Monzani E, Nicolis S, Casella L, Tegoni M, Dell'Acqua S. Binding and Reactivity of Copper to R 1 and R 3 Fragments of tau Protein. Inorg Chem 2019; 59:274-286. [PMID: 31820933 DOI: 10.1021/acs.inorgchem.9b02266] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Tau protein is present in significant amounts in neurons, where it contributes to the stabilization of microtubules. Insoluble neurofibrillary tangles of tau are associated with several neurological disorders known as tauopathies, among which is Alzheimer's disease. In neurons, tau binds tubulin through its microtubule binding domain which comprises four imperfect repeats (R1-R4). The histidine residues contained in these fragments are potential binding sites for metal ions and are located close to the regions that drive the formation of amyloid aggregates of tau. In this study, we present a detailed characterization through potentiometric and spectroscopic methods of the binding of copper in both oxidation states to R1 and R3 peptides, which contain one and two histidine residues, respectively. We also evaluate how the redox cycling of copper bound to tau peptides can mediate oxidation that can potentially target exogenous substrates such as neuronal catecholamines. The resulting quinone oxidation products undergo oligomerization and can competitively give post-translational peptide modifications yielding catechol adducts at amino acid residues. The presence of His-His tandem in the R3 peptide strongly influences both the binding of copper and the reactivity of the resulting copper complex. In particular, the presence of the two adjacent histidines makes the copper(I) binding to R3 much stronger than in R1. The copper-R3 complex is also much more active than the copper-R1 complex in promoting oxidative reactions, indicating that the two neighboring histidines activate copper as a catalyst in molecular oxygen activation reactions.
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Affiliation(s)
- Chiara Bacchella
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Silvia Gentili
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale , Università di Parma , Parco Area delle Scienze 11/A , 43124 Parma , Italy
| | - Denise Bellotti
- Dipartimento di Scienze Chimiche e Farmaceutiche , Università di Ferrara , Via Luigi Borsari 46 , 44121 Ferrara , Italy
| | - Eleonora Quartieri
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale , Università di Parma , Parco Area delle Scienze 11/A , 43124 Parma , Italy
| | - Sara Draghi
- Dipartimento di Biotecnologie, Chimica e Farmacia , Università di Siena , Via A. Moro 2 , 53100 , Siena , Italy
| | - Maria Camilla Baratto
- Dipartimento di Biotecnologie, Chimica e Farmacia , Università di Siena , Via A. Moro 2 , 53100 , Siena , Italy
| | - Maurizio Remelli
- Dipartimento di Scienze Chimiche e Farmaceutiche , Università di Ferrara , Via Luigi Borsari 46 , 44121 Ferrara , Italy
| | - Daniela Valensin
- Dipartimento di Biotecnologie, Chimica e Farmacia , Università di Siena , Via A. Moro 2 , 53100 , Siena , Italy
| | - Enrico Monzani
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Stefania Nicolis
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Luigi Casella
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Matteo Tegoni
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale , Università di Parma , Parco Area delle Scienze 11/A , 43124 Parma , Italy
| | - Simone Dell'Acqua
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
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Presti EL, Perrone ML, Santagostini L, Casella L, Monzani E. A Stereoselective Tyrosinase Model Compound Derived from an m-Xylyl-l-histidine Ligand. Inorg Chem 2019; 58:7335-7344. [PMID: 31091087 DOI: 10.1021/acs.inorgchem.9b00473] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The aim of mimicking enzyme activity represents an important motivation for the development of new catalysts. A challenging objective is the development of chiral complexes for bioinspired enantioselective oxidation reactions. Herein, we report a new chiral dinuclear copper(II) complex based on a m-xylyl-bis(histidine) ligand (mXHI) as a biomimetic catalyst for tyrosinase and catechol oxidase. The new ligand improves a previous system also containing two tridentate N3 units derived from l-histidine that were connected by a short, rigid ethanediamine bridge. In mXHI the bridge is provided by the more extended m-xylyl moiety. The dicopper(II) complex [Cu2(mXHI)]4+ was studied as a catalyst for stereoselective oxidations of enantiomeric couples of chiral catechols of biological interest (L/D-dopa, L/D-dopa methyl ester, and ( R/ S)-norepinephrine), showing excellent discrimination capability, particularly for the methyl esters of dopa enantiomers. The catechol oxidation was studied in acetate buffer as slightly acidic medium, and a role of acetate as bridging ligand between the two coppers, preorganizing the dinuclear center in a more catalytic efficient structure, could be established. The oxidation of β-naphthol and 3,5-ditertbutylphenol was studied as a model monophenolase reaction. The oxidation proceeds stoichiometrically, and the partial incorporation of 18O into β-naphthol when the reaction was performed using 18O2 suggests the existence of two competitive reaction pathways, a genuine monooxygenase mechanism and a radical pathway. However, the more challenging reaction on derivatives of l-/d-tyrosine did not lead to the desired monooxygenase product but only to products of radical oxidation. Complex [Cu2(mXHI)]4+ was also used for the catalytic sulfoxidation of thioanisole in the presence of hydroxylamine as cosubstrate, in a preliminary attempt to model the reaction of external monooxygenases. The reaction proceeds with 25 turnovers, but the enantiomeric excess of sulfoxide was modest.
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Affiliation(s)
- Eliana Lo Presti
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Maria L Perrone
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Laura Santagostini
- Dipartimento di Chimica , Università di Milano , Via Golgi 19 , 20133 Milano , Italy
| | - Luigi Casella
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Enrico Monzani
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
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Huang X, Li K, Wang X, Xia P. Rational design of an "on-off-on" fluorescent switch for Cu 2+ and histidine based on chiral macrocyclic dioxopolyamine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 205:287-291. [PMID: 30029191 DOI: 10.1016/j.saa.2018.07.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 06/08/2023]
Abstract
A novel chemosensor 1 having a chiral macrocyclic dioxopolyamine of C2 symmetry as a receptor and anthracene as a signal unit has been designed and synthesized for cations and α-amino acids recognition in DMSO-HEPES buffer (1:9, v/v, pH 7.2). The ligand exhibited selective response to Cu2+ even in the presence of other metal ions with a fluorescence "switch-off" behavior. Additionally, the in situ generated 1-Cu2+ ensemble displayed specific recognition to histidine by a "switch-on" fluorescence response. For this dual functional switch, its sensing behavior via a displacement mode was confirmed by 1H NMR titration and ESI mass spectroscopy. Sequential "on-off-on" fluorescence responses of 1 to Cu2+ and histidine are successfully applied in HeLa cells.
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Affiliation(s)
- Xiaohuan Huang
- Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, PR China.
| | - Kaiqun Li
- Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, PR China
| | - Xu Wang
- Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, PR China
| | - Peng Xia
- Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, PR China
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Presti EL, Monzani E, Santagostini L, Casella L. Building biomimetic model compounds of dinuclear and trinuclear copper clusters for stereoselective oxidations. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.09.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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