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Zeppilli D, Madabeni A, Nogara PA, Rocha JBT, Orian L. Reactivity of Zinc Fingers in Oxidizing Environments: Insight from Molecular Models Through Activation Strain Analysis. Chempluschem 2024:e202400252. [PMID: 38842473 DOI: 10.1002/cplu.202400252] [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: 04/05/2024] [Revised: 06/06/2024] [Accepted: 06/06/2024] [Indexed: 06/07/2024]
Abstract
The reactivity of Zn2+ tetrahedral complexes with H2O2 was investigated in silico, as a first step in their disruption process. The substrates were chosen to represent the cores of three different zinc finger protein motifs, i. e., a Zn2+ ion coordinated to four cysteines (CCCC), to three cysteines and one histidine (CCCH), and to two cysteines and two histidines (CCHH). The cysteine and histidine ligands were further simplified to methyl thiolate and imidazole, respectively. H2O2 was chosen as an oxidizing agent due to its biological role as a metabolic product and species involved in signaling processes. The mechanism of oxidation of a coordinated cysteinate to sulfenate-κS and the trends for the different substrates were rationalized through activation strain analysis and energy decomposition analysis in the framework of scalar relativistic Density Functional Theory (DFT) calculations at ZORA-M06/TZ2P ae // ZORA-BLYP-D3(BJ)/TZ2P. CCCC is oxidized most easily, an outcome explained considering both electrostatic and orbital interactions. The isomerization to sulfenate-κO was attempted to assess whether this step may affect the ligand dissociation; however, it was found to introduce a kinetic barrier without improving the energetics of the dissociation. Lastly, ligand exchange with free thiolates and selenolates was investigated as a trigger for ligand dissociation, possibly leading to metal ejection; molecular docking simulations also support this hypothesis.
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Affiliation(s)
- Davide Zeppilli
- Dipartimento di Scienze Chimiche Università degli Studi di Padova, Via Marzolo 1, 35131, Padova, Italy
| | - Andrea Madabeni
- Dipartimento di Scienze Chimiche Università degli Studi di Padova, Via Marzolo 1, 35131, Padova, Italy
| | - Pablo A Nogara
- Departamento de Bioquímica e Biologia Molecolar, Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil
- Instituto Federal de Educação, Ciência e Tecnologia Sul-rio-grandense (IFSul), Av. Leonel de Moura Brizola, 2501, 96418-400, Bagé, RS, Brasil
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecolar, Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil
| | - Laura Orian
- Dipartimento di Scienze Chimiche Università degli Studi di Padova, Via Marzolo 1, 35131, Padova, Italy
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Barbosa NV, Aschner M, Tinkov AA, Farina M, da Rocha JBT. Should ebselen be considered for the treatment of mercury intoxication? A minireview. Toxicol Mech Methods 2024; 34:1-12. [PMID: 37731353 PMCID: PMC10841883 DOI: 10.1080/15376516.2023.2258958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 09/09/2023] [Indexed: 09/22/2023]
Abstract
Mercury is a ubiquitous environmental contaminant and can be found in inorganic (Hg0, Hg+ and Hg2+) and organic forms (chiefly CH3Hg+ or MeHg+). The main route of human, mammals and bird exposure occurs via predatory fish ingestion. Occupational exposure to Hg0 (and Hg2+) can also occur; furthermore, in gold mining areas the exposure to inorganic Hg can also be high. The toxicity of electrophilic forms of Hg (E+Hg) is mediated by disruption of thiol (-SH)- or selenol (-SeH)-containing proteins. The therapeutic approaches to treat methylmercury (MeHg+), Hg0 and Hg2+ are limited. Here we discuss the potential use of ebselen as a potential therapeutic agent to lower the body burden of Hg in man. Ebselen is a safe drug for humans and has been tested in clinical trials (for instance, brain ischemia, noise-induce hearing loss, diabetes complications, bipolar disorders) at doses varying from 400 to 3600 mg per day. Two clinical trials with ebselen in moderate and severe COVID are also approved. Ebselen can be metabolized to an intermediate with -SeH (selenol) functional group, which has a greater affinity to electrophilic Hg (E+Hg) forms than the available thiol-containing therapeutic agents. Accordingly, as observed in vitro and rodent models in vivo, Ebselen exhibited protective effects against MeHg+, indicating its potential as a therapeutic agent to treat MeHg+ overexposure. The combined use of ebselen with thiol-containing molecules (e.g. N-acetylcysteine and enaramide)) is also commented, because they can have synergistic protective effects against MeHg+.
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Affiliation(s)
- Nilda V. Barbosa
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Alexey A. Tinkov
- Yaroslavl State University, Yaroslavl, Russia
- Center of Bioelementology and Human Ecology, IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - João Batista Teixeira da Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil
- Departamento de Bioquímica, Instituto Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Takanezawa Y, Ishikawa K, Nakayama S, Nakamura R, Ohshiro Y, Uraguchi S, Kiyono M. Conversion of methylmercury into inorganic mercury via organomercurial lyase (MerB) activates autophagy and aggresome formation. Sci Rep 2023; 13:19958. [PMID: 37968352 PMCID: PMC10651920 DOI: 10.1038/s41598-023-47110-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/09/2023] [Indexed: 11/17/2023] Open
Abstract
Methylmercury (MeHg) is converted to inorganic mercury (iHg) in several organs; however, its impact on tissues and cells remains poorly understood. Previously, we established a bacterial organomercury lyase (MerB)-expressing mammalian cell line to overcome the low cell permeability of iHg and investigate its effects. Here, we elucidated the cytotoxic effects of the resultant iHg on autophagy and deciphered their relationship. Treatment of MerB-expressing cells with MeHg significantly increases the mRNA and protein levels of LC3B and p62, which are involved in autophagosome formation and substrate recognition, respectively. Autophagic flux assays using the autophagy inhibitor chloroquine (CQ) revealed that MeHg treatment activates autophagy in MerB-expressing cells but not in wild-type cells. Additionally, MeHg treatment induces the accumulation of ubiquitinated proteins and p62, specifically in MerB-expressing cells. Confocal microscopy revealed that large ubiquitinated protein aggregates (aggresomes) associated with p62 are formed transiently in the perinuclear region of MerB-expressing cells upon MeHg exposure. Meanwhile, inhibition of autophagic flux decreases the MeHg-induced cell viability of MerB-expressing cells. Overall, our results imply that cells regulate aggresome formation and autophagy activation by activating LC3B and p62 to prevent cytotoxicity caused by iHg. These findings provide insights into the role of autophagy against iHg-mediated toxicity.
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Affiliation(s)
- Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Kouhei Ishikawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Shunsuke Nakayama
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Yuka Ohshiro
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan.
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Reactivity and binding mode of disulfiram, its metabolites, and derivatives in SARS-CoV-2 PL pro: insights from computational chemistry studies. J Mol Model 2022; 28:354. [PMID: 36222962 PMCID: PMC9554863 DOI: 10.1007/s00894-022-05341-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 09/28/2022] [Indexed: 10/25/2022]
Abstract
The papain-like protease (PLpro) from SARS-CoV-2 is an important target for the development of antivirals against COVID-19. The safe drug disulfiram (DSF) presents antiviral activity inhibiting PLpro in vitro, and it is under clinical trial studies, indicating to be a promising anti-COVID-19 drug. In this work, we aimed to understand the mechanism of PLpro inhibition by DSF and verify if DSF metabolites and derivatives could be potential inhibitors too. Molecular docking, DFT, and ADMET techniques were applied. The carbamoylation of the active site cysteine residue by DSF metabolite (DETC-MeSO) is kinetically and thermodynamically favorable (ΔG‡ = 3.15 and ΔG = - 12.10 kcal mol-1, respectively). Our results strongly suggest that the sulfoxide metabolites from DSF are promising covalent inhibitors of PLpro and should be tested in in vitro and in vivo assays to confirm their antiviral action.
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Madabeni A, Zucchelli S, Nogara PA, Rocha JBT, Orian L. In the Chalcogenoxide Elimination Panorama: Systematic Insight into a Key Reaction. J Org Chem 2022; 87:11766-11775. [PMID: 35951408 PMCID: PMC9442651 DOI: 10.1021/acs.joc.2c01454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The selenoxide elimination is a well-known reaction in
organochalcogen
chemistry, with wide synthetic, biological, and toxicological implications.
In this work, we apply benchmarked density functional theory (DFT)
calculations to investigate different aspects of the title reaction
in three (bio)chemically relevant models, spanning minimal systems
of theoretical interests as well as biological or synthetic organochalcogenides.
The activation strain analysis (ASA) methodology is employed along
a suitable reaction coordinate to obtain insight into the role of
the chalcogen and of the oxidation state, to pinpoint the factors
that tune the elimination reactivity of the investigated systems.
Lastly, we computationally validate the hypothesis that telluroxides
eliminate more slowly than selenoxides because of a detrimental hydration
process that leads to unreactive hydrates.
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Affiliation(s)
- Andrea Madabeni
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Simone Zucchelli
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Pablo A Nogara
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria (UFSM), Santa Maria, 97105-900, RS, Brazil
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria (UFSM), Santa Maria, 97105-900, RS, Brazil
| | - Laura Orian
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
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Orian L, Flohé L. Selenium-Catalyzed Reduction of Hydroperoxides in Chemistry and Biology. Antioxidants (Basel) 2021; 10:1560. [PMID: 34679695 PMCID: PMC8533274 DOI: 10.3390/antiox10101560] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/06/2021] [Accepted: 09/28/2021] [Indexed: 01/23/2023] Open
Abstract
Among the chalcogens, selenium is the key element for catalyzed H2O2 reduction. In organic synthesis, catalytic amounts of organo mono- and di-selenides are largely used in different classes of oxidations, in which H2O2 alone is poorly efficient. Biological hydroperoxide metabolism is dominated by peroxidases and thioredoxin reductases, which balance hydroperoxide challenge and contribute to redox regulation. When their selenocysteine is replaced by cysteine, the cellular antioxidant defense system is impaired. Finally, classes of organoselenides have been synthesized with the aim of mimicking the biological strategy of glutathione peroxidases, but their therapeutic application has so far been limited. Moreover, their therapeutic use may be doubted, because H2O2 is not only toxic but also serves as an important messenger. Therefore, over-optimization of H2O2 reduction may lead to unexpected disturbances of metabolic regulation. Common to all these systems is the nucleophilic attack of selenium to one oxygen of the peroxide bond promoting its disruption. In this contribution, we revisit selected examples from chemistry and biology, and, by using results from accurate quantum mechanical modelling, we provide an accurate unified picture of selenium's capacity of reducing hydroperoxides. There is clear evidence that the selenoenzymes remain superior in terms of catalytic efficiency.
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Affiliation(s)
- Laura Orian
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, 35131 Padova, Italy
| | - Leopold Flohé
- Dipartimento di Medicina Molecolare, Università degli Studi di Padova, 35121 Padova, Italy
- Departamento de Bioquimica, Universidad de la Republica, Montevideo 11800, Uruguay
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