1
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Ciardullo G, Orlando C, Russo N, Marchese E, Galano A, Marino T, Prejanò M. On the dual role of (+)-catechin as primary antioxidant and inhibitor of viral proteases. Comput Biol Med 2024; 180:108953. [PMID: 39089115 DOI: 10.1016/j.compbiomed.2024.108953] [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: 05/10/2024] [Revised: 07/17/2024] [Accepted: 07/26/2024] [Indexed: 08/03/2024]
Abstract
Natural antioxidants have become the subject of many investigations due to the role that they play in the reduction of oxidative stress. Their main scavenging mechanisms concern the direct inactivation of free radicals and the coordination of metal ions involved in Fenton-like reactions. Recently, increasing attention has been paid to non-covalent inhibition of enzymes involved in different diseases by the antioxidants. Here, a computational investigation on the primary antioxidant power of (+)-catechin against the •OOH radical has been performed in both lipid-like and aqueous environments, taking into account the relevant species present in the simulated acid-base equilibria at the physiological pH. Hydrogen Atom Transfer (HAT), Single Electron Transfer (SET), and Radical Adduct Formation (RAF) mechanisms were studied, and relative rate constants were estimated. The potential inhibitory activity of the (+)-catechin towards the most important proteases from SARS-CoV-2, 3C-like (Mpro) and papain-like (PLpro) proteases was also investigated by MD simulations to provide deeper atomistic insights on the binding sites. Based on the antioxidant and antiviral properties also unravelled by comparison with other molecules having similar chemical scaffold, our results propose that (+)-CTc satisfies can explicate a dual action as antioxidant and antiviral in particular versus Mpro from SARS-CoV-2.
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Affiliation(s)
- Giada Ciardullo
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Rende, (CS), Italy
| | - Carla Orlando
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Rende, (CS), Italy
| | - Nino Russo
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Rende, (CS), Italy
| | - Emanuela Marchese
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Rende, (CS), Italy
| | - Annia Galano
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Ciudad de México, 09310, Mexico
| | - Tiziana Marino
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Rende, (CS), Italy.
| | - Mario Prejanò
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Rende, (CS), Italy
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2
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Kaur R, Frederickson A, Wetmore SD. Elucidation of the catalytic mechanism of a single-metal dependent homing endonuclease using QM and QM/MM approaches: the case study of I- PpoI. Phys Chem Chem Phys 2024; 26:8919-8931. [PMID: 38426850 DOI: 10.1039/d3cp06201e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Homing endonucleases (HEs) are highly specific DNA cleaving enzymes, with I-PpoI having been suggested to use a single metal to accelerate phosphodiester bond cleavage. Although an I-PpoI mechanism has been proposed based on experimental structural data, no consensus has been reached regarding the roles of the metal or key active site amino acids. This study uses QM cluster and QM/MM calculations to provide atomic-level details of the I-PpoI catalytic mechanism. Minimal QM cluster and large-scale QM/MM models demonstrate that the experimentally-proposed pathway involving direct Mg2+ coordination to the substrate coupled with leaving group protonation through a metal-activated water is not feasible due to an inconducive I-PpoI active site alignment. Despite QM cluster models of varying size uncovering a pathway involving leaving group protonation by a metal-activated water, indirect (water-mediated) metal coordination to the substrate is required to afford this pathway, which renders this mechanism energetically infeasible. Instead, QM cluster models reveal that the preferred pathway involves direct Mg2+-O3' coordination to stabilize the charged substrate and assist leaving group departure, while H98 activates the water nucleophile. These calculations also underscore that both catalytic residues that directly interact with the substrate and secondary amino acids that position or stabilize these residues are required for efficient catalysis. QM/MM calculations on the solvated enzyme-DNA complex verify the preferred mechanism, which is fully consistent with experimental kinetic, structural, and mutational data. The fundamental understanding of the I-PpoI mechanism of action, gained from the present work can be used to further explore potential uses of this enzyme in biotechnology and medicine, and direct future computational investigations of other members of the understudied HE family.
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Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
| | - Angela Frederickson
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
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3
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Orlando C, Prejanò M, Russo N, Marino T. On the Role of Temperature in the Depolymerization of PET by FAST-PETase: An Atomistic Point of View on Possible Active Site Pre-Organization and Substrate-Destabilization Effects. Chembiochem 2023; 24:e202300412. [PMID: 37556192 DOI: 10.1002/cbic.202300412] [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: 06/21/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/10/2023]
Abstract
Enzyme FAST-PETase, recently obtained by a machine learning approach, can depolymerize poly(ethylene terephthalate) (PET), a synthetic resin employed in plastics and in clothing fibers. Therefore it represents a promising solution for the recycling of PET-based materials. In this study, a model of PET was adopted to describe the substrate, and all-atoms classical molecular dynamics (MD) simulations on apo- and substrate-bound FAST-PETase were carried out at 30 and 50 °C to provide atomistic details on the binding step of the catalytic cycle. Comparative analysis shed light on the interactions occurring between the FAST-PETase and 4PET at 50 °C, the optimal working conditions of the enzyme. Pre-organization of the enzyme active and binding sites has been highlighted, while MD simulations of FAST-PETase:4PET pointed out the occurrence of solvent-inaccessible conformations of the substrate promoted by the enzyme. Indeed, neither of these conformations was observed during MD simulations of the substrate alone in solution performed at 30, 50 and 150 °C. The analysis led us to propose that, at 50 °C, the FAST-PETase is pre-organized to bind the PET and that the interactions occurring in the binding site can promote a more reactive conformation of PET substrate, thus enhancing the catalytic activity of the enzyme.
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Affiliation(s)
- Carla Orlando
- Dipartimento di Chimica e Tecnologie Chimiche Laboratorio PROMOCS cubo 14C, Università della Calabria, 87036, Rende (CS), Italy
| | - Mario Prejanò
- Dipartimento di Chimica e Tecnologie Chimiche Laboratorio PROMOCS cubo 14C, Università della Calabria, 87036, Rende (CS), Italy
| | - Nino Russo
- Dipartimento di Chimica e Tecnologie Chimiche Laboratorio PROMOCS cubo 14C, Università della Calabria, 87036, Rende (CS), Italy
| | - Tiziana Marino
- Dipartimento di Chimica e Tecnologie Chimiche Laboratorio PROMOCS cubo 14C, Università della Calabria, 87036, Rende (CS), Italy
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4
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Uranga J, Rabe von Pappenheim F, Tittmann K, Mata RA. Dynamic Protonation States Underlie Carbene Formation in ThDP-Dependent Enzymes: A Theoretical Study. J Phys Chem B 2023; 127. [PMID: 37748048 PMCID: PMC10688766 DOI: 10.1021/acs.jpcb.3c03137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/09/2023] [Indexed: 09/27/2023]
Abstract
The activation mechanism of thiamine diphosphate (ThDP) in enzymes has long been the subject of intense research and controversial discussion. Particularly contentious is the formation of a carbene intermediate, the first one observed in an enzyme. For the formation of the carbene to take place, both intramolecular and intermolecular proton transfer pathways have been proposed. However, the physiologically relevant pH of ThDP-dependent enzymes around neutrality does not seem to be suitable for the formation of such reactive chemical species. Herein, we investigate the general mechanism of activation of the ThDP cofactor in human transketolase (TKT), by means of electronic structure methods. We show that in the case of the human TKT, the carbene species is accessible through a pKa shift induced by the electrostatics of a neighboring histidine residue (H110), whose protonation state change modulates the pKa of ThDP and suppresses the latter by more than 6 pH units. Our findings highlight that ThDP enzymes activate the cofactor beyond simple geometric constraints and the canonical glutamate. Such observations in nature can pave the way for the design of biomimetic carbene catalysts and the engineering of tailored enzymatic carbenes.
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Affiliation(s)
- Jon Uranga
- Institute
of Physical Chemistry, Georg-August Universität
Göttingen, Tammannstraße 6, 37077 Göttingen, Germany
| | - Fabian Rabe von Pappenheim
- Department
of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August Universität Göttingen, Julia-Lermonotowa-Weg 3, D-37077 Göttingen, Germany
| | - Kai Tittmann
- Department
of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August Universität Göttingen, Julia-Lermonotowa-Weg 3, D-37077 Göttingen, Germany
- Department
of Physical Biochemistry, Max-Planck-Institute
for Multidisciplinary Natural Sciences, Am Faßberg 11, D-37077 Göttingen, Germany
| | - Ricardo A. Mata
- Institute
of Physical Chemistry, Georg-August Universität
Göttingen, Tammannstraße 6, 37077 Göttingen, Germany
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5
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Beagan DM, Kiernicki JJ, Zeller M, Szymczak NK. A Bidentate Ligand Featuring Ditopic Lewis Acids in the Second Sphere for Selective Substrate Capture and Activation. Angew Chem Int Ed Engl 2023; 62:e202218907. [PMID: 36720708 PMCID: PMC10023486 DOI: 10.1002/anie.202218907] [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: 12/21/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/02/2023]
Abstract
We present a ligand platform featuring appended ditopic Lewis acids to facilitate capture/activation of diatomic substrates. We show that incorporation of two 9-borabicyclo[3.3.1]nonane (9-BBN) units on a single carbon tethered to a pyridine pyrazole scaffold maintains a set of unquenched nitrogen donors available to coordinate FeII , ZnII , and NiII . Using hydride ion affinity and competition experiments, we establish an additive effect for ditopic secondary sphere boranes, compared to the monotopic analogue. These effects are exploited to achieve high selectivity for binding NO2 - in the presence of competitive anions such as F- and NO3 - . Finally, we demonstrate hydrazine capture within the second-sphere of metal complexes, followed by unique activation pathways to generate hydrazido and diazene ligands on Zn and Fe, respectively.
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Affiliation(s)
- Daniel M Beagan
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109, USA
| | - John J Kiernicki
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109, USA
- Present address: Drury University, Department of Chemistry and Physics, 900 North Benton Ave., Springfield, MO 65802, USA
| | - Matthias Zeller
- H.C. Brown Laboratory, Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA
| | - Nathaniel K Szymczak
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109, USA
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6
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Kaur R, Nikkel DJ, Aboelnga MM, Wetmore SD. The Impact of DFT Functional, Cluster Model Size, and Implicit Solvation on the Structural Description of Single-Metal-Mediated DNA Phosphodiester Bond Cleavage: The Case Study of APE1. J Phys Chem B 2022; 126:10672-10683. [PMID: 36485014 DOI: 10.1021/acs.jpcb.2c06756] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phosphodiester bond hydrolysis in nucleic acids is a ubiquitous reaction that can be facilitated by enzymes called nucleases, which often use metal ions to achieve catalytic function. While a two-metal-mediated pathway has been well established for many enzymes, there is growing support that some enzymes require only one metal for the catalytic step. Using human apurinic/apyrimidinic endonuclease (APE1) as a prototypical example and cluster models, this study clarifies the impact of DFT functional, cluster model size, and implicit solvation on single-metal-mediated phosphodiester bond cleavage and provides insight into how to efficiently model this chemistry. Initially, a model containing 69 atoms built from a high-resolution X-ray crystal structure is used to explore the reaction pathway mapped by a range of DFT functionals and basis sets, which provides support for the use of standard functionals (M06-2X and B3LYP-D3) to study this reaction. Subsequently, systematically increasing the model size to 185 atoms by including additional amino acids and altering residue truncation points highlights that small models containing only a few amino acids or β carbon truncation points introduce model strains and lead to incorrect metal coordination. Indeed, a model that contains all key residues (general base and acid, residues that stabilize the substrate, and amino acids that maintain the metal coordination) is required for an accurate structural depiction of the one-metal-mediated phosphodiester bond hydrolysis by APE1, which results in 185 atoms. The additional inclusion of the broader enzyme environment through continuum solvation models has negligible effects. The insights gained in the present work can be used to direct future computational studies of other one-metal-dependent nucleases to provide a greater understanding of how nature achieves this difficult chemistry.
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Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Dylan J Nikkel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Mohamed M Aboelnga
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.,Chemistry Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
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7
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Tomasini M, Caporaso L, Trouvé J, Poater J, Gramage‐Doria R, Poater A. Unravelling Enzymatic Features in a Supramolecular Iridium Catalyst by Computational Calculations. Chemistry 2022; 28:e202201970. [PMID: 35788999 PMCID: PMC9804516 DOI: 10.1002/chem.202201970] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Indexed: 01/05/2023]
Abstract
Non-biological catalysts following the governing principles of enzymes are attractive systems to disclose unprecedented reactivities. Most of those existing catalysts feature an adaptable molecular recognition site for substrate binding that are prone to undergo conformational selection pathways. Herein, we present a non-biological catalyst that is able to bind substrates via the induced fit model according to in-depth computational calculations. The system, which is constituted by an inflexible substrate-recognition site derived from a zinc-porphyrin in the second coordination sphere, features destabilization of ground states as well as stabilization of transition states for the relevant iridium-catalyzed C-H bond borylation of pyridine. In addition, this catalyst appears to be most suited to tightly bind the transition state rather than the substrate. Besides these features, which are reminiscent of the action modes of enzymes, new elementary catalytic steps (i. e. C-B bond formation and catalyst regeneration) have been disclosed owing to the unique distortions encountered in the different intermediates and transition states.
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Affiliation(s)
- Michele Tomasini
- Institut de Química Computacional i CatàlisiDepartament de QuímicaUniversitat de Gironac/Mª Aurèlia Capmany 6917003GironaCataloniaSpain,Department of ChemistryUniversity of SalernoVia Ponte Don Melillo84084FiscianoItaly
| | - Lucia Caporaso
- Department of ChemistryUniversity of SalernoVia Ponte Don Melillo84084FiscianoItaly
| | | | - Jordi Poater
- Departament de Química Inorgànica i Orgànica & IQTCUBUniversitat de Barcelona08028BarcelonaSpain,ICREA08010BarcelonaSpain
| | | | - Albert Poater
- Institut de Química Computacional i CatàlisiDepartament de QuímicaUniversitat de Gironac/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
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8
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Prajapati S, Rabe von Pappenheim F, Tittmann K. Frontiers in the enzymology of thiamin diphosphate-dependent enzymes. Curr Opin Struct Biol 2022; 76:102441. [PMID: 35988322 DOI: 10.1016/j.sbi.2022.102441] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 07/07/2022] [Accepted: 07/11/2022] [Indexed: 11/25/2022]
Abstract
Enzymes that use thiamin diphosphate (ThDP), the biologically active derivative of vitamin B1, as a cofactor play important roles in cellular metabolism in all domains of life. The analysis of ThDP enzymes in the past decades have provided a general framework for our understanding of enzyme catalysis of this protein family. In this review, we will discuss recent advances in the field that include the observation of "unusual" reactions and reaction intermediates that highlight the chemical versatility of the thiamin cofactor. Further topics cover the structural basis of cooperativity of ThDP enzymes, novel insights into the mechanism and structure of selected enzymes, and the discovery of "superassemblies" as reported, for example, acetohydroxy acid synthase. Finally, we summarize recent findings in the structural organisation and mode of action of 2-keto acid dehydrogenase multienzyme complexes and discuss future directions of this exciting research field.
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Affiliation(s)
- Sabin Prajapati
- Department of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August University Göttingen, Julia-Lermontowa-Weg 3, D-37077 Göttingen, Germany; Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany.
| | - Fabian Rabe von Pappenheim
- Department of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August University Göttingen, Julia-Lermontowa-Weg 3, D-37077 Göttingen, Germany; Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany.
| | - Kai Tittmann
- Department of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August University Göttingen, Julia-Lermontowa-Weg 3, D-37077 Göttingen, Germany; Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany.
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9
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Prejanò M, Romeo I, La Serra MA, Russo N, Marino T. Computational Study Reveals the Role of Water Molecules in the Inhibition Mechanism of LAT1 by 1,2,3-Dithiazoles. J Chem Inf Model 2021; 61:5883-5892. [PMID: 34788052 PMCID: PMC8715508 DOI: 10.1021/acs.jcim.1c01012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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The L-type amino
acid transporter LAT1, involved in many biological
processes including the overexpression of some tumors, is considered
a potential pharmacological target. The 1,2,3-Dithiazole scaffold
was predicted to inhibit LAT1 by the formation of an intermolecular
disulfide bond with the thiolate group of cysteine(s). As a result
of the identification of these irreversible covalent inhibitors, we
decided to deeply investigate the recognition stage and the covalent
interaction, characterizing the chemical structures of the selected
ligands. With the aim to provide new insights into the access of the
ligands to the binding pocket and to reveal the residues involved
in the inhibition, we performed docking, molecular dynamics simulations,
and density functional theory-based investigation of three 1,2,3-dithiazoles
against LAT1. Our computational analysis further highlighted the crucial
role played by water molecules in the inhibition mechanism. The results
here presented are consistent with experimental observations and provide
insights that can be helpful for the rational design of new-to-come
LAT1’s inhibitors.
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Affiliation(s)
- Mario Prejanò
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy
| | - Isabella Romeo
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy
| | - Maria Antonietta La Serra
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy
| | - Nino Russo
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy
| | - Tiziana Marino
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy
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10
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Parise A, Romeo I, Russo N, Marino T. The Se-S Bond Formation in the Covalent Inhibition Mechanism of SARS-CoV-2 Main Protease by Ebselen-like Inhibitors: A Computational Study. Int J Mol Sci 2021; 22:9792. [PMID: 34575955 PMCID: PMC8467846 DOI: 10.3390/ijms22189792] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/03/2021] [Accepted: 09/07/2021] [Indexed: 12/20/2022] Open
Abstract
The inhibition mechanism of the main protease (Mpro) of SARS-CoV-2 by ebselen (EBS) and its analog with a hydroxyl group at position 2 of the benzisoselenazol-3(2H)-one ring (EBS-OH) was studied by using a density functional level of theory. Preliminary molecular dynamics simulations on the apo form of Mpro were performed taking into account both the hydrogen donor and acceptor natures of the Nδ and Nε of His41, a member of the catalytic dyad. The potential energy surfaces for the formation of the Se-S covalent bond mediated by EBS and EBS-OH on Mpro are discussed in detail. The EBS-OH shows a distinctive behavior with respect to EBS in the formation of the noncovalent complex. Due to the presence of canonical H-bonds and noncanonical ones involving less electronegative atoms, such as sulfur and selenium, the influence on the energy barriers and reaction energy of the Minnesota hybrid meta-GGA functionals M06, M06-2X and M08HX, and the more recent range-separated hybrid functional wB97X were also considered. The knowledge of the inhibition mechanism of Mpro by the small protease inhibitors EBS or EBS-OH can enlarge the possibilities for designing more potent and selective inhibitor-based drugs to be used in combination with other antiviral therapies.
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Affiliation(s)
- Angela Parise
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, CS, Italy; (A.P.); (I.R.); (N.R.)
- Institut de Chimie Physique UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Isabella Romeo
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, CS, Italy; (A.P.); (I.R.); (N.R.)
| | - Nino Russo
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, CS, Italy; (A.P.); (I.R.); (N.R.)
| | - Tiziana Marino
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, CS, Italy; (A.P.); (I.R.); (N.R.)
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11
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Nauton L, Hecquet L, Théry V. QM/MM Study of Human Transketolase: Thiamine Diphosphate Activation Mechanism and Complete Catalytic Cycle. J Chem Inf Model 2021; 61:3502-3515. [PMID: 34161071 DOI: 10.1021/acs.jcim.1c00190] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A computational model for human transketolase was proposed, showing that thiamine diphosphate activation was based on His110 in place of His481 reported in yeast transketolase. In addition, a complete catalytic reaction pathway was investigated using d-xylulose-5-phosphate and d-ribose-5-phosphate as substrates, showing at every step a perfect superimposition of our model with high-resolution crystallographic structures 3MOS, 4KXV, and 4KXX. This study shows that H2N4' of the active thiamine diphosphate "V form" no longer has a self-activating role but allows self-stabilization of the cofactor and of the Breslow intermediate. These advances in our knowledge of the human transketolase mechanism offer interesting prospects for the design of new drugs, this enzyme being involved in several diseases, and for a better understanding of the reactions catalyzed by transketolases from other sources.
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Affiliation(s)
- Lionel Nauton
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, F-63000 Clermont-Ferrand, France
| | - Laurence Hecquet
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, F-63000 Clermont-Ferrand, France
| | - Vincent Théry
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, F-63000 Clermont-Ferrand, France
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12
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Simari C, Prejanò M, Lufrano E, Sicilia E, Nicotera I. Exploring the Structure-Performance Relationship of Sulfonated Polysulfone Proton Exchange Membrane by a Combined Computational and Experimental Approach. Polymers (Basel) 2021; 13:959. [PMID: 33804763 PMCID: PMC8003876 DOI: 10.3390/polym13060959] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 01/01/2023] Open
Abstract
Sulfonated Polysulfone (sPSU) is emerging as a concrete alternative to Nafion ionomer for the development of proton exchange electrolytic membranes for low cost, environmentally friendly and high-performance PEM fuel cells. This ionomer has recently gained great consideration since it can effectively combine large availability on the market, excellent film-forming ability and remarkable thermo-mechanical resistance with interesting proton conductive properties. Despite the great potential, however, the morphological architecture of hydrated sPSU is still unknown. In this study, computational and experimental advanced tools are combined to preliminary describe the relationship between the microstructure of highly sulfonated sPSU (DS = 80%) and its physico-chemical, mechanical and electrochemical features. Computer simulations allowed for describing the architecture and to estimate the structural parameters of the sPSU membrane. Molecular dynamics revealed an interconnected lamellar-like structure for hydrated sPSU, with ionic clusters of about 14-18 Å in diameter corresponding to the hydrophilic sulfonic-acid-containing phase. Water dynamics were investigated by 1H Pulsed Field Gradient (PFG) NMR spectroscopy in a wide temperature range (20-120 °C) and the self-diffusion coefficients data were analyzed by a "two-sites" model. It allows to estimate the hydration number in excellent agreement with the theoretical simulation (e.g., about 8 mol H2O/mol SO3- @ 80 °C). The PEM performance was assessed in terms of dimensional, thermo-mechanical and electrochemical properties by swelling tests, DMA and EIS, respectively. The peculiar microstructure of sPSU provides a wider thermo-mechanical stability in comparison to Nafion, but lower dimensional and conductive features. Nonetheless, the single H2/O2 fuel cell assembled with sPSU exhibited better features than any earlier published hydrocarbon ionomers, thus opening interesting perspectives toward the design and preparation of high-performing sPSU-based PEMs.
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Affiliation(s)
- Cataldo Simari
- Department of Chemistry and Chemical Technologies—CTC, University of Calabria, Via Pietro Bucci, 87036 Rende, Italy; (E.L.); (E.S.); (I.N.)
| | - Mario Prejanò
- Department of Chemistry and Chemical Technologies—CTC, University of Calabria, Via Pietro Bucci, 87036 Rende, Italy; (E.L.); (E.S.); (I.N.)
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Medina FE, Prejanò M. Water Molecules Allow the Intramolecular Activation of the Thiamine Di-Phosphate Cofactor in Human Transketolase: Mechanistic Insights into a Famous Proposal. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05414] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Fabiola E. Medina
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Autopista Concepción-Talcahuano, Talcahuano 7100, Chile
| | - Mario Prejanò
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-10691, Sweden
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Banerjee S. An insight into the interaction between α-ketoamide- based inhibitor and coronavirus main protease: A detailed in silico study. Biophys Chem 2021; 269:106510. [PMID: 33285430 PMCID: PMC7695570 DOI: 10.1016/j.bpc.2020.106510] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
The search for therapeutic drugs that can neutralize the effects of COVID-2019 (SARS-CoV-2) infection is the main focus of current research. The coronavirus main protease (Mpro) is an attractive target for anti-coronavirus drug design. Further, α-ketoamide is proved to be very effective as a reversible covalent-inhibitor against cysteine proteases. Herein, we report on the non-covalent to the covalent adduct formation mechanism of α-ketoamide-based inhibitor with the enzyme active site amino acids by QM/SQM model (QM = quantum mechanical, SQM = semi-empirical QM). To uncover the mechanism, we focused on two approaches: a concerted and a stepwise fashion. The concerted pathway proceeds via deprotonation of the thiol of cysteine (here, Cys145 SγH) and simultaneous reversible nucleophilic attack of sulfur onto the α-ketoamide warhead. In this work, we propose three plausible concerted pathways. On the contrary, in a traditional two-stage pathway, the first step is proton transfer from Cys145 SγH to His41 Nδ forming an ion pair, and consecutively, in the second step, the thiolate ion attacks the α-keto group to form a thiohemiketal. In this reaction, we find that the stability of the tetrahedral intermediate oxyanion/hydroxyl group plays an important role. Moreover, as the α-keto group has two faces Si or Re for the nucleophilic attack, we considered both possibilities of attack leading to S- and R-thiohemiketal. We computed the structural, electronic, and energetic parameters of all stationary points including transition states via ONIOM and pure DFT method. Additionally, to characterize covalent, weak noncovalent interaction (NCI) and hydrogen-bonds, we applied NCI-reduced density gradient (NCI-RDG) methods along with Bader's Quantum Theory of Atoms-in-Molecules (QTAIM) and natural bonding orbital (NBO) analysis.
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Affiliation(s)
- Snehasis Banerjee
- Department of Chemistry, Government College of Engineering and Leather Technology, Salt Lake, Sector-3, Kolkata, PIN-700106, West Bengal, India.
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Prejanò M, Romeo I, Russo N, Marino T. On the Catalytic Activity of the Engineered Coiled-Coil Heptamer Mimicking the Hydrolase Enzymes: Insights from a Computational Study. Int J Mol Sci 2020; 21:E4551. [PMID: 32604744 PMCID: PMC7352413 DOI: 10.3390/ijms21124551] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 01/22/2023] Open
Abstract
Recently major advances were gained on the designed proteins aimed to generate biomolecular mimics of proteases. Although such enzyme-like catalysts must still suffer refinements for improving the catalytic activity, at the moment, they represent a good example of artificial enzymes to be tested in different fields. Herein, a de novo designed homo-heptameric peptide assembly (CC-Hept) where the esterase activity towards p-nitro-phenylacetate was obtained for introduction of the catalytic triad (Cys-His-Glu) into the hydrophobic matrix, is the object of the present combined molecular dynamics and quantum mechanics/molecular mechanics investigation. Constant pH Molecular Dynamics simulations on the apoform of CC-Hept suggested that the Cys residues are present in the protonated form. Molecular dynamics (MD) simulations of the enzyme-substrate complex evidenced the attitude of the enzyme-like system to retain water molecules, necessary in the hydrolytic reaction, in correspondence of the active site, represented by the Cys-His-Glu triad on each of the seven chains, without significant structural perturbations. A detailed reaction mechanism of esterase activity of CC-Hept-Cys-His-Glu was investigated on the basis of the quantum mechanics/molecular mechanics calculations employing a large quantum mechanical (QM) region of the active site. The proposed mechanism is consistent with available esterases kinetics and structural data. The roles of the active site residues were also evaluated. The deacylation phase emerged as the rate-determining step, in agreement with esterase activity of other natural proteases.
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Affiliation(s)
| | | | - Nino Russo
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy; (M.P.); (I.R.)
| | - Tiziana Marino
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy; (M.P.); (I.R.)
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