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Mittal S, Nisler C, Szostak JW. Simulations predict preferred Mg 2+ coordination in a nonenzymatic primer-extension reaction center. Biophys J 2024; 123:1579-1591. [PMID: 38702884 PMCID: PMC11214020 DOI: 10.1016/j.bpj.2024.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/24/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024] Open
Abstract
The mechanism by which genetic information was copied prior to the evolution of ribozymes is of great interest because of its importance to the origin of life. The most effective known process for the nonenzymatic copying of an RNA template is primer extension by a two-step pathway in which 2-aminoimidazole-activated nucleotides first react with each other to form an imidazolium-bridged intermediate that subsequently reacts with the primer. Reaction kinetics, structure-activity relationships, and X-ray crystallography have provided insight into the overall reaction mechanism, but many puzzles remain. In particular, high concentrations of Mg2+ are required for efficient primer extension, but the mechanism by which Mg2+ accelerates primer extension remains unknown. By analogy with the mechanism of DNA and RNA polymerases, a role for Mg2+ in facilitating the deprotonation of the primer 3'-hydroxyl is often assumed, but no catalytic metal ion is seen in crystal structures of the primer-extension complex. To explore the potential effects of Mg2+ binding in the reaction center, we performed atomistic molecular dynamics simulations of a series of modeled complexes in which a Mg2+ ion was placed in the reaction center with inner-sphere coordination with different sets of functional groups. Our simulations suggest that coordination of a Mg2+ ion with both O3' of the terminal primer nucleotide and the pro-Sp nonbridging oxygen of the reactive phosphate of an imidazolium-bridged dinucleotide would help to pre-organize the structure of the primer/template substrate complex to favor the primer-extension reaction. Our results suggest that the catalytic metal ion may play an important role in overcoming electrostatic repulsion between a deprotonated O3' and the reactive phosphate of the bridged dinucleotide and lead to testable predictions of the mode of Mg2+ binding that is most relevant to catalysis of primer extension.
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Affiliation(s)
- Shriyaa Mittal
- Howard Hughes Medical Institute, Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts; Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Collin Nisler
- Howard Hughes Medical Institute, Department of Chemistry, University of Chicago, Chicago, Illinois
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts; Department of Genetics, Harvard Medical School, Boston, Massachusetts; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts; Howard Hughes Medical Institute, Department of Chemistry, University of Chicago, Chicago, Illinois.
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2
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Ciardullo G, Parise A, Prejanò M, Marino T. Viral RNA Replication Suppression of SARS-CoV-2: Atomistic Insights into Inhibition Mechanisms of RdRp Machinery by ddhCTP. J Chem Inf Model 2024; 64:1593-1604. [PMID: 38412057 DOI: 10.1021/acs.jcim.3c01919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
The nonstructural protein 12, known as RNA-dependent RNA polymerase (RdRp), is essential for both replication and repair of the viral genome. The RdRp of SARS-CoV-2 has been used as a promising candidate for drug development since the inception of the COVID-19 spread. In this work, we performed an in silico investigation on the insertion of the naturally modified pyrimidine nucleobase ddhCTP into the SARS-CoV-2 RdRp active site, in a comparative analysis with the natural one (CTP). The modification in ddhCTP involves the removal of the 3'-hydroxyl group that prevents the addition of subsequent nucleotides into the nascent strand, acting as an RNA chain terminator inhibitor. Quantum mechanical investigations helped to shed light on the mechanistic source of RdRp activity on the selected nucleobases, and comprehensive all-atom simulations provided insights about the structural rearrangements occurring in the active-site region when inorganic pyrophosphate (PPi) is formed. Subsequently, the intricate pathways for the release of PPi, the catalytic product of RdRp, were investigated using Umbrella Sampling simulations. The results are in line with the available experimental data and contribute to a more comprehensive point of view on such an important viral enzyme.
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Affiliation(s)
- Giada Ciardullo
- Dipartimento di Chimica E Tecnologie Chimiche, Laboratorio PROMOCS Cubo 14C, Università della Calabria, RENDE (CS) I-87036, Italy
| | - Angela Parise
- Consiglio Nazionale Delle Ricerche (CNR)-IOM C/O International School for Advanced Studies (SISSA/ISAS), Via Bonomea 265, Trieste 34136, Italy
| | - Mario Prejanò
- Dipartimento di Chimica E Tecnologie Chimiche, Laboratorio PROMOCS Cubo 14C, Università della Calabria, RENDE (CS) I-87036, Italy
| | - Tiziana Marino
- Dipartimento di Chimica E Tecnologie Chimiche, Laboratorio PROMOCS Cubo 14C, Università della Calabria, RENDE (CS) I-87036, Italy
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Kaur R, Wetmore SD. Is Metal Stabilization of the Leaving Group Required or Can Lysine Facilitate Phosphodiester Bond Cleavage in Nucleic Acids? A Computational Study of EndoV. J Chem Inf Model 2024; 64:944-959. [PMID: 38253321 DOI: 10.1021/acs.jcim.3c01775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Endonuclease V (EndoV) is a single-metal-dependent enzyme that repairs deaminated DNA nucleobases in cells by cleaving the phosphodiester bond, and this enzyme has proven to be a powerful tool in biotechnology and medicine. The catalytic mechanism used by EndoV must be understood to design new disease detection and therapeutic solutions and further exploit the enzyme in interdisciplinary applications. This study has used a mixed molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) approach to compare eight distinct catalytic pathways and provides the first proposed mechanism for bacterial EndoV. The calculations demonstrate that mechanisms involving either direct or indirect metal coordination to the leaving group of the substrate previously proposed for other nucleases are unlikely for EndoV, regardless of the general base (histidine, aspartate, and substrate phosphate moiety). Instead, distinct catalytic pathways are characterized for EndoV that involve K139 stabilizing the leaving group, a metal-coordinated water stabilizing the transition structure, and either H214 or a substrate phosphate group activating the water nucleophile. In silico K139A and H214A mutational results support the newly proposed roles of these residues. Although this is a previously unseen combination of general base, general acid, and metal-binding architecture for a one-metal-dependent endonuclease, our proposed catalytic mechanisms are fully consistent with experimental kinetic, structural, and mutational data. In addition to substantiating a growing body of literature, suggesting that one metal is enough to catalyze P-O bond cleavage in nucleic acids, this new fundamental understanding of the catalytic function will promote the exploration of new and improved applications of EndoV.
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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
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
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Wang X, Xu T, Yao Y, Cheung PPH, Gao X, Zhang L. SARS-CoV-2 RNA-Dependent RNA Polymerase Follows Asynchronous Translocation Pathway for Viral Transcription and Replication. J Phys Chem Lett 2023; 14:10119-10128. [PMID: 37922192 DOI: 10.1021/acs.jpclett.3c01249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2023]
Abstract
Translocation is one essential step for the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) to exert viral replication and transcription. Although cryo-EM structures of SARS-CoV-2 RdRp are available, the molecular mechanisms of dynamic translocation remain elusive. Herein, we constructed a Markov state model based on extensive molecular dynamics simulations to elucidate the translocation dynamics of the SARS-CoV-2 RdRp. We identified two intermediates that pinpoint the rate-limiting step of translocation and characterize the asynchronous movement of the template-primer duplex. The 3'-terminal nucleotide in the primer strand lags behind due to the uneven distribution of protein-RNA interactions, while the translocation of the template strand is delayed by the hurdle residue K500. Even so, the two strands share the same "ratchet" to stabilize the polymerase in the post-translocation state, suggesting a Brownian-ratchet model. Overall, our study provides intriguing insights into SARS-CoV-2 replication and transcription, which would open a new avenue for drug discoveries.
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Affiliation(s)
- Xiaowei Wang
- Department of Chemical and Biological Engineering and Department of Mathematics, Hong Kong University of Science and Technology Kowloon, Clear Water Bay, Hong Kong
| | - Tiantian Xu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Yao
- Department of Chemical and Biological Engineering and Department of Mathematics, Hong Kong University of Science and Technology Kowloon, Clear Water Bay, Hong Kong
| | - Peter Pak-Hang Cheung
- Li Ka Shing Institute of Health Sciences, Department of Chemical Pathology, Chinese University of Hong Kong, 999077, Hong Kong
| | - Xin Gao
- Computational Bioscience Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
- Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Fuzhou, Fujian 361005, China
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D'Anna L, Miclot T, Bignon E, Perricone U, Barone G, Monari A, Terenzi A. Resolving a guanine-quadruplex structure in the SARS-CoV-2 genome through circular dichroism and multiscale molecular modeling. Chem Sci 2023; 14:11332-11339. [PMID: 37886086 PMCID: PMC10599604 DOI: 10.1039/d3sc04004f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/08/2023] [Indexed: 10/28/2023] Open
Abstract
The genome of SARS-CoV-2 coronavirus is made up of a single-stranded RNA fragment that can assume a specific secondary structure, whose stability can influence the virus's ability to reproduce. Recent studies have identified putative guanine quadruplex sequences in SARS-CoV-2 genome fragments that are involved in coding for both structural and non-structural proteins. In this contribution, we focus on a specific G-rich sequence referred to as RG-2, which codes for the non-structural protein 10 (Nsp10) and assumes a guanine-quadruplex (G4) arrangement. We provide the secondary structure of RG-2 G4 at atomistic resolution by molecular modeling and simulation, validated by the superposition of experimental and calculated electronic circular dichroism spectra. Through both experimental and simulation approaches, we have demonstrated that pyridostatin (PDS), a widely recognized G4 binder, can bind to and stabilize RG-2 G4 more strongly than RG-1, another G4 forming sequence that was previously proposed as a potential target for antiviral drug candidates. Overall, this study highlights RG-2 as a valuable target to inhibit the translation and replication of SARS-CoV-2, paving the way towards original therapeutic approaches against emerging RNA viruses.
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Affiliation(s)
- Luisa D'Anna
- Department of Biological, Chemical and Pharmaceutical Sciences, University of Palermo Viale delle Scienze, Ed. 17 90128 Palermo Italy
| | - Tom Miclot
- Department of Biological, Chemical and Pharmaceutical Sciences, University of Palermo Viale delle Scienze, Ed. 17 90128 Palermo Italy
- Université de Lorraine and CNRS UMR 7019 LPCT F-54000 Nancy France
| | | | - Ugo Perricone
- Fondazione Ri.MED Via Filippo Marini 14 90128 Palermo Italy
| | - Giampaolo Barone
- Department of Biological, Chemical and Pharmaceutical Sciences, University of Palermo Viale delle Scienze, Ed. 17 90128 Palermo Italy
| | - Antonio Monari
- Université Paris Cité and CNRS, ITODYS F-75006 Paris France
| | - Alessio Terenzi
- Department of Biological, Chemical and Pharmaceutical Sciences, University of Palermo Viale delle Scienze, Ed. 17 90128 Palermo Italy
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Bignon E, Grandemange S, Dumont E, Monari A. How SARS-CoV-2 Alters the Regulation of Gene Expression in Infected Cells. J Phys Chem Lett 2023; 14:3199-3207. [PMID: 36971439 PMCID: PMC10068877 DOI: 10.1021/acs.jpclett.3c00582] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 03/23/2023] [Indexed: 06/18/2023]
Abstract
Nonstructural accessory proteins in viruses play a key role in hijacking the basic cellular mechanisms, which is essential to promote the virus survival and evasion of the immune system. The immonuglobulin-like open reading frame 8 (ORF8) protein expressed by SARS-CoV-2 accumulates in the nucleus and may influence the regulation of the gene expression in infected cells. In this contribution, by using microsecond time-scale all-atom molecular dynamics simulations, we unravel the structural bases behind the epigenetic action of ORF8. In particular, we highlight how the protein is able to form stable aggregates with DNA through a histone tail-like motif, and how this interaction is influenced by post-translational modifications, such as acetylation and methylation, which are known epigenetic markers in histones. Our work not only clarifies the molecular mechanisms behind the perturbation of the epigenetic regulation caused by the viral infection but also offers an unusual perspective which may foster the development of original antivirals.
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Affiliation(s)
- Emmanuelle Bignon
- Université
de Lorraine and CNRS, UMR 7019 LPCT, F-54000 Nancy, France
| | | | - Elise Dumont
- Université
Côte d’Azur, Institut de Chimie de Nice, UMR 7272, Parc Valrose, 28 avenue Valrose, F-06108 Nice, France
- Institut
Universitaire de France, 5 rue Descartes, F-75005 Paris, France
| | - Antonio Monari
- Université
Paris Cité and CNRS, ITODYS, F-75006 Paris, France
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Parise A, Ciardullo G, Prejanò M, Lande ADL, Marino T. On the Recognition of Natural Substrate CTP and Endogenous Inhibitor ddhCTP of SARS-CoV-2 RNA-Dependent RNA Polymerase: A Molecular Dynamics Study. J Chem Inf Model 2022; 62:4916-4927. [PMID: 36219674 DOI: 10.1021/acs.jcim.2c01002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The novel coronavirus SARS-CoV-2 is the causative agent of the COVID-19 outbreak that is affecting the entire planet. As the pandemic is still spreading worldwide, with multiple mutations of the virus, it is of interest and of help to employ computational methods for identifying potential inhibitors of the enzymes responsible for viral replication. Attractive antiviral nucleotide analogue RNA-dependent RNA polymerase (RdRp) chain terminator inhibitors are investigated with this purpose. This study, based on molecular dynamics (MD) simulations, addresses the important aspects of the incorporation of an endogenously synthesized nucleoside triphosphate, ddhCTP, in comparison with the natural nucleobase cytidine triphosphate (CTP) in RdRp. The ddhCTP species is the product of the viperin antiviral protein as part of the innate immune response. The absence of the ribose 3'-OH in ddhCTP could have important implications in its inhibitory mechanism of RdRp. We built an in silico model of the RNA strand embedded in RdRp using experimental methods, starting from the cryo-electron microscopy structure and exploiting the information obtained by spectrometry on the RNA sequence. We determined that the model was stable during the MD simulation time. The obtained results provide deeper insights into the incorporation of nucleoside triphosphates, whose molecular mechanism by the RdRp active site still remains elusive.
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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.,Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, Orsay 91405, France
| | - Giada Ciardullo
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, CS, Italy
| | - Mario Prejanò
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, CS, Italy
| | - Aurélien de la Lande
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, Orsay 91405, France
| | - Tiziana Marino
- Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, CS, Italy
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