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1.
Nucleic Acids Res ; 50(2): 635-650, 2022 01 25.
Article in English | MEDLINE | ID: covidwho-1621653

ABSTRACT

Coronaviral methyltransferases (MTases), nsp10/16 and nsp14, catalyze the last two steps of viral RNA-cap creation that takes place in cytoplasm. This cap is essential for the stability of viral RNA and, most importantly, for the evasion of innate immune system. Non-capped RNA is recognized by innate immunity which leads to its degradation and the activation of antiviral immunity. As a result, both coronaviral MTases are in the center of scientific scrutiny. Recently, X-ray and cryo-EM structures of both enzymes were solved even in complex with other parts of the viral replication complex. High-throughput screening as well as structure-guided inhibitor design have led to the discovery of their potent inhibitors. Here, we critically summarize the tremendous advancement of the coronaviral MTase field since the beginning of COVID pandemic.


Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Coronavirus/drug effects , Coronavirus/enzymology , Methyltransferases/antagonists & inhibitors , Methyltransferases/chemistry , Methyltransferases/metabolism , Amino Acid Sequence , Amino Acids/chemistry , Binding Sites , Coronavirus/genetics , Drug Discovery , Humans , Methylation , Models, Molecular , Molecular Conformation , Molecular Structure , Protein Binding , RNA, Viral/chemistry , RNA, Viral/genetics , RNA, Viral/metabolism , Structure-Activity Relationship
2.
Antiviral Res ; 197: 105232, 2022 01.
Article in English | MEDLINE | ID: covidwho-1588314

ABSTRACT

We report the in vitro antiviral activity of DZNep (3-Deazaneplanocin A; an inhibitor of S-adenosylmethionine-dependent methyltransferase) against SARS-CoV-2, besides demonstrating its protective efficacy against lethal infection of infectious bronchitis virus (IBV, a member of the Coronaviridae family). DZNep treatment resulted in reduced synthesis of SARS-CoV-2 RNA and proteins without affecting other steps of viral life cycle. We demonstrated that deposition of N6-methyl adenosine (m6A) in SARS-CoV-2 RNA in the infected cells recruits heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), an RNA binding protein which serves as a m6A reader. DZNep inhibited the recruitment of hnRNPA1 at m6A-modified SARS-CoV-2 RNA which eventually suppressed the synthesis of the viral genome. In addition, m6A-marked RNA and hnRNPA1 interaction was also shown to regulate early translation to replication switch of SARS-CoV-2 genome. Furthermore, abrogation of methylation by DZNep also resulted in defective synthesis of the 5' cap of viral RNA, thereby resulting in its failure to interact with eIF4E (a cap-binding protein), eventually leading to a decreased synthesis of viral proteins. Most importantly, DZNep-resistant mutants could not be observed upon long-term sequential passage of SARS-CoV-2 in cell culture. In summary, we report the novel role of methylation in the life cycle of SARS-CoV-2 and propose that targeting the methylome using DZNep could be of significant therapeutic value against SARS-CoV-2 infection.


Subject(s)
Adenosine/analogs & derivatives , Genome, Viral/drug effects , Methyltransferases/antagonists & inhibitors , SARS-CoV-2/drug effects , Adenosine/pharmacology , Animals , Chick Embryo , Chlorocebus aethiops , Chromatin Immunoprecipitation Sequencing , DNA Methylation/drug effects , DNA Methylation/physiology , Drug Resistance, Viral/drug effects , Genome, Viral/genetics , Heterogeneous Nuclear Ribonucleoprotein A1/metabolism , Humans , Lethal Dose 50 , Mice , Protein Biosynthesis/drug effects , RNA, Viral/drug effects , RNA, Viral/metabolism , Rabbits , SARS-CoV-2/genetics , Specific Pathogen-Free Organisms , Transcription, Genetic/drug effects , Vero Cells
3.
Nat Commun ; 12(1): 4848, 2021 08 11.
Article in English | MEDLINE | ID: covidwho-1354102

ABSTRACT

There is currently a lack of effective drugs to treat people infected with SARS-CoV-2, the cause of the global COVID-19 pandemic. The SARS-CoV-2 Non-structural protein 13 (NSP13) has been identified as a target for anti-virals due to its high sequence conservation and essential role in viral replication. Structural analysis reveals two "druggable" pockets on NSP13 that are among the most conserved sites in the entire SARS-CoV-2 proteome. Here we present crystal structures of SARS-CoV-2 NSP13 solved in the APO form and in the presence of both phosphate and a non-hydrolysable ATP analog. Comparisons of these structures reveal details of conformational changes that provide insights into the helicase mechanism and possible modes of inhibition. To identify starting points for drug development we have performed a crystallographic fragment screen against NSP13. The screen reveals 65 fragment hits across 52 datasets opening the way to structure guided development of novel antiviral agents.


Subject(s)
Methyltransferases/chemistry , RNA Helicases/chemistry , SARS-CoV-2/chemistry , Viral Nonstructural Proteins/chemistry , Adenosine Triphosphate/chemistry , Adenosine Triphosphate/metabolism , Amino Acid Sequence , Apoenzymes/chemistry , Apoenzymes/metabolism , Binding Sites , Crystallography, X-Ray , Drug Design , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/metabolism , Methyltransferases/antagonists & inhibitors , Methyltransferases/metabolism , Models, Molecular , Phosphates/chemistry , Phosphates/metabolism , Protein Conformation , RNA Helicases/antagonists & inhibitors , RNA Helicases/metabolism , RNA, Viral/chemistry , RNA, Viral/metabolism , SARS-CoV-2/enzymology , Structure-Activity Relationship , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism
4.
Genes Dev ; 35(13-14): 1005-1019, 2021 07 01.
Article in English | MEDLINE | ID: covidwho-1334329

ABSTRACT

N6-methyladenosine (m6A) is an abundant internal RNA modification, influencing transcript fate and function in uninfected and virus-infected cells. Installation of m6A by the nuclear RNA methyltransferase METTL3 occurs cotranscriptionally; however, the genomes of some cytoplasmic RNA viruses are also m6A-modified. How the cellular m6A modification machinery impacts coronavirus replication, which occurs exclusively in the cytoplasm, is unknown. Here we show that replication of SARS-CoV-2, the agent responsible for the COVID-19 pandemic, and a seasonal human ß-coronavirus HCoV-OC43, can be suppressed by depletion of METTL3 or cytoplasmic m6A reader proteins YTHDF1 and YTHDF3 and by a highly specific small molecule METTL3 inhibitor. Reduction of infectious titer correlates with decreased synthesis of viral RNAs and the essential nucleocapsid (N) protein. Sites of m6A modification on genomic and subgenomic RNAs of both viruses were mapped by methylated RNA immunoprecipitation sequencing (meRIP-seq). Levels of host factors involved in m6A installation, removal, and recognition were unchanged by HCoV-OC43 infection; however, nuclear localization of METTL3 and cytoplasmic m6A readers YTHDF1 and YTHDF2 increased. This establishes that coronavirus RNAs are m6A-modified and host m6A pathway components control ß-coronavirus replication. Moreover, it illustrates the therapeutic potential of targeting the m6A pathway to restrict coronavirus reproduction.


Subject(s)
Coronavirus OC43, Human/physiology , RNA Processing, Post-Transcriptional/genetics , SARS-CoV-2/physiology , Virus Replication/genetics , Adenosine/analogs & derivatives , Adenosine/genetics , Adenosine/metabolism , Cell Line , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Gene Expression Regulation/drug effects , Host-Pathogen Interactions/drug effects , Humans , Methyltransferases/antagonists & inhibitors , Methyltransferases/metabolism , Nucleocapsid Proteins , RNA, Viral/metabolism , RNA-Binding Proteins/metabolism , Virus Replication/drug effects
5.
Antiviral Res ; 193: 105142, 2021 09.
Article in English | MEDLINE | ID: covidwho-1321985

ABSTRACT

SARS-CoV-2, the cause of the currently ongoing COVID-19 pandemic, encodes its own mRNA capping machinery. Insights into this capping system may provide new ideas for therapeutic interventions and drug discovery. In this work, we employ a previously developed Py-FLINT screening approach to study the inhibitory effects of compounds against the cap guanine N7-methyltransferase enzyme, which is involved in SARS-CoV-2 mRNA capping. We screened five commercially available libraries (7039 compounds in total) to identify 83 inhibitors with IC50 < 50 µM, which were further validated using RP HPLC and dot blot assays. Novel fluorescence anisotropy binding assays were developed to examine the targeted binding site. The inhibitor structures were analyzed for structure-activity relationships in order to define common structural patterns. Finally, the most potent inhibitors were tested for antiviral activity on SARS-CoV-2 in a cell based assay.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Methyltransferases/antagonists & inhibitors , Nucleotidyltransferases/antagonists & inhibitors , SARS-CoV-2/drug effects , Antiviral Agents/chemistry , COVID-19/virology , Cell Line , Exoribonucleases/antagonists & inhibitors , Exoribonucleases/metabolism , High-Throughput Screening Assays , Humans , Inhibitory Concentration 50 , Methyltransferases/metabolism , Nucleotidyltransferases/metabolism , RNA Caps , RNA, Viral/genetics , RNA, Viral/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects
6.
Biochem J ; 478(13): 2481-2497, 2021 07 16.
Article in English | MEDLINE | ID: covidwho-1289949

ABSTRACT

The COVID-19 pandemic has presented itself as one of the most critical public health challenges of the century, with SARS-CoV-2 being the third member of the Coronaviridae family to cause a fatal disease in humans. There is currently only one antiviral compound, remdesivir, that can be used for the treatment of COVID-19. To identify additional potential therapeutics, we investigated the enzymatic proteins encoded in the SARS-CoV-2 genome. In this study, we focussed on the viral RNA cap methyltransferases, which play key roles in enabling viral protein translation and facilitating viral escape from the immune system. We expressed and purified both the guanine-N7 methyltransferase nsp14, and the nsp16 2'-O-methyltransferase with its activating cofactor, nsp10. We performed an in vitro high-throughput screen for inhibitors of nsp14 using a custom compound library of over 5000 pharmaceutical compounds that have previously been characterised in either clinical or basic research. We identified four compounds as potential inhibitors of nsp14, all of which also showed antiviral capacity in a cell-based model of SARS-CoV-2 infection. Three of the four compounds also exhibited synergistic effects on viral replication with remdesivir.


Subject(s)
Antiviral Agents/pharmacology , Drug Evaluation, Preclinical , Exoribonucleases/antagonists & inhibitors , Methyltransferases/antagonists & inhibitors , RNA Caps/metabolism , SARS-CoV-2/enzymology , Small Molecule Libraries/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Alanine/analogs & derivatives , Alanine/pharmacology , Animals , Antiviral Agents/chemistry , Chlorobenzenes/pharmacology , Chlorocebus aethiops , Enzyme Assays , Exoribonucleases/genetics , Exoribonucleases/isolation & purification , Exoribonucleases/metabolism , Fluorescence Resonance Energy Transfer , High-Throughput Screening Assays , Indazoles/pharmacology , Indenes/pharmacology , Indoles/pharmacology , Methyltransferases/genetics , Methyltransferases/isolation & purification , Methyltransferases/metabolism , Nitriles/pharmacology , Phenothiazines/pharmacology , Purines/pharmacology , Reproducibility of Results , SARS-CoV-2/drug effects , Small Molecule Libraries/chemistry , Substrate Specificity , Trifluperidol/pharmacology , Vero Cells , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/isolation & purification , Viral Nonstructural Proteins/metabolism , Viral Regulatory and Accessory Proteins/genetics , Viral Regulatory and Accessory Proteins/isolation & purification , Viral Regulatory and Accessory Proteins/metabolism
7.
Molecules ; 26(5)2021 Mar 07.
Article in English | MEDLINE | ID: covidwho-1136523

ABSTRACT

With the emergence and global spread of the COVID-19 pandemic, the scientific community worldwide has focused on search for new therapeutic strategies against this disease. One such critical approach is targeting proteins such as helicases that regulate most of the SARS-CoV-2 RNA metabolism. The purpose of the current study was to predict a library of phytochemicals derived from diverse plant families with high binding affinity to SARS-CoV-2 helicase (Nsp13) enzyme. High throughput virtual screening of the Medicinal Plant Database for Drug Design (MPD3) database was performed on SARS-CoV-2 helicase using AutoDock Vina. Nilotinib, with a docking value of -9.6 kcal/mol, was chosen as a reference molecule. A compound (PubChem CID: 110143421, ZINC database ID: ZINC257223845, eMolecules: 43290531) was screened as the best binder (binding energy of -10.2 kcal/mol on average) to the enzyme by using repeated docking runs in the screening process. On inspection, the compound was disclosed to show different binding sites of the triangular pockets collectively formed by Rec1A, Rec2A, and 1B domains and a stalk domain at the base. The molecule is often bound to the ATP binding site (referred to as binding site 2) of the helicase enzyme. The compound was further discovered to fulfill drug-likeness and lead-likeness criteria, have good physicochemical and pharmacokinetics properties, and to be non-toxic. Molecular dynamic simulation analysis of the control/lead compound complexes demonstrated the formation of stable complexes with good intermolecular binding affinity. Lastly, affirmation of the docking simulation studies was accomplished by estimating the binding free energy by MMPB/GBSA technique. Taken together, these findings present further in silco investigation of plant-derived lead compounds to effectively address COVID-19.


Subject(s)
Methyltransferases/antagonists & inhibitors , Methyltransferases/metabolism , RNA Helicases/antagonists & inhibitors , RNA Helicases/metabolism , SARS-CoV-2/enzymology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/pharmacokinetics , Antiviral Agents/toxicity , Binding Sites , Biological Availability , COVID-19/drug therapy , Computational Biology/methods , Databases, Chemical , Drug Design , Humans , Hydrogen Bonding , Methyltransferases/chemistry , Molecular Docking Simulation , Molecular Dynamics Simulation , Phytochemicals/chemistry , Phytochemicals/metabolism , Plants, Medicinal/chemistry , Protein Binding , Protein Domains/drug effects , Pyrimidines/chemistry , Pyrimidines/metabolism , Pyrimidines/pharmacokinetics , Pyrimidines/toxicity , RNA Helicases/chemistry , Structure-Activity Relationship , Thermodynamics , Viral Nonstructural Proteins/chemistry
8.
PLoS One ; 16(2): e0246181, 2021.
Article in English | MEDLINE | ID: covidwho-1088753

ABSTRACT

The 2019 emergence of, SARS-CoV-2 has tragically taken an immense toll on human life and far reaching impacts on society. There is a need to identify effective antivirals with diverse mechanisms of action in order to accelerate preclinical development. This study focused on five of the most established drug target proteins for direct acting small molecule antivirals: Nsp5 Main Protease, Nsp12 RNA-dependent RNA polymerase, Nsp13 Helicase, Nsp16 2'-O methyltransferase and the S2 subunit of the Spike protein. A workflow of solvent mapping and free energy calculations was used to identify and characterize favorable small-molecule binding sites for an aromatic pharmacophore (benzene). After identifying the most favorable sites, calculated ligand efficiencies were compared utilizing computational fragment screening. The most favorable sites overall were located on Nsp12 and Nsp16, whereas the most favorable sites for Nsp13 and S2 Spike had comparatively lower ligand efficiencies relative to Nsp12 and Nsp16. Utilizing fragment screening on numerous possible sites on Nsp13 helicase, we identified a favorable allosteric site on the N-terminal zinc binding domain (ZBD) that may be amenable to virtual or biophysical fragment screening efforts. Recent structural studies of the Nsp12:Nsp13 replication-transcription complex experimentally corroborates ligand binding at this site, which is revealed to be a functional Nsp8:Nsp13 protein-protein interaction site in the complex. Detailed structural analysis of Nsp13 ZBD conformations show the role of induced-fit flexibility in this ligand binding site and identify which conformational states are associated with efficient ligand binding. We hope that this map of over 200 possible small-molecule binding sites for these drug targets may be of use for ongoing discovery, design, and drug repurposing efforts. This information may be used to prioritize screening efforts or aid in the process of deciphering how a screening hit may bind to a specific target protein.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/virology , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Methyltransferases/metabolism , RNA Helicases/metabolism , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/metabolism , Allosteric Site , Binding Sites , COVID-19/drug therapy , COVID-19/metabolism , Computational Biology/methods , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/metabolism , Coronavirus RNA-Dependent RNA Polymerase/antagonists & inhibitors , Coronavirus RNA-Dependent RNA Polymerase/chemistry , Humans , Methyltransferases/antagonists & inhibitors , Methyltransferases/chemistry , Models, Molecular , Molecular Targeted Therapy , Protein Binding , RNA Helicases/antagonists & inhibitors , RNA Helicases/chemistry , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2/metabolism , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry , Virus Replication/drug effects
9.
Expert Opin Ther Pat ; 31(4): 339-350, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1087605

ABSTRACT

Introduction: Coronaviruses encode a helicase that is essential for viral replication and represents an excellent antiviral target. However, only a few coronavirus helicase inhibitors have been patented. These patents include drug-like compound SSYA10-001, aryl diketo acids (ADK), and dihydroxychromones. Additionally, adamantane-derived bananins, natural flavonoids, one acrylamide derivative [(E)-3-(furan-2-yl)-N-(4-sulfamoylphenyl)acrylamide], a purine derivative (7-ethyl-8-mercapto-3-methyl-3,7-dihydro-1 H-purine-2,6-dione), and a few bismuth complexes. The IC50 of patented inhibitors ranges between 0.82 µM and 8.95 µM, depending upon the assays used. Considering the urgency of clinical interventions against Coronavirus Disease-19 (COVID-19), it is important to consider developing antiviral portfolios consisting of small molecules.Areas covered: This review examines coronavirus helicases as antiviral targets, and the potential of previously patented and experimental compounds to inhibit the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) helicase.Expert opinion: Small molecule coronavirus helicase inhibitors represent attractive pharmacological modalities for the treatment of coronaviruses such as SARS-CoV and SARS-CoV-2. Rightfully so, the current emphasis is focused upon the development of vaccines. However, vaccines may not work for everyone and broad-based adoption of vaccinations is an increasingly challenging societal endeavor. Therefore, it is important to develop additional pharmacological antivirals against the highly conserved coronavirus helicases to broadly protect against this and subsequent coronavirus epidemics.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Drug Development , Methyltransferases/antagonists & inhibitors , RNA Helicases/antagonists & inhibitors , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Humans , Methyltransferases/chemistry , Methyltransferases/physiology , Patents as Topic , RNA Helicases/chemistry , RNA Helicases/physiology , Triazoles/pharmacology , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/physiology
10.
Arch Med Res ; 51(7): 733-735, 2020 10.
Article in English | MEDLINE | ID: covidwho-1023461

ABSTRACT

The discovery of new drugs for treating the new coronavirus (SARS-CoV-2) or repurposing those already in use for other viral infections is possible through understanding of the viral replication cycle and pathogenicity. This article highlights the advantage of targeting one of the non-structural proteins, helicase (nsp13), over other SARS-CoV-2 proteins. Highlighting the experience gained from targeting Nsp13 in similar coronaviruses (SARS-CoV and MERS) and known inhibitors, the article calls for research on helicase inhibitors as potential COVID-19 therapy.


Subject(s)
Antiviral Agents , COVID-19 , Enzyme Inhibitors , RNA Helicases/antagonists & inhibitors , SARS-CoV-2 , COVID-19/drug therapy , COVID-19/virology , Humans , Methyltransferases/antagonists & inhibitors , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Viral Nonstructural Proteins/antagonists & inhibitors
11.
Sci Signal ; 13(651)2020 09 29.
Article in English | MEDLINE | ID: covidwho-808027

ABSTRACT

There are currently no antiviral therapies specific for SARS-CoV-2, the virus responsible for the global pandemic disease COVID-19. To facilitate structure-based drug design, we conducted an x-ray crystallographic study of the SARS-CoV-2 nsp16-nsp10 2'-O-methyltransferase complex, which methylates Cap-0 viral mRNAs to improve viral protein translation and to avoid host immune detection. We determined the structures for nsp16-nsp10 heterodimers bound to the methyl donor S-adenosylmethionine (SAM), the reaction product S-adenosylhomocysteine (SAH), or the SAH analog sinefungin (SFG). We also solved structures for nsp16-nsp10 in complex with the methylated Cap-0 analog m7GpppA and either SAM or SAH. Comparative analyses between these structures and published structures for nsp16 from other betacoronaviruses revealed flexible loops in open and closed conformations at the m7GpppA-binding pocket. Bound sulfates in several of the structures suggested the location of the ribonucleic acid backbone phosphates in the ribonucleotide-binding groove. Additional nucleotide-binding sites were found on the face of the protein opposite the active site. These various sites and the conserved dimer interface could be exploited for the development of antiviral inhibitors.


Subject(s)
Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Methyltransferases/chemistry , Pneumonia, Viral/drug therapy , Viral Nonstructural Proteins/chemistry , Adenosine/analogs & derivatives , Adenosine/metabolism , Adenosine/pharmacology , Betacoronavirus/drug effects , Binding Sites , COVID-19 , Catalytic Domain , Crystallography, X-Ray , Dimerization , Genes, Viral/genetics , Humans , Methylation , Methyltransferases/antagonists & inhibitors , Models, Molecular , Open Reading Frames/genetics , Pandemics , Protein Binding , Protein Conformation , RNA Cap Analogs/metabolism , RNA Processing, Post-Transcriptional , RNA, Viral/metabolism , S-Adenosylhomocysteine/metabolism , S-Adenosylmethionine/metabolism , SARS-CoV-2 , Structure-Activity Relationship , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism
12.
Int J Biol Macromol ; 163: 1687-1696, 2020 Nov 15.
Article in English | MEDLINE | ID: covidwho-793718

ABSTRACT

SARS-CoV-2 has caused COVID-19 outbreak with nearly 2 M infected people and over 100K death worldwide, until middle of April 2020. There is no confirmed drug for the treatment of COVID-19 yet. As the disease spread fast and threaten human life, repositioning of FDA approved drugs may provide fast options for treatment. In this aspect, structure-based drug design could be applied as a powerful approach in distinguishing the viral drug target regions from the host. Evaluation of variations in SARS-CoV-2 genome may ease finding specific drug targets in the viral genome. In this study, 3458 SARS-CoV-2 genome sequences isolated from all around the world were analyzed. Incidence of C17747T and A17858G mutations were observed to be much higher than others and they were on Nsp13, a vital enzyme of SARS-CoV-2. Effect of these mutations was evaluated on protein-drug interactions using in silico methods. The most potent drugs were found to interact with the key and neighbor residues of the active site responsible from ATP hydrolysis. As result, cangrelor, fludarabine, folic acid and polydatin were determined to be the most potent drugs which have potency to inhibit both the wild type and mutant SARS-CoV-2 helicase. Clinical data supporting these findings would be important towards overcoming COVID-19.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Enzyme Inhibitors/pharmacology , Methyltransferases/antagonists & inhibitors , Pneumonia, Viral/drug therapy , RNA Helicases/antagonists & inhibitors , Viral Nonstructural Proteins/antagonists & inhibitors , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Amino Acid Sequence , Betacoronavirus/enzymology , Betacoronavirus/genetics , Binding Sites , COVID-19 , Computer Simulation , Coronavirus Infections/virology , Drug Approval , Drug Repositioning , Folic Acid/pharmacology , Genome, Viral , Glucosides/pharmacology , Humans , Methyltransferases/chemistry , Methyltransferases/genetics , Methyltransferases/metabolism , Molecular Docking Simulation , Mutation , Pandemics , Pneumonia, Viral/virology , RNA Helicases/chemistry , RNA Helicases/genetics , RNA Helicases/metabolism , SARS-CoV-2 , Stilbenes/pharmacology , Vidarabine/analogs & derivatives , Vidarabine/pharmacology , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism
13.
Life Sci ; 259: 118169, 2020 Oct 15.
Article in English | MEDLINE | ID: covidwho-684632

ABSTRACT

AIMS: The recent outbreak of pandemic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led the world towards a global health emergency. Currently, no proper medicine or effective treatment strategies are available; therefore, repurposing of FDA approved drugs may play an important role in overcoming the situation. MATERIALS AND METHODS: The SARS-CoV-2 genome encodes for 2-O-methyltransferase (2'OMTase), which plays a key role in methylation of viral RNA for evading host immune system. In the present study, the protein sequence of 2'OMTase of SARS-CoV-2 was analyzed, and its structure was modeled by a comparative modeling approach and validated. The library of 3000 drugs was screened against the active site of 2'OMTase followed by re-docking analysis. The apo and ligand-bound 2'OMTase were further validated and analyzed by using molecular dynamics simulation. KEY FINDINGS: The modeled structure displayed the conserved characteristic fold of class I MTase family. The quality assessment analysis by SAVES server reveals that the modeled structure follows protein folding rules and of excellent quality. The docking analysis displayed that the active site of 2'OMTase accommodates an array of drugs, which includes alkaloids, antivirals, cardiac glycosides, anticancer, steroids, and other drugs. The redocking and MD simulation analysis of the best 5 FDA approved drugs reveals that these drugs form a stable conformation with the 2'OMTase. SIGNIFICANCE: The results suggested that these drugs may be used as potential inhibitors for 2'OMTase for combating the SARS-CoV-2 infection.


Subject(s)
Betacoronavirus/drug effects , Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Methyltransferases/antagonists & inhibitors , Pneumonia, Viral/drug therapy , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19 , Computational Biology/methods , Coronavirus Infections/virology , Drug Repositioning/methods , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Humans , Methylation/drug effects , Methyltransferases/chemistry , Methyltransferases/metabolism , Methyltransferases/ultrastructure , Molecular Docking Simulation , Molecular Dynamics Simulation , Molecular Targeted Therapy , Pandemics , Pneumonia, Viral/virology , SARS-CoV-2 , Sequence Homology, Amino Acid
14.
Eur J Med Chem ; 201: 112557, 2020 Sep 01.
Article in English | MEDLINE | ID: covidwho-597389

ABSTRACT

The spreading of new viruses is known to provoke global human health threat. The current COVID-19 pandemic caused by the recently emerged coronavirus SARS-CoV-2 is one significant and unfortunate example of what the world will have to face in the future with emerging viruses in absence of appropriate treatment. The discovery of potent and specific antiviral inhibitors and/or vaccines to fight these massive outbreaks is an urgent research priority. Enzymes involved in the capping pathway of viruses and more specifically RNA N7- or 2'O-methyltransferases (MTases) are now admitted as potential targets for antiviral chemotherapy. We designed bisubstrate inhibitors by mimicking the transition state of the 2'-O-methylation of the cap RNA in order to block viral 2'-O MTases. This work resulted in the synthesis of 16 adenine dinucleosides with both adenosines connected by various nitrogen-containing linkers. Unexpectedly, all the bisubstrate compounds were barely active against 2'-O MTases of several flaviviruses or SARS-CoV but surprisingly, seven of them showed efficient and specific inhibition against SARS-CoV N7-MTase (nsp14) in the micromolar to submicromolar range. The most active nsp14 inhibitor identified is as potent as but particularly more specific than the broad-spectrum MTase inhibitor, sinefungin. Molecular docking suggests that the inhibitor binds to a pocket formed by the S-adenosyl methionine (SAM) and cap RNA binding sites, conserved among SARS-CoV nsp14. These dinucleoside SAM analogs will serve as starting points for the development of next inhibitors for SARS-CoV-2 nsp14 N7-MTase.


Subject(s)
Coronavirus Infections/drug therapy , Exoribonucleases/antagonists & inhibitors , Methyltransferases/antagonists & inhibitors , Nucleosides/chemistry , Pneumonia, Viral/drug therapy , RNA Caps/metabolism , S-Adenosylmethionine/analogs & derivatives , S-Adenosylmethionine/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Adenine/chemistry , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Exoribonucleases/metabolism , Humans , Methylation , Methyltransferases/metabolism , Molecular Docking Simulation , Pandemics , Pneumonia, Viral/metabolism , Pneumonia, Viral/virology , RNA Caps/chemistry , RNA Caps/genetics , RNA, Viral/genetics , RNA, Viral/metabolism , SARS-CoV-2 , Viral Nonstructural Proteins/metabolism
15.
Drugs ; 80(10): 941-946, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-361231

ABSTRACT

G-Quadruplexes (G4s) are non-canonical secondary structures formed within guanine-rich regions of DNA or RNA. G4 sequences/structures have been detected in human and in viral genomes, including Coronaviruses Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and SARS-CoV-2. Here, we outline the existing evidence indicating that G4 ligands and inhibitors of SARS-CoV-2 helicase may exert some antiviral activity reducing viral replication and can represent a potential therapeutic approach to tackle the COVID-19 pandemic due to SARS-CoV-2 infection. We also discuss how repositioning of FDA-approved drugs against helicase activity of other viruses, could represent a rapid strategy to limit deaths associated with COVID-19 pandemic.


Subject(s)
Antiviral Agents/therapeutic use , Betacoronavirus/genetics , Coronavirus Infections/drug therapy , G-Quadruplexes , Genome, Viral/genetics , Pneumonia, Viral/drug therapy , RNA Helicases/antagonists & inhibitors , COVID-19 , Coronavirus Papain-Like Proteases , Drug Repositioning , Humans , Methyltransferases/antagonists & inhibitors , Pandemics , SARS-CoV-2 , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism
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