scholarly journals Baicalein and Baicalin Inhibit SARS-CoV-2 RNA-Dependent-RNA Polymerase

2021 ◽  
Vol 9 (5) ◽  
pp. 893
Author(s):  
Keivan Zandi ◽  
Katie Musall ◽  
Adrian Oo ◽  
Dongdong Cao ◽  
Bo Liang ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Specific Binding ◽  
Antiviral Agents ◽  
Potential Candidate ◽  
Rna Dependent Rna Polymerase ◽  
Antiviral Therapies ◽  
Global Pandemic ◽  
Therapeutic Development ◽  
Polymerase Inhibitor

Coronavirus Disease 2019 (COVID-19) is a deadly emerging infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Because SARS-CoV-2 is easily transmitted through the air and has a relatively long incubation time, COVID-19 has rapidly developed into a global pandemic. As there are no antiviral agents for the prevention and treatment of this severe pathogen except for remdesivir, development of antiviral therapies to treat infected individuals remains highly urgent. Here, we showed that baicalein and baicalin exhibited significant antiviral activity against SARS-CoV-2, the causative agent of COVID-19 through in vitro studies. Our data through cell-based and biochemical studies showed that both compounds act as SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibitors directly and inhibit the activity of the SARS-CoV-2 RdRp, but baicalein was more potent. We also showed specific binding of baicalein to the SARS-CoV-2 RdRp, making it a potential candidate for further studies towards therapeutic development for COVID-19 as a selective non-nucleoside polymerase inhibitor.

scholarly journals Vaccines and Treatment of Coronavirus Disease 2019

2020 ◽  
Vol 95 (6) ◽  
pp. 364-369
Author(s):  
Pyoeng Gyun Choe
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Antiviral Agents ◽  
World Health ◽  
Rna Dependent Rna Polymerase ◽  
Global Pandemic ◽  
The World ◽  
Polymerase Inhibitor ◽  
Experimental Treatments ◽  
Health Organization

In December 2019, a new strain of betacoronavirus, severe acute respiratory syndrome coronavirus 2, which causes coronavirus disease 2019 (COVID-19), emerged in Wuhan, China. Subsequently, the virus quickly spread worldwide and the World Health Organization declared COVID-19 a global pandemic on March 11, 2020. In response to the pandemic, many researchers are working on repurposing existing drugs to alter the course of severe COVID-19, and are testing experimental treatments. Among antiviral agents, remdesivir, an RNA-dependent RNA polymerase inhibitor, showed clinical benefit in a randomized clinical trial. In October 2020, the Food and Drug Administration approved remdesivir for treating hospitalized patients with COVID-19, making it the first drug approved for the disease. The race to produce safe, effective vaccines is also progressing at unprecedented speed, with over 200 under development and 45 candidates already being tested in human clinical trials (as of October 2020).

scholarly journals Fast and efficient purification of SARS-CoV-2 RNA dependent RNA polymerase complex expressed in Escherichia coli

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250610
Author(s):  
Clément Madru ◽  
Ayten Dizkirici Tekpinar ◽  
Sandrine Rosario ◽  
Dariusz Czernecki ◽  
Sébastien Brûlé ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Insect Cells ◽  
Antiviral Agents ◽  
Chemical Compounds ◽  
Rna Dependent Rna Polymerase ◽  
Rna Polymerization ◽  
Purification Protocol ◽  
Transcription And Replication

To stop the COVID-19 pandemic due to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which caused more than 2.5 million deaths to date, new antiviral molecules are urgently needed. The replication of SARS-CoV-2 requires the RNA-dependent RNA polymerase (RdRp), making RdRp an excellent target for antiviral agents. RdRp is a multi-subunit complex composed of 3 viral proteins named nsp7, nsp8 and nsp12 that ensure the ~30 kb RNA genome’s transcription and replication. The main strategies employed so far for the overproduction of RdRp consist of expressing and purifying the three subunits separately before assembling the complex in vitro. However, nsp12 shows limited solubility in bacterial expression systems and is often produced in insect cells. Here, we describe an alternative strategy to co-express the full SARS-CoV-2 RdRp in E. coli, using a single plasmid. Characterization of the purified recombinant SARS-CoV-2 RdRp shows that it forms a complex with the expected (nsp7)(nsp8)2(nsp12) stoichiometry. RNA polymerization activity was measured using primer-extension assays showing that the purified enzyme is functional. The purification protocol can be achieved in one single day, surpassing in speed all other published protocols. Our construct is ideally suited for screening RdRp and its variants against very large chemical compounds libraries and has been made available to the scientific community through the Addgene plasmid depository (Addgene ID: 165451).

scholarly journals Preclinical Characterization of JTK-853, a Novel Nonnucleoside Inhibitor of the Hepatitis C Virus RNA-Dependent RNA Polymerase

2012 ◽  
Vol 56 (8) ◽  
pp. 4250-4256 ◽  
Author(s):  
Izuru Ando ◽  
Tsuyoshi Adachi ◽  
Naoki Ogura ◽  
Yukiyo Toyonaga ◽  
Kazuyuki Sugimoto ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Antiviral Activity ◽  
Rna Polymerase ◽  
Antiviral Agents ◽  
Hcv Rna ◽  
Resistance Mutations ◽  
Rna Dependent Rna Polymerase ◽  
Virus Rna ◽  
Polymerase Inhibitor

ABSTRACTJTK-853 is a novel piperazine derivative nonnucleoside inhibitor of hepatitis C virus (HCV) RNA-dependent RNA polymerase. JTK-853 showed potent inhibitory activity against genotype 1 HCV polymerase, with a 50% inhibitory concentration in the nanomolar range, and showed potent antiviral activity against the genotype 1b replicon, with a 50% effective concentration of 0.035 μM. The presence of human serum at up to 40% had little effect on the antiviral activity of JTK-853. Structure analysis of HCV polymerase with JTK-853 revealed that JTK-853 associates with the palm site and β-hairpin region of HCV polymerase, and JTK-853 showed decreased antiviral activity against HCV replicons bearing the resistance mutations C316Y, M414T, Y452H, and L466V in the palm site region of HCV polymerase. JTK-853 showed an additive combination effect with other DAAs (direct antiviral agents), such as nucleoside polymerase inhibitor, thumb pocket-binding nonnucleoside polymerase inhibitor, NS5A inhibitor, and protease inhibitor. Collectively, these data demonstrate that JTK-853 is a potent and novel nonnucleoside palm site-binding HCV polymerase inhibitor, suggesting JTK-853 as a potentially useful agent in combination with other DAAs for treatment of HCV infections.

scholarly journals Inhibitors of Respiratory Syncytial Virus Replication Target Cotranscriptional mRNA Guanylylation by Viral RNA-Dependent RNA Polymerase

2005 ◽  
Vol 79 (20) ◽  
pp. 13105-13115 ◽  
Author(s):  
Michel Liuzzi ◽  
Stephen W. Mason ◽  
Mireille Cartier ◽  
Carol Lawetz ◽  
Robert S. McCollum ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Rna Polymerase ◽  
High Throughput Screening ◽  
Antiviral Agents ◽  
Respiratory Illness ◽  
The Elderly ◽  
Transcriptase Inhibitor ◽  
Rna Dependent Rna Polymerase ◽  
Syncytial Virus

ABSTRACT Respiratory syncytial virus (RSV) is a major cause of respiratory illness in infants, immunocompromised patients, and the elderly. New antiviral agents would be important tools in the treatment of acute RSV disease. RSV encodes its own RNA-dependent RNA polymerase that is responsible for the synthesis of both genomic RNA and subgenomic mRNAs. The viral polymerase also cotranscriptionally caps and polyadenylates the RSV mRNAs at their 5′ and 3′ ends, respectively. We have previously reported the discovery of the first nonnucleoside transcriptase inhibitor of RSV polymerase through high-throughput screening. Here we report the design of inhibitors that have improved potency both in vitro and in antiviral assays and that also exhibit activity in a mouse model of RSV infection. We have isolated virus with reduced susceptibility to this class of inhibitors. The mutations conferring resistance mapped to a novel motif within the RSV L gene, which encodes the catalytic subunit of RSV polymerase. This motif is distinct from the catalytic region of the L protein and bears some similarity to the nucleotide binding domain within nucleoside diphosphate kinases. These findings lead to the hypothesis that this class of inhibitors may block synthesis of RSV mRNAs by inhibiting guanylylation of viral transcripts. We show that short transcripts produced in the presence of inhibitor in vitro do not contain a 5′ cap but, instead, are triphosphorylated, confirming this hypothesis. These inhibitors constitute useful tools for elucidating the molecular mechanism of RSV capping and represent valid leads for the development of novel anti-RSV therapeutics.

Recent Advances towards Drug Design Targeting the Protease of 2019 novel coronavirus (2019-nCoV)

2020 ◽  
Vol 27 ◽  
Author(s):  
Sehrish Bano ◽  
Abdul Hameed ◽  
Mariya Al-Rashida ◽  
Shafia Iftikhar ◽  
Jamshed Iqbal
Keyword(s):  
Drug Design ◽  
Rna Polymerase ◽  
Drug Targets ◽  
Antiviral Agents ◽  
Structural Features ◽  
Antiviral Drugs ◽  
Rna Dependent Rna Polymerase ◽  
Mortality And Morbidity ◽  
Functional Relationships ◽  
Novel Coronavirus

Background: The 2019 novel coronavirus (2019-nCoV), also known as coronavirus 2 (SARS-CoV-2) acute respiratory syndrome has recently emerged and continued to spread rapidly with high level of mortality and morbidity rates. Currently, no efficacious therapy is available to relieve coronavirus infections. As new drug design and development takes much time, there is a possibility to find an effective treatment from existing antiviral agents. Objective: In this case, there is a need to find out the relationship between possible drug targets and mechanism of action of antiviral drugs. This review discusses about the efforts to develop drug from known or new molecules. Methods: Viruses usually have two structural integrities, proteins and nucleic acids, both of which can be possible drug targets. Herein, we systemically discuss the structural-functional relationships of the spike, 3-chymotrypsin-like protease (3CLpro), papain like protease (PLpro) and RNA-dependent RNA polymerase (RdRp), as these are prominent structural features of corona virus. Certain antiviral drugs such as Remdesivir are RNA dependent RNA polymerase inhibitor. It has the ability to terminate RNA replication by inhibiting ATP. Results: It is reported that ATP is involved in synthesis of coronavirus non-structural proteins from 3CLpro and PLpro. Similarly, mechanisms of action of many other antiviral agents has been discussed in this review. It will provide new insights into the mechanism of inhibition, and let us develop new therapeutic antiviral approaches against novel SARS-CoV-2 coronavirus. Conclusion: In conclusion, this review summarizes recent progress in developing protease inhibitors for SARS-CoV-2.

scholarly journals Analysis of Ribonucleotide 5′-Triphosphate Analogs as Potential Inhibitors of Zika Virus RNA-Dependent RNA Polymerase by Using Nonradioactive Polymerase Assays

2016 ◽  
Vol 61 (3) ◽  
Author(s):  
Gaofei Lu ◽  
Gregory R. Bluemling ◽  
Paul Collop ◽  
Michael Hager ◽  
Damien Kuiper ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Zika Virus ◽  
Nonstructural Protein ◽  
Rna Dependent Rna Polymerase ◽  
Antiviral Compounds ◽  
Double Stranded Dna ◽  
Virus Rna ◽  
Potential Inhibitors

ABSTRACT Zika virus (ZIKV) is an emerging human pathogen that is spreading rapidly through the Americas and has been linked to the development of microcephaly and to a dramatically increased number of Guillain-Barré syndrome cases. Currently, no vaccine or therapeutic options for the prevention or treatment of ZIKV infections exist. In the study described in this report, we expressed, purified, and characterized full-length nonstructural protein 5 (NS5) and the NS5 polymerase domain (NS5pol) of ZIKV RNA-dependent RNA polymerase. Using purified NS5, we developed an in vitro nonradioactive primer extension assay employing a fluorescently labeled primer-template pair. Both purified NS5 and NS5pol can carry out in vitro RNA-dependent RNA synthesis in this assay. Our results show that Mn2+ is required for enzymatic activity, while Mg2+ is not. We found that ZIKV NS5 can utilize single-stranded DNA but not double-stranded DNA as a template or a primer to synthesize RNA. The assay was used to compare the efficiency of incorporation of analog 5′-triphosphates by the ZIKV polymerase and to calculate their discrimination versus that of natural ribonucleotide triphosphates (rNTPs). The 50% inhibitory concentrations for analog rNTPs were determined in an alternative nonradioactive coupled-enzyme assay. We determined that, in general, 2′-C-methyl- and 2′-C-ethynyl-substituted analog 5′-triphosphates were efficiently incorporated by the ZIKV polymerase and were also efficient chain terminators. Derivatives of these molecules may serve as potential antiviral compounds to be developed to combat ZIKV infection. This report provides the first characterization of ZIKV polymerase and demonstrates the utility of in vitro polymerase assays in the identification of potential ZIKV inhibitors.

scholarly journals RNA-Dependent RNA Polymerase from Heterobasidion RNA Virus 6 Is an Active Replicase In Vitro

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1738
Author(s):  
Alesia A. Levanova ◽  
Eeva J. Vainio ◽  
Jarkko Hantula ◽  
Minna M. Poranen
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Rna Virus ◽  
Polymerization Reaction ◽  
Rna Dependent Rna Polymerase ◽  
Independent Manner ◽  
Nucleotidyl Transferase ◽  
Rna Polymerization ◽  
The Family

Heterobasidion RNA virus 6 (HetRV6) is a double-stranded (ds)RNA mycovirus and a member of the recently established genus Orthocurvulavirus within the family Orthocurvulaviridae. The purpose of the study was to determine the biochemical requirements for RNA synthesis catalyzed by HetRV6 RNA-dependent RNA polymerase (RdRp). HetRV6 RdRp was expressed in Escherichia coli and isolated to near homogeneity using liquid chromatography. The enzyme activities were studied in vitro using radiolabeled UTP. The HetRV6 RdRp was able to initiate RNA synthesis in a primer-independent manner using both virus-related and heterologous single-stranded (ss)RNA templates, with a polymerization rate of about 46 nt/min under optimal NTP concentration and temperature. NTPs with 2′-fluoro modifications were also accepted as substrates in the HetRV6 RdRp-catalyzed RNA polymerization reaction. HetRV6 RdRp transcribed viral RNA genome via semi-conservative mechanism. Furthermore, the enzyme demonstrated terminal nucleotidyl transferase (TNTase) activity. Presence of Mn2+ was required for the HetRV6 RdRp catalyzed enzymatic activities. In summary, our study shows that HetRV6 RdRp is an active replicase in vitro that can be potentially used in biotechnological applications, molecular biology, and biomedicine.

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