scholarly journals Natural plant products as potential inhibitors of RNA dependent RNA polymerase of Severe Acute Respiratory Syndrome Coronavirus-2

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251801
Author(s):  
Shruti Koulgi ◽  
Vinod Jani ◽  
Mallikarjunachari Uppuladinne V. N. ◽  
Uddhavesh Sonavane ◽  
Rajendra Joshi

Drug repurposing studies targeting inhibition of RNA dependent RNA polymerase (RdRP) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) have exhibited the potential effect of small molecules. In the present work a detailed interaction study between the phytochemicals from Indian medicinal plants and the RdRP of SARS-CoV-2 has been performed. The top four phytochemicals obtained through molecular docking were, swertiapuniside, cordifolide A, sitoindoside IX, and amarogentin belonging to Swertia chirayita, Tinospora cordifolia and Withania somnifera. These ligands bound to the RdRP were further studied using molecular dynamics simulations. The principal component analysis of these systems showed significant conformational changes in the finger and thumb subdomain of the RdRP. Hydrogen bonding, salt-bridge and water mediated interactions supported by MM-GBSA free energy of binding revealed strong binding of cordifolide A and sitoindoside IX to RdRP. The ligand-interacting residues belonged to either of the seven conserved motifs of the RdRP. These residues were polar and charged amino acids, namely, ARG 553, ARG 555, ASP 618, ASP 760, ASP 761, GLU 811, and SER 814. The glycosidic moieties of the phytochemicals were observed to form favourable interactions with these residues. Hence, these phytochemicals may hold the potential to act as RdRP inhibitors owing to their stability in binding to the druggable site.

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1166
Author(s):  
Krishnaprasad Baby ◽  
Swastika Maity ◽  
Chetan H. Mehta ◽  
Akhil Suresh ◽  
Usha Y. Nayak ◽  
...  

Background: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), took more lives than combined epidemics of SARS, MERS, H1N1, and Ebola. Currently, the prevention and control of spread are the goals in COVID-19 management as there are no specific drugs to cure or vaccines available for prevention. Hence, the drug repurposing was explored by many research groups, and many target proteins have been examined. The major protease (Mpro), and RNA-dependent RNA polymerase (RdRp) are two target proteins in SARS-CoV-2 that have been validated and extensively studied for drug development in COVID-19. The RdRp shares a high degree of homology between those of two previously known coronaviruses, SARS-CoV and MERS-CoV. Methods: In this study, the FDA approved library of drugs were docked against the active site of RdRp using Schrodinger's computer-aided drug discovery tools for in silico drug-repurposing. Results: We have shortlisted 14 drugs from the Standard Precision docking and interaction-wise study of drug-binding with the active site on the enzyme. These drugs are antibiotics, NSAIDs, hypolipidemic, coagulant, thrombolytic, and anti-allergics. In molecular dynamics simulations, pitavastatin, ridogrel and rosoxacin displayed superior binding with the active site through ARG555 and divalent magnesium. Conclusion: Pitavastatin, ridogrel and rosoxacin can be further optimized in preclinical and clinical studies to determine their possible role in COVID-19 treatment.


RSC Advances ◽  
2020 ◽  
Vol 10 (45) ◽  
pp. 26792-26803 ◽  
Author(s):  
Shruti Koulgi ◽  
Vinod Jani ◽  
Mallikarjunachari V. N. Uppuladinne ◽  
Uddhavesh Sonavane ◽  
Rajendra Joshi

Conformational changes in the remdesivir-bound RdRP leading to its inhibition.


2021 ◽  
Vol 8 ◽  
Author(s):  
Vijay Kumar Bhardwaj ◽  
Rahul Singh ◽  
Jatin Sharma ◽  
Vidya Rajendran ◽  
Rituraj Purohit ◽  
...  

The coronavirus disease (COVID-19), a worldwide pandemic, is caused by the severe acute respiratory syndrome-corona virus-2 (SARS-CoV-2). At this moment in time, there are no specific therapeutics available to combat COVID-19. Drug repurposing and identification of naturally available bioactive molecules to target SARS-CoV-2 are among the key strategies to tackle the notorious virus. The enzyme RNA-dependent RNA polymerase (RdRp) performs a pivotal role in replicating the virus. RdRp is a prime target for Remdesivir and other nucleotides analog-based antiviral drugs. In this study, we showed three bioactive molecules from tea (epicatechin-3,5-di-O-gallate, epigallocatechin-3,5-di-O-gallate, and epigallocatechin-3,4-di-O-gallate) that showed better interaction with critical residues present at the catalytic center and the NTP entry channel of RdRp than antiviral drugs Remdesivir and Favipiravir. Our computational approach to identify these molecules included molecular docking studies, followed by robust molecular dynamics simulations. All the three molecules are readily available in tea and could be made accessible along with other medications to treat COVID-19 patients. However, these results require validation by further in vitro and in vivo studies.


2021 ◽  
Vol 28 ◽  
Author(s):  
Shabana Bibi ◽  
Mohammad Mehedi Hasan ◽  
Yuan-Bing Wang ◽  
Stavros P. Papadakos ◽  
Hong Yu

Background: SARS-CoV-2, which emerged in Wuhan, China, is a new global threat that has killed millions of people and continues to do so. This pandemic has not only threatened human life but has also triggered economic downturns across the world. Researchers have made significant strides in discovering molecular insights into SARS-CoV-2 pathogenesis and developing vaccines, but there is still no successful cure for SARS-CoV-2 infected patients. Objective: The present study has proposed a drug-repositioning pipeline for the design and discovery of an effective fungal-derived bioactive metabolite as a drug candidate against SARS-CoV-2. Methods: Fungal derivative “Cordycepin” was selected for this study to investigate the inhibitory properties against RNA-dependent RNA polymerase (RdRp) (PDB ID: 6M71) of SARS-CoV-2. The pharmacological profile, intermolecular interactions, binding energy, and stability of the compound were determined utilizing cheminformatic approaches. Subsequently, molecular dynamic simulation was performed to better understand the binding mechanism of cordycepin to RdRp. Results: The pharmacological data and retrieved molecular dynamics simulations trajectories suggest excellent drug-likeliness and greater structural stability of cordycepin, while the catalytic residues (Asp760, Asp761), as well as other active site residues (Trp617, Asp618, Tyr619, Trp800, Glu811) of RdRp, showed better stability during the overall simulation span. Conclusion: Promising results of pharmacological investigation along with molecular simulations revealed that cordycepin exhibited strong inhibitory potential against SARS-CoV-2 polymerase enzyme (RdRp). Hence, cordycepin should be highly recommended to test in a laboratory to confirm its inhibitory potential against the SARS-CoV-2 polymerase enzyme (RdRp).


2014 ◽  
Vol 70 (a1) ◽  
pp. C1595-C1595
Author(s):  
Kenneth Ng ◽  
Dmitry Zamyatkin ◽  
Hayeong Rho ◽  
Elesha Hoffarth ◽  
Gabriela Jurca ◽  
...  

Human Noroviruses (NV) belong in the Caliciviridae family and are a major cause of gastroenteritis outbreaks throughout the world. Crystal structures of the RNA-dependent RNA polymerase from the human Norovirus have been determined in over ten different crystal forms in the presence and absence of divalent metal cations, nucleoside triphosphates, inhibitors and primer-template duplex RNA. These structures show how the polymerase enzyme can adopt a range of conformations in which the thumb, fingers and palm domains change orientations depending on the step of the enzymatic cycle trapped in different crystal forms. We discuss how the evidence from crystallographic and biochemical experiments combine to better understand how viral RNA polymerase enzymes from human Norovirus and related positive-strand RNA viruses can adopt a range of conformational states to facilitate RNA binding, NTP binding, catalysis, RNA translocation and pyrophosphate release. The detailed structural and mechanistic understanding of these conformational changes is important for providing a sound basis for understanding viral replication in general, as well as for the design of novel inhibitors capable of trapping the enzyme in specific conformational states.


2020 ◽  
Vol 295 (20) ◽  
pp. 6785-6797 ◽  
Author(s):  
Calvin J. Gordon ◽  
Egor P. Tchesnokov ◽  
Emma Woolner ◽  
Jason K. Perry ◽  
Joy Y. Feng ◽  
...  

Effective treatments for coronavirus disease 2019 (COVID-19) are urgently needed to control this current pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Replication of SARS-CoV-2 depends on the viral RNA-dependent RNA polymerase (RdRp), which is the likely target of the investigational nucleotide analogue remdesivir (RDV). RDV shows broad-spectrum antiviral activity against RNA viruses, and previous studies with RdRps from Ebola virus and Middle East respiratory syndrome coronavirus (MERS-CoV) have revealed that delayed chain termination is RDV's plausible mechanism of action. Here, we expressed and purified active SARS-CoV-2 RdRp composed of the nonstructural proteins nsp8 and nsp12. Enzyme kinetics indicated that this RdRp efficiently incorporates the active triphosphate form of RDV (RDV-TP) into RNA. Incorporation of RDV-TP at position i caused termination of RNA synthesis at position i+3. We obtained almost identical results with SARS-CoV, MERS-CoV, and SARS-CoV-2 RdRps. A unique property of RDV-TP is its high selectivity over incorporation of its natural nucleotide counterpart ATP. In this regard, the triphosphate forms of 2′-C-methylated compounds, including sofosbuvir, approved for the management of hepatitis C virus infection, and the broad-acting antivirals favipiravir and ribavirin, exhibited significant deficits. Furthermore, we provide evidence for the target specificity of RDV, as RDV-TP was less efficiently incorporated by the distantly related Lassa virus RdRp, and termination of RNA synthesis was not observed. These results collectively provide a unifying, refined mechanism of RDV-mediated RNA synthesis inhibition in coronaviruses and define this nucleotide analogue as a direct-acting antiviral.


2018 ◽  
Vol 92 (22) ◽  
Author(s):  
Weike Li ◽  
Ryan H. Gumpper ◽  
Yusuf Uddin ◽  
Ingeborg Schmidt-Krey ◽  
Ming Luo

ABSTRACTDuring viral RNA synthesis by the viral RNA-dependent RNA polymerase (vRdRp) of vesicular stomatitis virus, the sequestered RNA genome must be released from the nucleocapsid in order to serve as the template. Unveiling the sequestered RNA by interactions of vRdRp proteins, the large subunit (L) and the phosphoprotein (P), with the nucleocapsid protein (N) must not disrupt the nucleocapsid assembly. We noticed that a flexible structural motif composed of an α-helix and a loop in the N protein may act as the access gate to the sequestered RNA. This suggests that local conformational changes in this structural motif may be induced by interactions with the polymerase to unveil the sequestered RNA, without disrupting the nucleocapsid assembly. Mutations of several residues in this structural motif—Glu169, Phe171, and Leu174—to Ala resulted in loss of viral RNA synthesis in a minigenome assay. After implementing these mutations in the viral genome, mutant viruses were recovered by reverse genetics and serial passages. Sequencing the genomes of the mutant viruses revealed that compensatory mutations in L, P, and N were required to restore the viral viability. Corresponding mutations were introduced in L, P, and N, and their complementarity to the N mutations was confirmed by the minigenome assay. Introduction of the corresponding mutations is also sufficient to rescue the mutant viruses. These results suggested that the interplay of the N structural motif with the L protein may play a role in accessing the nucleotide template without disrupting the overall structure of the nucleocapsid.IMPORTANCEDuring viral RNA synthesis of a negative-strand RNA virus, the viral RNA-dependent RNA polymerase (vRdRp) must gain access to the sequestered RNA in the nucleocapsid to use it as the template, but at the same time may not disrupt the nucleocapsid assembly. Our structural and mutagenesis studies showed that a flexible structural motif acts as a potential access gate to the sequestered RNA and plays an essential role in viral RNA synthesis. Interactions of this structural motif within the vRdRp may be required for unveiling the sequestered RNA. This mechanism of action allows the sequestered RNA to be released locally without disrupting the overall structure of the nucleocapsid. Since this flexible structural motif is present in the N proteins of many NSVs, release of the sequestered RNA genome by local conformational changes in the N protein may be a general mechanism in NSV viral RNA synthesis.


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