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A natural product compound inhibits coronaviral replication in vitro by binding to the conserved Nsp9 SARS-CoV-2 protein. J Biol Chem 2021; 297:101362. [PMID: 34756886 PMCID: PMC8553373 DOI: 10.1016/j.jbc.2021.101362] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/18/2021] [Accepted: 10/26/2021] [Indexed: 01/18/2023] Open
Abstract
The Nsp9 replicase is a conserved coronaviral protein that acts as an essential accessory component of the multi-subunit viral replication/transcription complex. Nsp9 is the predominant substrate for the essential nucleotidylation activity of Nsp12. Compounds specifically interfering with this viral activity would facilitate its study. Using a native mass-spectrometry-based approach to screen a natural product library for Nsp9 binders, we identified an ent-kaurane natural product, oridonin, capable of binding to purified SARS-CoV-2 Nsp9 with micromolar affinities. By determining the crystal structure of the Nsp9-oridonin complex, we showed that oridonin binds through a conserved site near Nsp9’s C-terminal GxxxG-helix. In enzymatic assays, oridonin’s binding to Nsp9 reduces its potential to act as substrate for Nsp12’s Nidovirus RdRp-Associated Nucleotidyl transferase (NiRAN) domain. We also showed using in vitro cellular assays oridonin, while cytotoxic at higher doses has broad antiviral activity, reducing viral titer following infection with either SARS-CoV-2 or, to a lesser extent, MERS-CoV. Accordingly, these preliminary findings suggest that the oridonin molecular scaffold may have the potential to be developed into an antiviral compound to inhibit the function of Nsp9 during coronaviral replication.
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52
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Osinski A, Black MH, Pawłowski K, Chen Z, Li Y, Tagliabracci VS. Structural and mechanistic basis for protein glutamylation by the kinase fold. Mol Cell 2021; 81:4527-4539.e8. [PMID: 34407442 DOI: 10.1016/j.molcel.2021.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 12/12/2022]
Abstract
The kinase domain transfers phosphate from ATP to substrates. However, the Legionella effector SidJ adopts a kinase fold, yet catalyzes calmodulin (CaM)-dependent glutamylation to inactivate the SidE ubiquitin ligases. The structural and mechanistic basis in which the kinase domain catalyzes protein glutamylation is unknown. Here we present cryo-EM reconstructions of SidJ:CaM:SidE reaction intermediate complexes. We show that the kinase-like active site of SidJ adenylates an active-site Glu in SidE, resulting in the formation of a stable reaction intermediate complex. An insertion in the catalytic loop of the kinase domain positions the donor Glu near the acyl-adenylate for peptide bond formation. Our structural analysis led us to discover that the SidJ paralog SdjA is a glutamylase that differentially regulates the SidE ligases during Legionella infection. Our results uncover the structural and mechanistic basis in which the kinase fold catalyzes non-ribosomal amino acid ligations and reveal an unappreciated level of SidE-family regulation.
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Affiliation(s)
- Adam Osinski
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Miles H Black
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Krzysztof Pawłowski
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Institute of Biology, Warsaw University of Life Sciences, Warsaw 02-787, Poland
| | - Zhe Chen
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yang Li
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Vincent S Tagliabracci
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Abstract
The ongoing Covid-19 pandemic has spurred research in the biology of the nidovirus severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Much focus has been on the viral RNA synthesis machinery due to its fundamental role in viral propagation. The central and essential enzyme of the RNA synthesis process, the RNA-dependent RNA polymerase (RdRp), functions in conjunction with a coterie of viral-encoded enzymes that mediate crucial nucleic acid transactions. Some of these enzymes share common features with other RNA viruses, while others play roles unique to nidoviruses or CoVs. The RdRps are proven targets for viral pathogens, and many of the other nucleic acid processing enzymes are promising targets. The purpose of this review is to summarize recent advances in our understanding of the mechanisms of RNA synthesis in CoVs. By reflecting on these studies, we hope to emphasize the remaining gaps in our knowledge. The recent onslaught of structural information related to SARS-CoV-2 RNA synthesis, in combination with previous structural, genetic and biochemical studies, have vastly improved our understanding of how CoVs replicate and process their genomic RNA. Structural biology not only provides a blueprint for understanding the function of the enzymes and cofactors in molecular detail, but also provides a basis for drug design and optimization. The concerted efforts of researchers around the world, in combination with the renewed urgency toward understanding this deadly family of viruses, may eventually yield new and improved antivirals that provide relief to the current global devastation.
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Affiliation(s)
- Brandon Malone
- The Rockefeller University, New York, New York, United States
| | | | - Seth A Darst
- The Rockefeller University, New York, New York, United States.
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Perry JK, Appleby TC, Bilello JP, Feng JY, Schmitz U, Campbell EA. An atomistic model of the coronavirus replication-transcription complex as a hexamer assembled around nsp15. J Biol Chem 2021; 297:101218. [PMID: 34562452 PMCID: PMC8494237 DOI: 10.1016/j.jbc.2021.101218] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/23/2022] Open
Abstract
The SARS-CoV-2 replication-transcription complex is an assembly of nonstructural viral proteins that collectively act to reproduce the viral genome and generate mRNA transcripts. While the structures of the individual proteins involved are known, how they assemble into a functioning superstructure is not. Applying molecular modeling tools, including protein-protein docking, to the available structures of nsp7-nsp16 and the nucleocapsid, we have constructed an atomistic model of how these proteins associate. Our principal finding is that the complex is hexameric, centered on nsp15. The nsp15 hexamer is capped on two faces by trimers of nsp14/nsp16/(nsp10)2, which then recruit six nsp12/nsp7/(nsp8)2 polymerase subunits to the complex. To this, six subunits of nsp13 are arranged around the superstructure, but not evenly distributed. Polymerase subunits that coordinate dimers of nsp13 are capable of binding the nucleocapsid, which positions the 5'-UTR TRS-L RNA over the polymerase active site, a state distinguishing transcription from replication. Analysis of the viral RNA path through the complex indicates the dsRNA that exits the polymerase passes over the nsp14 exonuclease and nsp15 endonuclease sites before being unwound by a convergence of zinc fingers from nsp10 and nsp14. The template strand is then directed away from the complex, while the nascent strand is directed to the sites responsible for mRNA capping. The model presents a cohesive picture of the multiple functions of the coronavirus replication-transcription complex and addresses fundamental questions related to proofreading, template switching, mRNA capping, and the role of the endonuclease.
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Affiliation(s)
| | | | | | - Joy Y Feng
- Gilead Sciences, Inc, Foster City, California, USA
| | - Uli Schmitz
- Gilead Sciences, Inc, Foster City, California, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, New York, USA
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55
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Does immune recognition of SARS-CoV2 epitopes vary between different ethnic groups? Virus Res 2021; 305:198579. [PMID: 34560183 PMCID: PMC8453877 DOI: 10.1016/j.virusres.2021.198579] [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: 05/10/2021] [Revised: 09/09/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022]
Abstract
The SARS-CoV2 mediated Covid-19 pandemic has impacted humankind at an unprecedented scale. While substantial research efforts have focused towards understanding the mechanisms of viral infection and developing vaccines/ therapeutics, factors affecting the susceptibility to SARS-CoV2 infection and manifestation of Covid-19 remain less explored. Given that the Human Leukocyte Antigen (HLA) system is known to vary among ethnic populations, it is likely to affect the recognition of the virus, and in turn, the susceptibility to Covid-19. To understand this, we used bioinformatic tools to probe all SARS-CoV2 peptides which could elicit T-cell response in humans. We also tried to answer the intriguing question of whether these potential epitopes were equally immunogenic across ethnicities, by studying the distribution of HLA alleles among different populations and their share of cognate epitopes. Results indicate that the immune recognition potential of SARS-CoV2 epitopes tend to vary between different ethnic groups. While the South Asians are likely to recognize higher number of CD8-specific epitopes, Europeans are likely to identify higher number of CD4-specific epitopes. We also hypothesize and provide clues that the newer mutations in SARS-CoV2 are unlikely to alter the T-cell mediated immunogenic responses among the studied ethnic populations. The work presented herein is expected to bolster our understanding of the pandemic, by providing insights into differential immunological response of ethnic populations to the virus as well as by gaging the possible effects of mutations in SARS-CoV2 on efficacy of potential epitope-based vaccines through evaluating ∼40,000 viral genomes.
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Sonkar C, Doharey PK, Rathore AS, Singh V, Kashyap D, Sahoo AK, Mittal N, Sharma B, Jha HC. Repurposing of gastric cancer drugs against COVID-19. Comput Biol Med 2021; 137:104826. [PMID: 34537409 PMCID: PMC8420180 DOI: 10.1016/j.compbiomed.2021.104826] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 12/19/2022]
Abstract
Corona Virus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has become a global pandemic. Additionally, the SARS-CoV-2 infection in the patients of Gastric Cancer (GC; the third leading cause of death in the world) pose a great challenge for the health management of the patients. Since there have been uncertainties to develop a new drug against COVID-19, there is an urgent need for repurposing drugs that can target key proteins of both SARS-CoV-2 and GC. The SARS-CoV-2-RdRp protein contains the NiRAN domain, which is known to have kinase-like folds. A docking study of the FDA approved drugs against GC was performed using AutoDock 4.2 and Glide Schrodinger suite 2019 against SARS-CoV-2-RdRp protein. MMGBSA and MD simulation studies were performed to investigate the binding and stability of the inhibitors with the target protein. In this study, we have found 12 kinase inhibitors with high binding energies namely Baricitinib, Brepocitinib, Decernotinib, Fasudil, Filgotinib, GSK2606414, Peficitinib, Ruxolitinib, Tofacitinib, Upadacitinib, Pamapimod and Ibrutinib. These FDA approved drugs against GC can play a key role in the treatment of COVID-19 patients along with GC as comorbidity. We also hypothesize that JAK, ITK, Rho-associated kinases, FGFR2, FYN, PERK, TYK2, p38-MAPK and SYK kinases can be considered as key therapeutic targets in COVID-19 treatment. Taken altogether, we have proposed the SARS-CoV-2-RdRp as a potential therapeutic target through in-silico studies. However, further in-vitro and in-vivo studies are required for the validation of the proposed targets and drugs for the treatment of COVID-19 patients already suffering from GC.
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Affiliation(s)
- Charu Sonkar
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore, Khandwa Road, Simrol, Indore, 453552, India
| | - Pawan Kumar Doharey
- Department of Biochemistry, University of Allahabad, Allahabad, 211002, U.P., India
| | - Anuranjan Singh Rathore
- SASTRA Deemed to Be University, Trichy-Tanjore Road, Thirumalaisamudram, Thanjavur, Tamil Nadu, 613401, India
| | - Vishal Singh
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Allahabad, 211015, U.P., India
| | - Dharmendra Kashyap
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore, Khandwa Road, Simrol, Indore, 453552, India
| | - Amaresh Kumar Sahoo
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Allahabad, 211015, U.P., India
| | - Nitish Mittal
- Computational and Systems Biology, Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
| | - Bechan Sharma
- Department of Biochemistry, University of Allahabad, Allahabad, 211002, U.P., India
| | - Hem Chandra Jha
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore, Khandwa Road, Simrol, Indore, 453552, India.
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Pitsillou E, Liang J, Yu Meng Huang H, Hung A, Karagiannis TC. In silico investigation to identify potential small molecule inhibitors of the RNA-dependent RNA polymerase (RdRp) nidovirus RdRp-associated nucleotidyltransferase domain. Chem Phys Lett 2021; 779:138889. [PMID: 34305155 PMCID: PMC8273049 DOI: 10.1016/j.cplett.2021.138889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/30/2021] [Accepted: 07/08/2021] [Indexed: 01/18/2023]
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) is a promising target for antiviral drugs. In this study, a chemical library (n = 300) was screened against the nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain. Blind docking was performed using a selection of 30 compounds and nine ligands were chosen based on their docking scores, safety profile, and availability. Using cluster analysis on a 10 microsecond molecular dynamics simulation trajectory (from D.E. Shaw Research), the compounds were docked to the different conformations. On the basis of our modelling studies, oleuropein was identified as a potential lead compound.
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Affiliation(s)
- Eleni Pitsillou
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia,School of Science, STEM College, RMIT University, VIC 3001, Australia
| | - Julia Liang
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia,School of Science, STEM College, RMIT University, VIC 3001, Australia
| | - Helen Yu Meng Huang
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia,Department of Microbiology and Immunology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Andrew Hung
- School of Science, STEM College, RMIT University, VIC 3001, Australia
| | - Tom C. Karagiannis
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia,Department of Clinical Pathology, The University of Melbourne, Parkville, VIC 3052, Australia,Corresponding author
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58
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Dwivedy A, Mariadasse R, Ahmad M, Chakraborty S, Kar D, Tiwari S, Bhattacharyya S, Sonar S, Mani S, Tailor P, Majumdar T, Jeyakanthan J, Biswal BK. Characterization of the NiRAN domain from RNA-dependent RNA polymerase provides insights into a potential therapeutic target against SARS-CoV-2. PLoS Comput Biol 2021; 17:e1009384. [PMID: 34516563 PMCID: PMC8478224 DOI: 10.1371/journal.pcbi.1009384] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 09/28/2021] [Accepted: 08/26/2021] [Indexed: 12/14/2022] Open
Abstract
Apart from the canonical fingers, palm and thumb domains, the RNA dependent RNA polymerases (RdRp) from the viral order Nidovirales possess two additional domains. Of these, the function of the Nidovirus RdRp associated nucleotidyl transferase domain (NiRAN) remains unanswered. The elucidation of the 3D structure of RdRp from the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), provided the first ever insights into the domain organisation and possible functional characteristics of the NiRAN domain. Using in silico tools, we predict that the NiRAN domain assumes a kinase or phosphotransferase like fold and binds nucleoside triphosphates at its proposed active site. Additionally, using molecular docking we have predicted the binding of three widely used kinase inhibitors and five well characterized anti-microbial compounds at the NiRAN domain active site along with their drug-likeliness. For the first time ever, using basic biochemical tools, this study shows the presence of a kinase like activity exhibited by the SARS-CoV-2 RdRp. Interestingly, a well-known kinase inhibitor- Sorafenib showed a significant inhibition and dampened viral load in SARS-CoV-2 infected cells. In line with the current global COVID-19 pandemic urgency and the emergence of newer strains with significantly higher infectivity, this study provides a new anti-SARS-CoV-2 drug target and potential lead compounds for drug repurposing against SARS-CoV-2. The on-going coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is significantly affecting the world health. Unfortunately, over 180 million cases of COVID-19 resulting in nearly 4 million deaths have been reported till June, 2021. In this study, using a combination of bioinformatics, biochemical and mass spectrometry methods, we show that the Nidovirus RdRp associated Nucleotidyl transferase (NiRAN) domain of the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 exhibits a kinase like activity. Additionally, we also show that few broad spectrum anti-cancer and anti-microbial drugs dampen this kinase like activity. Of note, Sorafenib, an FDA approved anti-cancer kinase inhibiting drug significantly reduces the SARS-CoV-2 load in cell lines. Our study suggests that NiRAN domain of the SARS-CoV-2 RdRp is indispensible for the successful viral life cycle and shows that abolishing this enzymatic function of RdRp by small molecule inhibitors may open novel avenues for COVID-19 therapeutics.
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Affiliation(s)
| | | | | | | | | | | | | | - Sudipta Sonar
- Translational Health Science and Technology Institute, Faridabad, India
| | - Shailendra Mani
- Translational Health Science and Technology Institute, Faridabad, India
| | | | - Tanmay Majumdar
- National Institute of Immunology, New Delhi, India
- * E-mail: (TM); (JJ); (BKB)
| | - Jeyaraman Jeyakanthan
- Department of Bioinformatics, Alagappa University, Tamil Nadu, India
- * E-mail: (TM); (JJ); (BKB)
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59
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Dwivedy A, Mariadasse R, Ahmad M, Chakraborty S, Kar D, Tiwari S, Bhattacharyya S, Sonar S, Mani S, Tailor P, Majumdar T, Jeyakanthan J, Biswal BK. Characterization of the NiRAN domain from RNA-dependent RNA polymerase provides insights into a potential therapeutic target against SARS-CoV-2. PLoS Comput Biol 2021. [DOI: https://doi.org/10.1371/journal.pcbi.1009384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apart from the canonical fingers, palm and thumb domains, the RNA dependent RNA polymerases (RdRp) from the viral order Nidovirales possess two additional domains. Of these, the function of the Nidovirus RdRp associated nucleotidyl transferase domain (NiRAN) remains unanswered. The elucidation of the 3D structure of RdRp from the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), provided the first ever insights into the domain organisation and possible functional characteristics of the NiRAN domain. Using in silico tools, we predict that the NiRAN domain assumes a kinase or phosphotransferase like fold and binds nucleoside triphosphates at its proposed active site. Additionally, using molecular docking we have predicted the binding of three widely used kinase inhibitors and five well characterized anti-microbial compounds at the NiRAN domain active site along with their drug-likeliness. For the first time ever, using basic biochemical tools, this study shows the presence of a kinase like activity exhibited by the SARS-CoV-2 RdRp. Interestingly, a well-known kinase inhibitor- Sorafenib showed a significant inhibition and dampened viral load in SARS-CoV-2 infected cells. In line with the current global COVID-19 pandemic urgency and the emergence of newer strains with significantly higher infectivity, this study provides a new anti-SARS-CoV-2 drug target and potential lead compounds for drug repurposing against SARS-CoV-2.
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60
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MacDonald EA, Frey G, Namchuk MN, Harrison SC, Hinshaw SM, Windsor IW. Recognition of Divergent Viral Substrates by the SARS-CoV-2 Main Protease. ACS Infect Dis 2021; 7:2591-2595. [PMID: 34437808 PMCID: PMC8424689 DOI: 10.1021/acsinfecdis.1c00237] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Indexed: 01/01/2023]
Abstract
The main protease (Mpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease (COVID-19), is an ideal target for pharmaceutical inhibition. Mpro is conserved among coronaviruses and distinct from human proteases. Viral replication depends on the cleavage of the viral polyprotein at multiple sites. We present crystal structures of SARS-CoV-2 Mpro bound to two viral substrate peptides. The structures show how Mpro recognizes distinct substrates and how subtle changes in substrate accommodation can drive large changes in catalytic efficiency. One peptide, constituting the junction between viral nonstructural proteins 8 and 9 (nsp8/9), has P1' and P2' residues that are unique among the SARS-CoV-2 Mpro cleavage sites but conserved among homologous junctions in coronaviruses. Mpro cleaves nsp8/9 inefficiently, and amino acid substitutions at P1' or P2' can enhance catalysis. Visualization of Mpro with intact substrates provides new templates for antiviral drug design and suggests that the coronavirus lifecycle selects for finely tuned substrate-dependent catalytic parameters.
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Affiliation(s)
| | - Gary Frey
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
- ICCB-Longwood Screening Facility, Harvard Medical School, Boston, MA, 02115, USA
| | - Mark N. Namchuk
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Stephen C. Harrison
- Laboratory of Molecular Medicine, Boston Children′s Hospital, Boston, MA, 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Stephen M. Hinshaw
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Ian W. Windsor
- Laboratory of Molecular Medicine, Boston Children′s Hospital, Boston, MA, 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, 02139, USA
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61
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Wang B, Svetlov D, Artsimovitch I. NMPylation and de-NMPylation of SARS-CoV-2 nsp9 by the NiRAN domain. Nucleic Acids Res 2021; 49:8822-8835. [PMID: 34352100 PMCID: PMC8385902 DOI: 10.1093/nar/gkab677] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 07/15/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022] Open
Abstract
The catalytic subunit of SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) contains two active sites that catalyze nucleotidyl-monophosphate transfer (NMPylation). Mechanistic studies and drug discovery have focused on RNA synthesis by the highly conserved RdRp. The second active site, which resides in a Nidovirus RdRp-Associated Nucleotidyl transferase (NiRAN) domain, is poorly characterized, but both catalytic reactions are essential for viral replication. One study showed that NiRAN transfers NMP to the first residue of RNA-binding protein nsp9; another reported a structure of nsp9 containing two additional N-terminal residues bound to the NiRAN active site but observed NMP transfer to RNA instead. We show that SARS-CoV-2 RdRp NMPylates the native but not the extended nsp9. Substitutions of the invariant NiRAN residues abolish NMPylation, whereas substitution of a catalytic RdRp Asp residue does not. NMPylation can utilize diverse nucleotide triphosphates, including remdesivir triphosphate, is reversible in the presence of pyrophosphate, and is inhibited by nucleotide analogs and bisphosphonates, suggesting a path for rational design of NiRAN inhibitors. We reconcile these and existing findings using a new model in which nsp9 remodels both active sites to alternately support initiation of RNA synthesis by RdRp or subsequent capping of the product RNA by the NiRAN domain.
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Affiliation(s)
- Bing Wang
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | | | - Irina Artsimovitch
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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62
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Littler DR, Mohanty B, Lowery SA, Colson RN, Gully BS, Perlman S, Scanlon MJ, Rossjohn J. Binding of a pyrimidine RNA base-mimic to SARS-CoV-2 nonstructural protein 9. J Biol Chem 2021; 297:101018. [PMID: 34331944 PMCID: PMC8317483 DOI: 10.1016/j.jbc.2021.101018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 01/18/2023] Open
Abstract
The coronaviral nonstructural protein 9 (Nsp9) is essential for viral replication; it is the primary substrate of Nsp12's pseudokinase domain within the viral replication transcription complex, an association that also recruits other components during different stages of RNA reproduction. In the unmodified state, Nsp9 forms an obligate homodimer via an essential GxxxG protein-interaction motif, but its ssRNA-binding mechanism remains unknown. Using structural biological techniques, here we show that a base-mimicking compound identified from a small molecule fragment screen engages Nsp9 via a tetrameric Pi-Pi stacking interaction that induces the formation of a parallel trimer-of-dimers. This oligomerization mechanism allows an interchange of "latching" N-termini, the charges of which contribute to a series of electropositive channels that suggests a potential interface for viral RNA. The identified pyrrolo-pyrimidine compound may also serve as a potential starting point for the development of compounds seeking to probe Nsp9's role within SARS-CoV-2 replication.
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Affiliation(s)
- Dene R Littler
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
| | - Biswaranjan Mohanty
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; Sydney Analytical Core Research Facility, The University of Sydney, Sydney, New South Wales, Australia; ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Shea A Lowery
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, USA
| | - Rhys N Colson
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Benjamin S Gully
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Stanley Perlman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, USA
| | - Martin J Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
| | - Jamie Rossjohn
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Institute of Infection and Immunity, Cardiff University School of Medicine, Cardiff, United Kingdom.
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Eruera AR, McSweeney AM, McKenzie-Goldsmith GM, Ward VK. Protein Nucleotidylylation in +ssRNA Viruses. Viruses 2021; 13:1549. [PMID: 34452414 PMCID: PMC8402628 DOI: 10.3390/v13081549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 12/22/2022] Open
Abstract
Nucleotidylylation is a post-transcriptional modification important for replication in the picornavirus supergroup of RNA viruses, including members of the Caliciviridae, Coronaviridae, Picornaviridae and Potyviridae virus families. This modification occurs when the RNA-dependent RNA polymerase (RdRp) attaches one or more nucleotides to a target protein through a nucleotidyl-transferase reaction. The most characterized nucleotidylylation target is VPg (viral protein genome-linked), a protein linked to the 5' end of the genome in Caliciviridae, Picornaviridae and Potyviridae. The nucleotidylylation of VPg by RdRp is a critical step for the VPg protein to act as a primer for genome replication and, in Caliciviridae and Potyviridae, for the initiation of translation. In contrast, Coronaviridae do not express a VPg protein, but the nucleotidylylation of proteins involved in replication initiation is critical for genome replication. Furthermore, the RdRp proteins of the viruses that perform nucleotidylylation are themselves nucleotidylylated, and in the case of coronavirus, this has been shown to be essential for viral replication. This review focuses on nucleotidylylation within the picornavirus supergroup of viruses, including the proteins that are modified, what is known about the nucleotidylylation process and the roles that these modifications have in the viral life cycle.
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Affiliation(s)
| | | | | | - Vernon K. Ward
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand; (A.-R.E.); (A.M.M.); (G.M.M.-G.)
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Marjomäki V, Kalander K, Hellman M, Permi P. Enteroviruses and coronaviruses: similarities and therapeutic targets. Expert Opin Ther Targets 2021; 25:479-489. [PMID: 34253126 PMCID: PMC8330013 DOI: 10.1080/14728222.2021.1952985] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Enteroviruses are common viruses causing a huge number of acute and chronic infections and producing towering economic costs. Similarly, coronaviruses cause seasonal mild infections, epidemics, and even pandemics and can lead to severe respiratory symptoms. It is important to develop broadly acting antiviral molecules to efficiently tackle the infections caused by thes.Areas covered: This review illuminates the differences and similarities between enteroviruses and coronaviruses and examines the most appealing therapeutic targets to combat both virus groups. Publications of both virus groups and deposited structures discovered through PubMed to March 2021 for viral proteases have been evaluated.Expert opinion: The main protease of coronaviruses and enteroviruses share similarities in their structure and function. These proteases process their viral polyproteins and thus drugs that bind to the active site have potential to target both virus groups. It is important to develop drugs that target more evolutionarily conserved processes and proteins. Moreover, it is a wise strategy to concentrate on processes that are similar between several virus families.
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Affiliation(s)
- Varpu Marjomäki
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Kerttu Kalander
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Maarit Hellman
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Perttu Permi
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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Tasakis RN, Samaras G, Jamison A, Lee M, Paulus A, Whitehouse G, Verkoczy L, Papavasiliou FN, Diaz M. SARS-CoV-2 variant evolution in the United States: High accumulation of viral mutations over time likely through serial Founder Events and mutational bursts. PLoS One 2021; 16:e0255169. [PMID: 34297786 PMCID: PMC8301627 DOI: 10.1371/journal.pone.0255169] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 07/11/2021] [Indexed: 12/13/2022] Open
Abstract
Since the first case of COVID-19 in December 2019 in Wuhan, China, SARS-CoV-2 has spread worldwide and within a year and a half has caused 3.56 million deaths globally. With dramatically increasing infection numbers, and the arrival of new variants with increased infectivity, tracking the evolution of its genome is crucial for effectively controlling the pandemic and informing vaccine platform development. Our study explores evolution of SARS-CoV-2 in a representative cohort of sequences covering the entire genome in the United States, through all of 2020 and early 2021. Strikingly, we detected many accumulating Single Nucleotide Variations (SNVs) encoding amino acid changes in the SARS-CoV-2 genome, with a pattern indicative of RNA editing enzymes as major mutators of SARS-CoV-2 genomes. We report three major variants through October of 2020. These revealed 14 key mutations that were found in various combinations among 14 distinct predominant signatures. These signatures likely represent evolutionary lineages of SARS-CoV-2 in the U.S. and reveal clues to its evolution such as a mutational burst in the summer of 2020 likely leading to a homegrown new variant, and a trend towards higher mutational load among viral isolates, but with occasional mutation loss. The last quartile of 2020 revealed a concerning accumulation of mostly novel low frequency replacement mutations in the Spike protein, and a hypermutable glutamine residue near the putative furin cleavage site. Finally, end of the year data and 2021 revealed the gradual increase to prevalence of known variants of concern, particularly B.1.1.7, that have acquired additional Spike mutations. Overall, our results suggest that predominant viral genomes are dynamically evolving over time, with periods of mutational bursts and unabated mutation accumulation. This high level of existing variation, even at low frequencies and especially in the Spike-encoding region may become problematic when super-spreader events, akin to serial Founder Events in evolution, drive these rare mutations to prominence.
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Affiliation(s)
- Rafail Nikolaos Tasakis
- Division of Immune Diversity, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Georgios Samaras
- Division of Immune Diversity, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Program of Translational Medical Research, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Anna Jamison
- The Nightingale-Bamford School, New York, NY, United States of America
| | - Michelle Lee
- Cornell University, Ithaca, NY, United States of America
| | - Alexandra Paulus
- The Nightingale-Bamford School, New York, NY, United States of America
| | | | - Laurent Verkoczy
- San Diego Biomedical Research Institute (SDBRI), San Diego, CA, United States of America
| | - F. Nina Papavasiliou
- Division of Immune Diversity, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marilyn Diaz
- San Diego Biomedical Research Institute (SDBRI), San Diego, CA, United States of America
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66
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Brant AC, Tian W, Majerciak V, Yang W, Zheng ZM. SARS-CoV-2: from its discovery to genome structure, transcription, and replication. Cell Biosci 2021; 11:136. [PMID: 34281608 PMCID: PMC8287290 DOI: 10.1186/s13578-021-00643-z] [Citation(s) in RCA: 122] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/30/2021] [Indexed: 02/08/2023] Open
Abstract
SARS-CoV-2 is an extremely contagious respiratory virus causing adult atypical pneumonia COVID-19 with severe acute respiratory syndrome (SARS). SARS-CoV-2 has a single-stranded, positive-sense RNA (+RNA) genome of ~ 29.9 kb and exhibits significant genetic shift from different isolates. After entering the susceptible cells expressing both ACE2 and TMPRSS2, the SARS-CoV-2 genome directly functions as an mRNA to translate two polyproteins from the ORF1a and ORF1b region, which are cleaved by two viral proteases into sixteen non-structural proteins (nsp1-16) to initiate viral genome replication and transcription. The SARS-CoV-2 genome also encodes four structural (S, E, M and N) and up to six accessory (3a, 6, 7a, 7b, 8, and 9b) proteins, but their translation requires newly synthesized individual subgenomic RNAs (sgRNA) in the infected cells. Synthesis of the full-length viral genomic RNA (gRNA) and sgRNAs are conducted inside double-membrane vesicles (DMVs) by the viral replication and transcription complex (RTC), which comprises nsp7, nsp8, nsp9, nsp12, nsp13 and a short RNA primer. To produce sgRNAs, RTC starts RNA synthesis from the highly structured gRNA 3' end and switches template at various transcription regulatory sequence (TRSB) sites along the gRNA body probably mediated by a long-distance RNA-RNA interaction. The TRS motif in the gRNA 5' leader (TRSL) is responsible for the RNA-RNA interaction with the TRSB upstream of each ORF and skipping of the viral genome in between them to produce individual sgRNAs. Abundance of individual sgRNAs and viral gRNA synthesized in the infected cells depend on the location and read-through efficiency of each TRSB. Although more studies are needed, the unprecedented COVID-19 pandemic has taught the world a painful lesson that is to invest and proactively prepare future emergence of other types of coronaviruses and any other possible biological horrors.
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Affiliation(s)
- Ayslan Castro Brant
- Tumor Virus RNA Biology Section, HIV DRP, National Cancer Institute, NIH, Frederick, MD, USA
| | - Wei Tian
- Mechanism of DNA Repair, Replication, and Recombination Section, Laboratory of Molecular Biology, NIDDK, Bethesda, MD, USA
| | - Vladimir Majerciak
- Tumor Virus RNA Biology Section, HIV DRP, National Cancer Institute, NIH, Frederick, MD, USA
| | - Wei Yang
- Mechanism of DNA Repair, Replication, and Recombination Section, Laboratory of Molecular Biology, NIDDK, Bethesda, MD, USA.
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, HIV DRP, National Cancer Institute, NIH, Frederick, MD, USA.
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67
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Yan L, Yang Y, Li M, Zhang Y, Zheng L, Ge J, Huang YC, Liu Z, Wang T, Gao S, Zhang R, Huang YY, Guddat LW, Gao Y, Rao Z, Lou Z. Coupling of N7-methyltransferase and 3'-5' exoribonuclease with SARS-CoV-2 polymerase reveals mechanisms for capping and proofreading. Cell 2021; 184:3474-3485.e11. [PMID: 34143953 PMCID: PMC8142856 DOI: 10.1016/j.cell.2021.05.033] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/20/2021] [Accepted: 05/19/2021] [Indexed: 12/16/2022]
Abstract
The capping of mRNA and the proofreading play essential roles in SARS-CoV-2 replication and transcription. Here, we present the cryo-EM structure of the SARS-CoV-2 replication-transcription complex (RTC) in a form identified as Cap(0)-RTC, which couples a co-transcriptional capping complex (CCC) composed of nsp12 NiRAN, nsp9, the bifunctional nsp14 possessing an N-terminal exoribonuclease (ExoN) and a C-terminal N7-methyltransferase (N7-MTase), and nsp10 as a cofactor of nsp14. Nsp9 and nsp12 NiRAN recruit nsp10/nsp14 into the Cap(0)-RTC, forming the N7-CCC to yield cap(0) (7MeGpppA) at 5' end of pre-mRNA. A dimeric form of Cap(0)-RTC observed by cryo-EM suggests an in trans backtracking mechanism for nsp14 ExoN to facilitate proofreading of the RNA in concert with polymerase nsp12. These results not only provide a structural basis for understanding co-transcriptional modification of SARS-CoV-2 mRNA but also shed light on how replication fidelity in SARS-CoV-2 is maintained.
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Affiliation(s)
- Liming Yan
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yunxiang Yang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Mingyu Li
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Ying Zhang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Litao Zheng
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China; School of Life Sciences, Tsinghua University, Beijing, China
| | - Ji Ge
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yucen C Huang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Zhenyu Liu
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Tao Wang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shan Gao
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Ran Zhang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuanyun Y Huang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Luke W Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Yan Gao
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
| | - Zihe Rao
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China; School of Life Sciences, Tsinghua University, Beijing, China; State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences and College of Pharmacy, Nankai University, Tianjin, China; National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; Guangzhou Laboratory, Guangzhou, China.
| | - Zhiyong Lou
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Guangzhou Laboratory, Guangzhou, China.
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Allosteric Activation of SARS-CoV-2 RNA-Dependent RNA Polymerase by Remdesivir Triphosphate and Other Phosphorylated Nucleotides. mBio 2021; 12:e0142321. [PMID: 34154407 PMCID: PMC8262916 DOI: 10.1128/mbio.01423-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The catalytic subunit of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) Nsp12 has a unique nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain that transfers nucleoside monophosphates to the Nsp9 protein and the nascent RNA. The NiRAN and RdRp modules form a dynamic interface distant from their catalytic sites, and both activities are essential for viral replication. We report that codon-optimized (for the pause-free translation in bacterial cells) Nsp12 exists in an inactive state in which NiRAN-RdRp interactions are broken, whereas translation by slow ribosomes and incubation with accessory Nsp7/8 subunits or nucleoside triphosphates (NTPs) partially rescue RdRp activity. Our data show that adenosine and remdesivir triphosphates promote the synthesis of A-less RNAs, as does ppGpp, while amino acid substitutions at the NiRAN-RdRp interface augment activation, suggesting that ligand binding to the NiRAN catalytic site modulates RdRp activity. The existence of allosterically linked nucleotidyl transferase sites that utilize the same substrates has important implications for understanding the mechanism of SARS-CoV-2 replication and the design of its inhibitors.
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69
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Luo R, Delaunay‐Moisan A, Timmis K, Danchin A. SARS-CoV-2 biology and variants: anticipation of viral evolution and what needs to be done. Environ Microbiol 2021; 23:2339-2363. [PMID: 33769683 PMCID: PMC8251359 DOI: 10.1111/1462-2920.15487] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022]
Abstract
The global propagation of SARS-CoV-2 and the detection of a large number of variants, some of which have replaced the original clade to become dominant, underscores the fact that the virus is actively exploring its evolutionary space. The longer high levels of viral multiplication occur - permitted by high levels of transmission -, the more the virus can adapt to the human host and find ways to success. The third wave of the COVID-19 pandemic is starting in different parts of the world, emphasizing that transmission containment measures that are being imposed are not adequate. Part of the consideration in determining containment measures is the rationale that vaccination will soon stop transmission and allow a return to normality. However, vaccines themselves represent a selection pressure for evolution of vaccine-resistant variants, so the coupling of a policy of permitting high levels of transmission/virus multiplication during vaccine roll-out with the expectation that vaccines will deal with the pandemic, is unrealistic. In the absence of effective antivirals, it is not improbable that SARS-CoV-2 infection prophylaxis will involve an annual vaccination campaign against 'dominant' viral variants, similar to influenza prophylaxis. Living with COVID-19 will be an issue of SARS-CoV-2 variants and evolution. It is therefore crucial to understand how SARS-CoV-2 evolves and what constrains its evolution, in order to anticipate the variants that will emerge. Thus far, the focus has been on the receptor-binding spike protein, but the virus is complex, encoding 26 proteins which interact with a large number of host factors, so the possibilities for evolution are manifold and not predictable a priori. However, if we are to mount the best defence against COVID-19, we must mount it against the variants, and to do this, we must have knowledge about the evolutionary possibilities of the virus. In addition to the generic cellular interactions of the virus, there are extensive polymorphisms in humans (e.g. Lewis, HLA, etc.), some distributed within most or all populations, some restricted to specific ethnic populations and these variations pose additional opportunities for/constraints on viral evolution. We now have the wherewithal - viral genome sequencing, protein structure determination/modelling, protein interaction analysis - to functionally characterize viral variants, but access to comprehensive genome data is extremely uneven. Yet, to develop an understanding of the impacts of such evolution on transmission and disease, we must link it to transmission (viral epidemiology) and disease data (patient clinical data), and the population granularities of these. In this editorial, we explore key facets of viral biology and the influence of relevant aspects of human polymorphisms, human behaviour, geography and climate and, based on this, derive a series of recommendations to monitor viral evolution and predict the types of variants that are likely to arise.
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Affiliation(s)
- Ruibang Luo
- Department of Computer ScienceThe University of Hong KongBonham RoadPokfulamHong Kong
| | - Agnès Delaunay‐Moisan
- Université Paris‐Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Gif‐sur‐Yvette91198France
| | - Kenneth Timmis
- Institute of MicrobiologyTechnical University of BraunschweigBraunschweigGermany
| | - Antoine Danchin
- Kodikos Labs, Institut Cochin, 24 rue du Faubourg Saint‐JacquesParis75014France
- School of Biomedical Sciences, Li Kashing Faculty of MedicineUniversity of Hong Kong21 Sassoon RoadHong Kong
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70
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Wang B, Svetlov V, Wolf YI, Koonin EV, Nudler E, Artsimovitch I. Allosteric activation of SARS-CoV-2 RdRp by remdesivir triphosphate and other phosphorylated nucleotides. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.01.24.428004. [PMID: 33948598 PMCID: PMC8095223 DOI: 10.1101/2021.01.24.428004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The catalytic subunit of SARS-CoV-2 RNA-dependent RNA polymerase (RdRp), Nsp12, has a unique NiRAN domain that transfers nucleoside monophosphates to the Nsp9 protein. The NiRAN and RdRp modules form a dynamic interface distant from their catalytic sites and both activities are essential for viral replication. We report that codon-optimized (for the pause-free translation) Nsp12 exists in inactive state in which NiRAN/RdRp interactions are broken, whereas translation by slow ribosomes and incubation with accessory Nsp7/8 subunits or NTPs partially rescue RdRp activity. Our data show that adenosine and remdesivir triphosphates promote synthesis of A-less RNAs, as does ppGpp, while amino acid substitutions at the NiRAN/RdRp interface augment activation, suggesting that ligand binding to the NiRAN catalytic site modulates RdRp activity. The existence of allosterically-linked nucleotidyl transferase sites that utilize the same substrates has important implications for understanding the mechanism of SARS-CoV-2 replication and design of its inhibitors. HIGHLIGHTS Codon-optimization of Nsp12 triggers misfolding and activity lossSlow translation, accessory Nsp7 and Nsp8 subunits, and NTPs rescue Nsp12Non-substrate nucleotides activate RNA chain synthesis, likely via NiRAN domainCrosstalk between two Nsp12 active sites that bind the same ligands.
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Affiliation(s)
- Bing Wang
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Vladimir Svetlov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Irina Artsimovitch
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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Hillen HS. Structure and function of SARS-CoV-2 polymerase. Curr Opin Virol 2021; 48:82-90. [PMID: 33945951 PMCID: PMC8023233 DOI: 10.1016/j.coviro.2021.03.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/18/2021] [Accepted: 03/30/2021] [Indexed: 01/18/2023]
Abstract
Coronaviruses use an RNA-dependent RNA polymerase (RdRp) to replicate and express their genome. The RdRp associates with additional non-structural proteins (nsps) to form a replication–transcription complex (RTC) that carries out RNA synthesis, capping and proofreading. However, the structure of the RdRp long remained elusive, thus limiting our understanding of coronavirus genome expression and replication. Recently, the cryo-electron microscopy structure of SARS-CoV-1 RdRp was reported. Driven by the ongoing COVID-19 pandemic, structural data on the SARS-CoV-2 polymerase and associated factors has since emerged at an unprecedented pace, with more than twenty structures released to date. This review provides an overview of the currently available coronavirus RdRp structures and outlines how they have, together with functional studies, led to a molecular understanding of the viral polymerase, its interactions with accessory factors and the mechanisms by which promising antivirals may inhibit coronavirus replication.
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Affiliation(s)
- Hauke S Hillen
- Department of Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; Research Group Structure and Function of Molecular Machines, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, D-37075 Göttingen, Germany.
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Yoo JH. What We Do Know and Do Not Yet Know about COVID-19 Vaccines as of the Beginning of the Year 2021. J Korean Med Sci 2021; 36:e54. [PMID: 33559409 PMCID: PMC7870421 DOI: 10.3346/jkms.2021.36.e54] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 12/12/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19), which started at the end of 2019 and has spread worldwide, has remained unabated in 2021. Since non-pharmaceutical interventions including social distancing are facing limitations in controlling COVID-19, additional absolute means to change the trend are necessary. To this end, coronavirus-specific antiviral drugs and vaccines are urgently needed, but for now, the priority is to promote herd immunity through extensive nationwide vaccination campaign. In addition to the vaccines based on the conventional technology such inactivated or killed virus or protein subunit vaccines, several vaccines on the new technological platforms, for example, nucleic acids-based vaccines delivered by viral carriers, nanoparticles, or plasmids as a medium were introduced in this pandemic. In addition to achieving sufficient herd immunity with vaccination, the development of antiviral treatments that work specifically against COVID-19 will also be necessary to terminate the epidemic completely.
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Affiliation(s)
- Jin Hong Yoo
- Division of Infectious Diseases, Department of Internal Medicine, Bucheon St. Mary's Hospital, Bucheon, Korea
- Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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