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Danda M, Klimešová A, Kušková K, Dostálková A, Pagáčová A, Prchal J, Kapisheva M, Ruml T, Rumlová M. Biochemical characterization of naturally occurring mutations in SARS-CoV-2 RNA-dependent RNA polymerase. Protein Sci 2024; 33:e5103. [PMID: 39145418 PMCID: PMC11325161 DOI: 10.1002/pro.5103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 06/06/2024] [Accepted: 06/21/2024] [Indexed: 08/16/2024]
Abstract
Since the emergence of SARS-CoV-2, mutations in all subunits of the RNA-dependent RNA polymerase (RdRp) of the virus have been repeatedly reported. Although RdRp represents a primary target for antiviral drugs, experimental studies exploring the phenotypic effect of these mutations have been limited. This study focuses on the phenotypic effects of substitutions in the three RdRp subunits: nsp7, nsp8, and nsp12, selected based on their occurrence rate and potential impact. We employed nano-differential scanning fluorimetry and microscale thermophoresis to examine the impact of these mutations on protein stability and RdRp complex assembly. We observed diverse impacts; notably, a single mutation in nsp8 significantly increased its stability as evidenced by a 13°C increase in melting temperature, whereas certain mutations in nsp7 and nsp8 reduced their binding affinity to nsp12 during RdRp complex formation. Using a fluorometric enzymatic assay, we assessed the overall effect on RNA polymerase activity. We found that most of the examined mutations altered the polymerase activity, often as a direct result of changes in stability or affinity to the other components of the RdRp complex. Intriguingly, a combination of nsp8 A21V and nsp12 P323L mutations resulted in a 50% increase in polymerase activity. To our knowledge, this is the first biochemical study to demonstrate the impact of amino acid mutations across all components constituting the RdRp complex in emerging SARS-CoV-2 subvariants.
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Affiliation(s)
- Matěj Danda
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Anna Klimešová
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Klára Kušková
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Alžběta Dostálková
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Aneta Pagáčová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - Jan Prchal
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - Marina Kapisheva
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - Michaela Rumlová
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
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2
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Naidu AS, Wang CK, Rao P, Mancini F, Clemens RA, Wirakartakusumah A, Chiu HF, Yen CH, Porretta S, Mathai I, Naidu SAG. Precision nutrition to reset virus-induced human metabolic reprogramming and dysregulation (HMRD) in long-COVID. NPJ Sci Food 2024; 8:19. [PMID: 38555403 PMCID: PMC10981760 DOI: 10.1038/s41538-024-00261-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 03/15/2024] [Indexed: 04/02/2024] Open
Abstract
SARS-CoV-2, the etiological agent of COVID-19, is devoid of any metabolic capacity; therefore, it is critical for the viral pathogen to hijack host cellular metabolic machinery for its replication and propagation. This single-stranded RNA virus with a 29.9 kb genome encodes 14 open reading frames (ORFs) and initiates a plethora of virus-host protein-protein interactions in the human body. These extensive viral protein interactions with host-specific cellular targets could trigger severe human metabolic reprogramming/dysregulation (HMRD), a rewiring of sugar-, amino acid-, lipid-, and nucleotide-metabolism(s), as well as altered or impaired bioenergetics, immune dysfunction, and redox imbalance in the body. In the infectious process, the viral pathogen hijacks two major human receptors, angiotensin-converting enzyme (ACE)-2 and/or neuropilin (NRP)-1, for initial adhesion to cell surface; then utilizes two major host proteases, TMPRSS2 and/or furin, to gain cellular entry; and finally employs an endosomal enzyme, cathepsin L (CTSL) for fusogenic release of its viral genome. The virus-induced HMRD results in 5 possible infectious outcomes: asymptomatic, mild, moderate, severe to fatal episodes; while the symptomatic acute COVID-19 condition could manifest into 3 clinical phases: (i) hypoxia and hypoxemia (Warburg effect), (ii) hyperferritinemia ('cytokine storm'), and (iii) thrombocytosis (coagulopathy). The mean incubation period for COVID-19 onset was estimated to be 5.1 days, and most cases develop symptoms after 14 days. The mean viral clearance times were 24, 30, and 39 days for acute, severe, and ICU-admitted COVID-19 patients, respectively. However, about 25-70% of virus-free COVID-19 survivors continue to sustain virus-induced HMRD and exhibit a wide range of symptoms that are persistent, exacerbated, or new 'onset' clinical incidents, collectively termed as post-acute sequelae of COVID-19 (PASC) or long COVID. PASC patients experience several debilitating clinical condition(s) with >200 different and overlapping symptoms that may last for weeks to months. Chronic PASC is a cumulative outcome of at least 10 different HMRD-related pathophysiological mechanisms involving both virus-derived virulence factors and a multitude of innate host responses. Based on HMRD and virus-free clinical impairments of different human organs/systems, PASC patients can be categorized into 4 different clusters or sub-phenotypes: sub-phenotype-1 (33.8%) with cardiac and renal manifestations; sub-phenotype-2 (32.8%) with respiratory, sleep and anxiety disorders; sub-phenotype-3 (23.4%) with skeleto-muscular and nervous disorders; and sub-phenotype-4 (10.1%) with digestive and pulmonary dysfunctions. This narrative review elucidates the effects of viral hijack on host cellular machinery during SARS-CoV-2 infection, ensuing detrimental effect(s) of virus-induced HMRD on human metabolism, consequential symptomatic clinical implications, and damage to multiple organ systems; as well as chronic pathophysiological sequelae in virus-free PASC patients. We have also provided a few evidence-based, human randomized controlled trial (RCT)-tested, precision nutrients to reset HMRD for health recovery of PASC patients.
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Affiliation(s)
- A Satyanarayan Naidu
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA.
- N-terminus Research Laboratory, 232659 Via del Rio, Yorba Linda, CA, 92887, USA.
| | - Chin-Kun Wang
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA
- School of Nutrition, Chung Shan Medical University, 110, Section 1, Jianguo North Road, Taichung, 40201, Taiwan
| | - Pingfan Rao
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA
- College of Food and Bioengineering, Fujian Polytechnic Normal University, No.1, Campus New Village, Longjiang Street, Fuqing City, Fujian, China
| | - Fabrizio Mancini
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA
- President-Emeritus, Parker University, 2540 Walnut Hill Lane, Dallas, TX, 75229, USA
| | - Roger A Clemens
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA
- University of Southern California, Alfred E. Mann School of Pharmacy/D. K. Kim International Center for Regulatory & Quality Sciences, 1540 Alcazar St., CHP 140, Los Angeles, CA, 90089, USA
| | - Aman Wirakartakusumah
- International Union of Food Science and Technology (IUFoST), Guelph, ON, Canada
- IPMI International Business School Jakarta; South East Asian Food and Agriculture Science and Technology, IPB University, Bogor, Indonesia
| | - Hui-Fang Chiu
- Department of Chinese Medicine, Taichung Hospital, Ministry of Health & Well-being, Taichung, Taiwan
| | - Chi-Hua Yen
- Department of Family and Community Medicine, Chung Shan Medical University Hospital; School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Sebastiano Porretta
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA
- President, Italian Association of Food Technology (AITA), Milan, Italy
- Experimental Station for the Food Preserving Industry, Department of Consumer Science, Viale Tanara 31/a, I-43121, Parma, Italy
| | - Issac Mathai
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA
- Soukya International Holistic Health Center, Whitefield, Bengaluru, India
| | - Sreus A G Naidu
- Global Nutrition Healthcare Council (GNHC) Mission-COVID, Yorba Linda, CA, USA
- N-terminus Research Laboratory, 232659 Via del Rio, Yorba Linda, CA, 92887, USA
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3
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Paredes-Amaya CC, Ulloa MT, García-Angulo VA. Fierce poison to others: the phenomenon of bacterial dependence on antibiotics. J Biomed Sci 2023; 30:67. [PMID: 37574554 PMCID: PMC10424368 DOI: 10.1186/s12929-023-00963-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023] Open
Abstract
Beyond the development of resistance, the effects of antibiotics on bacteria and microbial communities are complex and far from exhaustively studied. In the context of the current global antimicrobial resistance crisis, understanding the adaptive and physiological responses of bacteria to antimicrobials is of paramount importance along with the development of new therapies. Bacterial dependence on antibiotics is a phenomenon in which antimicrobials instead of eliminating the pathogens actually provide a boost for their growth. This trait comprises an extreme example of the complexities of responses elicited by microorganisms to these drugs. This compelling evolutionary trait was readily described along with the first wave of antibiotics use and dependence to various antimicrobials has been reported. Nevertheless, current molecular characterizations have been focused on dependence on vancomycin, linezolid and colistin, three critically important antibiotics frequently used as last resource therapy for multi resistant pathogens. Outstanding advances have been made in understanding the molecular basis for the dependence to vancomycin, including specific mutations involved. Regarding linezolid and colistin, the general physiological components affected by the dependence, namely ribosomes and membrane function respectively, have been established. Nonetheless the implications of antibiotic dependence in clinically relevant features, such as virulence, epidemics, relationship with development of resistance, diagnostics and therapy effectiveness require clarification. This review presents a brief introduction of the phenomenon of bacterial dependence to antibiotics and a summary on early and current research concerning the basis for this trait. Furthermore, the available information on the effect of dependence in key clinical aspects is discussed. The studies performed so far underline the need to fully disclose the biological and clinical significance of this trait in pathogens to successfully assess its role in resistance and to design adjusted therapies.
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Affiliation(s)
- Claudia C Paredes-Amaya
- Microbiology Department, Escuela de Ciencias Básicas, Facultad de Salud, Universidad del Valle, Cali, Colombia
| | - María Teresa Ulloa
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile
- Vertebral I+D+i - Corporation for Assistance for Burned Children (Coaniquem), Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile.
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4
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Yan D, Yan B. Viral target and metabolism-based rationale for combined use of recently authorized small molecule COVID-19 medicines: Molnupiravir, nirmatrelvir, and remdesivir. Fundam Clin Pharmacol 2023; 37:726-738. [PMID: 36931725 PMCID: PMC10505250 DOI: 10.1111/fcp.12889] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/12/2023] [Accepted: 02/27/2023] [Indexed: 03/19/2023]
Abstract
The COVID-19 pandemic remains a major health concern worldwide, and SARS-CoV-2 is continuously evolving. There is an urgent need to identify new antiviral drugs and develop novel therapeutic strategies. Combined use of newly authorized COVID-19 medicines including molnupiravir, nirmatrelvir, and remdesivir has been actively pursued. Mechanistically, nirmatrelvir inhibits SARS-CoV-2 replication by targeting the viral main protease (Mpro ), a critical enzyme in the processing of the immediately translated coronavirus polyproteins for viral replication. Molnupiravir and remdesivir, on the other hand, inhibit SARS-CoV-2 replication by targeting RNA-dependent RNA-polymerase (RdRp), which is directly responsible for genome replication and production of subgenomic RNAs. Molnupiravir targets RdRp and induces severe viral RNA mutations (genome), commonly referred to as error catastrophe. Remdesivir, in contrast, targets RdRp and causes chain termination and arrests RNA synthesis of the viral genome. In addition, all three medicines undergo extensive metabolism with strong therapeutic significance. Molnupiravir is hydrolytically activated by carboxylesterase-2 (CES2), nirmatrelvir is inactivated by cytochrome P450-based oxidation (e.g., CYP3A4), and remdesivir is hydrolytically activated by CES1 but covalently inhibits CES2. Additionally, remdesivir and nirmatrelvir are oxidized by the same CYP enzymes. The distinct mechanisms of action provide strong rationale for their combined use. On the other hand, these drugs undergo extensive metabolism that determines their therapeutic potential. This review discusses how metabolism pathways and enzymes involved should be carefully considered during their combined use for therapeutic synergy.
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Affiliation(s)
- Daisy Yan
- Department of Dermatology, Boston University School of Medicine 609 Albany Street Boston, MA 02118
| | - Bingfang Yan
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH 45229
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5
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Majdalani N, Chattopadhyay M, Keller C, Gottesman S. Lack of polyamines leads to cotranslational degradation of the general stress factor RpoS in Escherichia coli. J Biol Chem 2023; 299:104943. [PMID: 37343699 PMCID: PMC10372455 DOI: 10.1016/j.jbc.2023.104943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
The specialized sigma factor RpoS mediates a general stress response in Escherichia coli and related bacteria, activating promoters that allow cells to survive stationary phase and many stresses. RpoS synthesis and stability are regulated at multiple levels. Translation of RpoS is positively regulated by multiple small RNAs in response to stress. Degradation of RpoS, dependent upon the adaptor protein RssB, is rapid during exponential growth and ceases upon starvation or other stresses, increasing accumulation of RpoS. E. coli carrying mutations that block the synthesis of polyamines were previously found to have low levels of RpoS, while levels increased rapidly when polyamines were added. We have used a series of reporters to examine the basis for the lack of RpoS in polyamine-deficient cells. The polyamine requirement was independent of small RNA-mediated positive regulation of RpoS translation. Mutations in rssB stabilize RpoS and significantly bypassed the polyamine deficit, suggesting that lack of polyamines might lead to rapid RpoS degradation. However, rates of degradation of mature RpoS were unaffected by polyamine availability. Codon optimization in rpoS partially relieved the polyamine dependence, suggesting a defect in RpoS translation in the absence of polyamines. Consistent with this, a hyperproofreading allele of ribosomal protein S12, encoded by rpsL, showed a decrease in RpoS levels, and this decrease was also suppressed by either codon optimization or blocking RpoS degradation. We suggest that rpoS codon usage leads it to be particularly sensitive to slowed translation, due to either lack of polyamines or hyperproofreading, leading to cotranslational degradation. We dedicate this study to Herb Tabor and his foundational work on polyamines, including the basis for this study.
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Affiliation(s)
- Nadim Majdalani
- Laboratory of Molecular Biology, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | - Manas Chattopadhyay
- Laboratory of Biochemistry and Genetics, NIDDK, NIH, Bethesda, Maryland, USA
| | - Christopher Keller
- Laboratory of Biochemistry and Genetics, NIDDK, NIH, Bethesda, Maryland, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, NCI, Bethesda, Maryland, USA.
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6
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Petushkov I, Esyunina D, Kulbachinskiy A. Effects of natural RNA modifications on the activity of SARS-CoV-2 RNA-dependent RNA polymerase. FEBS J 2023; 290:80-92. [PMID: 35916766 PMCID: PMC9538676 DOI: 10.1111/febs.16587] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/17/2022] [Accepted: 08/01/2022] [Indexed: 01/18/2023]
Abstract
RNA-dependent RNA polymerase (RdRp) plays a key role in the replication of RNA viruses, including SARS-CoV-2. Processive RNA synthesis by RdRp is crucial for successful genome replication and expression, especially in the case of very long coronaviral genomes. Here, we analysed the activity of SARS-CoV-2 RdRp (the nsp12-nsp7-nsp8 complex) on synthetic primer-templates of various structures, including substrates with mismatched primers or template RNA modifications. It has been shown that RdRp cannot efficiently extend RNA primers containing mismatches and has no intrinsic RNA cleavage activity to remove the primer 3'-end, thus necessitating the action of exoribonuclease for proofreading. Similar to DNA-dependent RNA polymerases, RdRp can perform processive pyrophosphorolysis of the nascent RNA product but this reaction is also blocked in the presence of mismatches. Furthermore, we have demonstrated that several natural post-transcriptional modifications in the RNA template, which do not prevent complementary interactions (N6-methyladenosine, 5-methylcytosine, inosine and pseudouridine), do not change RdRp processivity. At the same time, certain modifications of RNA bases and ribose residues strongly block RNA synthesis, either prior to nucleotide incorporation (3-methyluridine and 1-methylguanosine) or immediately after it (2'-O-methylation). The results demonstrate that the activity of SARS-CoV-2 RdRp can be strongly inhibited by common modifications of the RNA template suggesting a way to design novel antiviral compounds.
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Affiliation(s)
- Ivan Petushkov
- Institute of Molecular Genetics, National Research Center “Kurchatov Institute”MoscowRussia
| | - Daria Esyunina
- Institute of Molecular Genetics, National Research Center “Kurchatov Institute”MoscowRussia
| | - Andrey Kulbachinskiy
- Institute of Molecular Genetics, National Research Center “Kurchatov Institute”MoscowRussia
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7
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Gao S, Song L, Xu H, Fikatas A, Oeyen M, De Jonghe S, Zhao F, Jing L, Jochmans D, Vangeel L, Cheng Y, Kang D, Neyts J, Herdewijn P, Schols D, Zhan P, Liu X. Identification of Polyphenol Derivatives as Novel SARS-CoV-2 and DENV Non-Nucleoside RdRp Inhibitors. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010160. [PMID: 36615354 PMCID: PMC9822497 DOI: 10.3390/molecules28010160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022]
Abstract
The Coronavirus Disease 2019 (COVID-19) and dengue fever (DF) pandemics both remain to be significant public health concerns in the foreseeable future. Anti-SARS-CoV-2 drugs and vaccines are both indispensable to eliminate the epidemic situation. Here, two piperazine-based polyphenol derivatives DF-47 and DF-51 were identified as potential inhibitors directly blocking the active site of SARS-CoV-2 and DENV RdRp. Data through RdRp inhibition screening of an in-house library and in vitro antiviral study selected DF-47 and DF-51 as effective inhibitors of SARS-CoV-2/DENV polymerase. Moreover, in silico simulation revealed stable binding modes between the DF-47/DF-51 and SARS-CoV-2/DENV RdRp, respectively, including chelating with Mg2+ near polymerase active site. This work discovered the inhibitory effect of two polyphenols on distinct viral RdRp, which are expected to be developed into broad-spectrum, non-nucleoside RdRp inhibitors with new scaffold.
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Affiliation(s)
- Shenghua Gao
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Shenzhen Research Institute of Shandong University, A301 Virtual University Park in South District of Shenzhen, Shenzhen 518057, China
| | - Letian Song
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Hongtao Xu
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
- Correspondence: (H.X.); (D.S.); (P.Z.); (X.L.)
| | - Antonios Fikatas
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Merel Oeyen
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Steven De Jonghe
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Fabao Zhao
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Lanlan Jing
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Dirk Jochmans
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Laura Vangeel
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Yusen Cheng
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Dongwei Kang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Johan Neyts
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Piet Herdewijn
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, 3000 Leuven, Belgium
| | - Dominique Schols
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
- Correspondence: (H.X.); (D.S.); (P.Z.); (X.L.)
| | - Peng Zhan
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Correspondence: (H.X.); (D.S.); (P.Z.); (X.L.)
| | - Xinyong Liu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Department of Pharmacology, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- Correspondence: (H.X.); (D.S.); (P.Z.); (X.L.)
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8
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Ghosh AK, Mishevich JL, Mesecar A, Mitsuya H. Recent Drug Development and Medicinal Chemistry Approaches for the Treatment of SARS-CoV-2 Infection and COVID-19. ChemMedChem 2022; 17:e202200440. [PMID: 36165855 PMCID: PMC9538661 DOI: 10.1002/cmdc.202200440] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/21/2022] [Indexed: 01/14/2023]
Abstract
COVID-19, caused by SARS-CoV-2 infection, continues to be a major public health crisis around the globe. Development of vaccines and the first cluster of antiviral drugs has brought promise and hope for prevention and treatment of severe coronavirus disease. However, continued development of newer, safer, and more effective antiviral drugs are critically important to combat COVID-19 and counter the looming pathogenic variants. Studies of the coronavirus life cycle revealed several important biochemical targets for drug development. In the present review, we focus on recent drug design and medicinal chemistry efforts in small molecule drug discovery, including the development of nirmatrelvir that targets viral protein synthesis and remdesivir and molnupiravir that target viral RdRp. These are recent FDA approved drugs for the treatment of COVID-19.
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Affiliation(s)
- Arun K Ghosh
- Purdue UniversityDepartments of Chemistry and Medicinal Chemistry560 Oval Drive47907West LafayetteUNITED STATES
| | | | - Andrew Mesecar
- Purdue University College of ScienceBiochemistryUNITED STATES
| | - Hiroaki Mitsuya
- National Cancer InstituteHIV and AIDS Malignancy BranchUNITED STATES
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9
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Wang T, Cao Y, Zhang H, Wang Z, Man CH, Yang Y, Chen L, Xu S, Yan X, Zheng Q, Wang Y. COVID-19 metabolism: Mechanisms and therapeutic targets. MedComm (Beijing) 2022; 3:e157. [PMID: 35958432 PMCID: PMC9363584 DOI: 10.1002/mco2.157] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 01/18/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dysregulates antiviral signaling, immune response, and cell metabolism in human body. Viral genome and proteins hijack host metabolic network to support viral biogenesis and propagation. However, the regulatory mechanism of SARS-CoV-2-induced metabolic dysfunction has not been elucidated until recently. Multiomic studies of coronavirus disease 2019 (COVID-19) revealed an intensive interaction between host metabolic regulators and viral proteins. SARS-CoV-2 deregulated cellular metabolism in blood, intestine, liver, pancreas, fat, and immune cells. Host metabolism supported almost every stage of viral lifecycle. Strikingly, viral proteins were found to interact with metabolic enzymes in different cellular compartments. Biochemical and genetic assays also identified key regulatory nodes and metabolic dependencies of viral replication. Of note, cholesterol metabolism, lipid metabolism, and glucose metabolism are broadly involved in viral lifecycle. Here, we summarized the current understanding of the hallmarks of COVID-19 metabolism. SARS-CoV-2 infection remodels host cell metabolism, which in turn modulates viral biogenesis and replication. Remodeling of host metabolism creates metabolic vulnerability of SARS-CoV-2 replication, which could be explored to uncover new therapeutic targets. The efficacy of metabolic inhibitors against COVID-19 is under investigation in several clinical trials. Ultimately, the knowledge of SARS-CoV-2-induced metabolic reprogramming would accelerate drug repurposing or screening to combat the COVID-19 pandemic.
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Affiliation(s)
- Tianshi Wang
- Shanghai Key Laboratory for Tumor Microenvironment and InflammationDepartment of Biochemistry and Molecular Cell BiologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Ying Cao
- State Key Laboratory of Oncogenes and Related GenesShanghai Cancer InstituteRenji HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Haiyan Zhang
- Bai Jia Obstetrics and Gynecology HospitalShanghaiChina
| | - Zihao Wang
- Fudan University Shanghai Cancer CenterKey Laboratory of Breast Cancer in ShanghaiShanghai Key Laboratory of Radiation OncologyCancer Instituteand The Shanghai Key Laboratory of Medical EpigeneticsInstitutes of Biomedical SciencesShanghai Medical CollegeFudan UniversityShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- The International Co‐laboratory of Medical Epigenetics and MetabolismMinistry of Science and TechnologyShanghaiChina
| | - Cheuk Him Man
- Division of HematologyDepartment of MedicineUniversity of Hong KongPokfulamHong Kong, China
| | - Yunfan Yang
- Department of Cell BiologySchool of Basic Medical SciencesCheeloo College of MedicineShandong UniversityJinanChina
| | - Lingchao Chen
- Department of NeurosurgeryHuashan HospitalShanghai Medical CollegeFudan UniversityNational Center for Neurological DisordersShanghai Key Laboratory of Brain Function and Restoration and Neural RegenerationNeurosurgical Institute of Fudan UniversityShanghai Clinical Medical Center of NeurosurgeryShanghaiChina
| | - Shuangnian Xu
- Department of HematologySouthwest HospitalArmy Medical UniversityChongqingChina
| | - Xiaojing Yan
- Department of HematologyThe First Affiliated Hospital of China Medical UniversityShenyangChina
| | - Quan Zheng
- Center for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yi‐Ping Wang
- Fudan University Shanghai Cancer CenterKey Laboratory of Breast Cancer in ShanghaiShanghai Key Laboratory of Radiation OncologyCancer Instituteand The Shanghai Key Laboratory of Medical EpigeneticsInstitutes of Biomedical SciencesShanghai Medical CollegeFudan UniversityShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- The International Co‐laboratory of Medical Epigenetics and MetabolismMinistry of Science and TechnologyShanghaiChina
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10
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Goc A, Rath M, Niedzwiecki A. Composition of naturally occurring compounds decreases activity of Omicron and SARS-CoV-2 RdRp complex. Eur J Microbiol Immunol (Bp) 2022; 12:39-45. [PMID: 35895480 PMCID: PMC9630930 DOI: 10.1556/1886.2022.00009] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/08/2022] [Indexed: 01/10/2023] Open
Abstract
Naturally-occurring compounds are acknowledged for their broad antiviral efficacy. Little is however known about their mutual cooperation. Here, we evaluated in vitro efficacy of the defined mixture of agents against the RdRp complex of the original SARS-CoV-2 and Omicron variant. This composition of vitamin C, N-acetylcysteine, resveratrol, theaflavin, curcumin, quercetin, naringenin, baicalin, and broccoli extract showed to inhibit activity of RdRp/nsp7/nsp8 both these variants. In vitro exposure of recombinant RdRp complex to individual compounds of this composition pointed to quercetin as the driving inhibitory compound. The outcome of this study supports the motion of antiviral efficacy of natural compounds against SARS-CoV-2 and Omicron and implies that their reciprocal or mutual interaction may augment antiviral action through simultaneous effect on different mechanisms. Consequently, this makes it more difficult for an infectious agent to evade all these mechanisms at the same time. Considering the urgency in finding effective prevention, but also side-effects free treatment of COVID-19 our results call for clinical affirmation of the benefits of this micronutrient combination in both preventive and therapeutic aspects. Whether observed effects can be achieved, by concentrations of the active agents used in these in vitro experiments, in in vivo or clinical setting warrants further study.
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Affiliation(s)
- Anna Goc
- Dr. Rath Research Institute, 5941 Optical Ct., San Jose, CA 95138, USA
| | - Matthias Rath
- Dr. Rath Research Institute, 5941 Optical Ct., San Jose, CA 95138, USA
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11
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Wang B, Svetlov D, Bartikofsky D, Wobus CE, Artsimovitch I. Going Retro, Going Viral: Experiences and Lessons in Drug Discovery from COVID-19. Molecules 2022; 27:3815. [PMID: 35744940 PMCID: PMC9228142 DOI: 10.3390/molecules27123815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 12/15/2022] Open
Abstract
The severity of the COVID-19 pandemic and the pace of its global spread have motivated researchers to opt for repurposing existing drugs against SARS-CoV-2 rather than discover or develop novel ones. For reasons of speed, throughput, and cost-effectiveness, virtual screening campaigns, relying heavily on in silico docking, have dominated published reports. A particular focus as a drug target has been the principal active site (i.e., RNA synthesis) of RNA-dependent RNA polymerase (RdRp), despite the existence of a second, and also indispensable, active site in the same enzyme. Here we report the results of our experimental interrogation of several small-molecule inhibitors, including natural products proposed to be effective by in silico studies. Notably, we find that two antibiotics in clinical use, fidaxomicin and rifabutin, inhibit RNA synthesis by SARS-CoV-2 RdRp in vitro and inhibit viral replication in cell culture. However, our mutagenesis studies contradict the binding sites predicted computationally. We discuss the implications of these and other findings for computational studies predicting the binding of ligands to large and flexible protein complexes and therefore for drug discovery or repurposing efforts utilizing such studies. Finally, we suggest several improvements on such efforts ongoing against SARS-CoV-2 and future pathogens as they arise.
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Affiliation(s)
- Bing Wang
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA;
| | | | - Dylan Bartikofsky
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA; (D.B.); (C.E.W.)
| | - Christiane E. Wobus
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA; (D.B.); (C.E.W.)
| | - Irina Artsimovitch
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA;
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12
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Vitamin C and its therapeutic potential in the management of COVID19. Clin Nutr ESPEN 2022; 50:8-14. [PMID: 35871955 PMCID: PMC9166267 DOI: 10.1016/j.clnesp.2022.05.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 04/01/2022] [Accepted: 05/31/2022] [Indexed: 12/18/2022]
Abstract
COVID19 has emerged as one of the worst pandemics in the history of mankind. Several vaccines have been approved by different government agencies worldwide, but data on their efficacy and safety are limited, and distribution remains a massive challenge. As per WHO, personal immunity is vital for protection against COVID19. Earlier, Vitamin C-mediated pathways have been shown to play critical role in boosting immunity attributed to its antioxidant properties. Recently, the involvement of such pathways in protection against COVID19 has been suggested. The controlled doses of Vitamin C administered through intravenous (IV) injections are being studied for determining its role in the prognosis of COVID19. In this article, we have discussed the potential role of Vitamin C in the management in COVID19 patients and presented recent clinical trials data. Additionally, we have elaborated the possibility of administering Vitamin C through inhalers in order to achieve local high concentration and the challenges of such approach.
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13
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Shiao YH. Promising Assays for Examining a Putative Role of Ribosomal Heterogeneity in COVID-19 Susceptibility and Severity. Life (Basel) 2022; 12:203. [PMID: 35207490 PMCID: PMC8880406 DOI: 10.3390/life12020203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 11/17/2022] Open
Abstract
The heterogeneity of ribosomes, characterized by structural variations, arises from differences in types, numbers, and/or post-translational modifications of participating ribosomal proteins (RPs), ribosomal RNAs (rRNAs) sequence variants plus post-transcriptional modifications, and additional molecules essential for forming a translational machinery. The ribosomal heterogeneity within an individual organism or a single cell leads to preferential translations of selected messenger RNA (mRNA) transcripts over others, especially in response to environmental cues. The role of ribosomal heterogeneity in SARS-CoV-2 coronavirus infection, propagation, related symptoms, or vaccine responses is not known, and a technique to examine these has not yet been developed. Tools to detect ribosomal heterogeneity or to profile translating mRNAs independently cannot identify unique or specialized ribosome(s) along with corresponding mRNA substrate(s). Concurrent characterizations of RPs and/or rRNAs with mRNA substrate from a single ribosome would be critical to decipher the putative role of ribosomal heterogeneity in the COVID-19 disease, caused by the SARS-CoV-2, which hijacks the host ribosome to preferentially translate its RNA genome. Such a protocol should be able to provide a high-throughput screening of clinical samples in a large population that would reach a statistical power for determining the impact of a specialized ribosome to specific characteristics of the disease. These characteristics may include host susceptibility, viral infectivity and transmissibility, severity of symptoms, antiviral treatment responses, and vaccine immunogenicity including its side effect and efficacy. In this study, several state-of-the-art techniques, in particular, chemical probing of ribosomal components or rRNA structures, proximity ligation to generate rRNA-mRNA chimeras for sequencing, nanopore gating of individual ribosomes, nanopore RNA sequencing and/or structural analyses, single-ribosome mass spectrometry, and microfluidic droplets for separating ribosomes or indexing rRNAs/mRNAs, are discussed. The key elements for further improvement and proper integration of the above techniques to potentially arrive at a high-throughput protocol for examining individual ribosomes and their mRNA substrates in a clinical setting are also presented.
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Affiliation(s)
- Yih-Horng Shiao
- US Patent Trademark Office, Department of Commerce, Alexandria, VA 22314, USA
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14
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Faisal S, Badshah SL, Kubra B, Sharaf M, Emwas AH, Jaremko M, Abdalla M. Computational Study of SARS-CoV-2 RNA Dependent RNA Polymerase Allosteric Site Inhibition. Molecules 2021; 27:223. [PMID: 35011458 PMCID: PMC8746673 DOI: 10.3390/molecules27010223] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 12/25/2021] [Accepted: 12/26/2021] [Indexed: 01/12/2023] Open
Abstract
The COVID-19 pandemic has caused millions of fatalities since 2019. Despite the availability of vaccines for this disease, new strains are causing rapid ailment and are a continuous threat to vaccine efficacy. Here, molecular docking and simulations identify strong inhibitors of the allosteric site of the SARS-CoV-2 virus RNA dependent RNA polymerase (RdRp). More than one hundred different flavonoids were docked with the SARS-CoV-2 RdRp allosteric site through computational screening. The three top hits were Naringoside, Myricetin and Aureusidin 4,6-diglucoside. Simulation analyses confirmed that they are in constant contact during the simulation time course and have strong association with the enzyme's allosteric site. Absorption, distribution, metabolism, excretion and toxicity (ADMET) data provided medicinal information of these top three hits. They had good human intestinal absorption (HIA) concentrations and were non-toxic. Due to high mutation rates in the active sites of the viral enzyme, these new allosteric site inhibitors offer opportunities to drug SARS-CoV-2 RdRp. These results provide new information for the design of novel allosteric inhibitors against SARS-CoV-2 RdRp.
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Affiliation(s)
- Shah Faisal
- Department of Chemistry, Islamia College University Peshawar, Peshawar 25120, Pakistan; (S.F.); (B.K.)
| | - Syed Lal Badshah
- Department of Chemistry, Islamia College University Peshawar, Peshawar 25120, Pakistan; (S.F.); (B.K.)
| | - Bibi Kubra
- Department of Chemistry, Islamia College University Peshawar, Peshawar 25120, Pakistan; (S.F.); (B.K.)
| | - Mohamed Sharaf
- Department of Biochemistry and Molecular Biology, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China;
- Department of Biochemistry, Faculty of Agriculture, AL-Azhar University, Nasr City, Cairo 11751, Egypt
| | - Abdul-Hamid Emwas
- Core Labs, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia;
| | - Mariusz Jaremko
- Smart-Health Initiative (SHI) and Red Sea Research Center (RSRC), Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Mohnad Abdalla
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Pharmaceutics, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 Cultural West Road, Jinan 250012, China
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15
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Svetlov D, Artsimovitch I. Reductionism Ad Absurdum: The Misadventures of Structural Biology in the Time of Coronavirus. ACS Infect Dis 2021; 7:2948-2952. [PMID: 34613689 PMCID: PMC8507565 DOI: 10.1021/acsinfecdis.1c00492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Indexed: 01/18/2023]
Abstract
The tragic consequences of the COVID-19 pandemic have led to admirable responses by the global scientific community, including a profound acceleration in the pace of research and exchange of findings. However, this has had considerable costs of its own, as erroneous conclusions have propagated faster than researchers have been able to detect and correct them. We illustrate the specific misunderstandings that have resulted from reductionist approaches to the study of SARS-CoV-2 RNA-dependent RNA polymerase (RdRp), which are but one instance of a regrettably growing trend in structural biology. Far from merely being cautionary tales about the conduct of scientific research, these errors have had significant practical impact, by hampering a correct understanding of RdRp structure and mechanism, its inhibition by nucleoside analogues such as remdesivir, and the discovery and characterization of such analogues. After correcting these misunderstandings, we close with several recommendations for a broader correction of the course of scientific research.
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Affiliation(s)
- Dmitri Svetlov
- Svetlov Scientific
Software, Pasadena, California 91106, United States
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA
Biology, The Ohio State University, Columbus, Ohio 43210,
United States
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16
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Abstract
Remdesivir (GS-5734, Veklury®) has remained the only antiviral drug formally approved by the US FDA for the treatment of Covid-19 (SARS-CoV-2 infection). Its key structural features are the fact that it is a C-nucleoside (adenosine) analogue, contains a 1'-cyano function, and could be considered as a ProTide based on the presence of a phosphoramidate group. Its antiviral spectrum and activity in animal models have been well established and so has been its molecular mode of action as a delayed chain terminator of the viral RdRp (RNA-dependent RNA polymerase). Its clinical efficacy has been evaluated, but needs to be optimized with regard to timing, dosage and duration of treatment, and route of administration. Safety, toxicity and pharmacokinetics need to be further addressed, and so are its potential combinations with other drugs such as corticosteroids (i.e. dexamethasone) and ribavirin.
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17
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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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18
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The nucleotide addition cycle of the SARS-CoV-2 polymerase. Cell Rep 2021; 36:109650. [PMID: 34433083 PMCID: PMC8367775 DOI: 10.1016/j.celrep.2021.109650] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/10/2021] [Accepted: 08/11/2021] [Indexed: 12/29/2022] Open
Abstract
Coronaviruses have evolved elaborate multisubunit machines to replicate and transcribe their genomes. Central to these machines are the RNA-dependent RNA polymerase subunit (nsp12) and its intimately associated cofactors (nsp7 and nsp8). We use a high-throughput magnetic-tweezers approach to develop a mechanochemical description of this core polymerase. The core polymerase exists in at least three catalytically distinct conformations, one being kinetically consistent with incorporation of incorrect nucleotides. We provide evidence that the RNA-dependent RNA polymerase (RdRp) uses a thermal ratchet instead of a power stroke to transition from the pre- to post-translocated state. Ultra-stable magnetic tweezers enable the direct observation of coronavirus polymerase deep and long-lived backtracking that is strongly stimulated by secondary structures in the template. The framework we present here elucidates one of the most important structure-dynamics-function relationships in human health today and will form the grounds for understanding the regulation of this complex.
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