scholarly journals Fe-S cofactors in the SARS-CoV-2 RNA-dependent RNA polymerase are potential antiviral targets

Science ◽  
2021 ◽  
pp. eabi5224
Author(s):  
Nunziata Maio ◽  
Bernard A. P. Lafont ◽  
Debangsu Sil ◽  
Yan Li ◽  
J. Martin Bollinger ◽  
...  

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of coronavirus disease 2019 (COVID-19), uses an RNA-dependent RNA polymerase (RdRp) for the replication of its genome and the transcription of its genes. We found that the catalytic subunit of the RdRp, nsp12, ligates two iron-sulfur metal cofactors in sites that were modeled as zinc centers in the available cryo-electron microscopy structures of the RdRp complex. These metal binding sites are essential for replication and for interaction with the viral helicase. Oxidation of the clusters by the stable nitroxide TEMPOL caused their disassembly, potently inhibited the RdRp, and blocked SARS-CoV-2 replication in cell culture. These iron-sulfur clusters thus serve as cofactors for the SARS-CoV-2 RdRp and are targets for therapy of COVID-19.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Goran Kokic ◽  
Hauke S. Hillen ◽  
Dimitry Tegunov ◽  
Christian Dienemann ◽  
Florian Seitz ◽  
...  

AbstractRemdesivir is the only FDA-approved drug for the treatment of COVID-19 patients. The active form of remdesivir acts as a nucleoside analog and inhibits the RNA-dependent RNA polymerase (RdRp) of coronaviruses including SARS-CoV-2. Remdesivir is incorporated by the RdRp into the growing RNA product and allows for addition of three more nucleotides before RNA synthesis stalls. Here we use synthetic RNA chemistry, biochemistry and cryo-electron microscopy to establish the molecular mechanism of remdesivir-induced RdRp stalling. We show that addition of the fourth nucleotide following remdesivir incorporation into the RNA product is impaired by a barrier to further RNA translocation. This translocation barrier causes retention of the RNA 3ʹ-nucleotide in the substrate-binding site of the RdRp and interferes with entry of the next nucleoside triphosphate, thereby stalling RdRp. In the structure of the remdesivir-stalled state, the 3ʹ-nucleotide of the RNA product is matched and located with the template base in the active center, and this may impair proofreading by the viral 3ʹ-exonuclease. These mechanistic insights should facilitate the quest for improved antivirals that target coronavirus replication.


2017 ◽  
Vol 85 (8) ◽  
pp. 1435-1445 ◽  
Author(s):  
Md Munan Shaik ◽  
Nicholus Bhattacharjee ◽  
Mikolaj Feliks ◽  
Kenneth K.-S. Ng ◽  
Martin J. Field

Author(s):  
Goran Kokic ◽  
Hauke S. Hillen ◽  
Dimitry Tegunov ◽  
Christian Dienemann ◽  
Florian Seitz ◽  
...  

Remdesivir is the only FDA-approved drug for the treatment of COVID-19 patients1–4. The active form of remdesivir acts as a nucleoside analogue and inhibits the RNA-dependent RNA polymerase (RdRp) of coronaviruses including SARS-CoV-25–7. Remdesivir is incorporated by the RdRp into the growing RNA product and allows for addition of three more nucleotides before RNA synthesis stalls6,8. Here we use synthetic RNA chemistry, biochemistry and cryo-electron microscopy to establish the molecular mechanism of remdesivir-induced RdRp stalling. We show that addition of the fourth nucleotide following remdesivir incorporation into the RNA product is impaired by a barrier to further RNA translocation. This translocation barrier causes retention of the RNA 3’-nucleotide in the substrate-binding site of the RdRp and interferes with entry of the next nucleoside triphosphate, thereby stalling RdRp. In the structure of the remdesivir-stalled state, the 3’-nucleotide of the RNA product is matched with the template base, and this may prevent proofreading by the viral 3’-exonuclease that recognizes mismatches9,10. These mechanistic insights should facilitate the quest for improved antivirals that target coronavirus replication.


2008 ◽  
Vol 283 (18) ◽  
pp. 12227-12231 ◽  
Author(s):  
Anindito Sen ◽  
J. Bernard Heymann ◽  
Naiqian Cheng ◽  
Jian Qiao ◽  
Leonard Mindich ◽  
...  

Science ◽  
2020 ◽  
Vol 368 (6492) ◽  
pp. 779-782 ◽  
Author(s):  
Yan Gao ◽  
Liming Yan ◽  
Yucen Huang ◽  
Fengjiang Liu ◽  
Yao Zhao ◽  
...  

A novel coronavirus [severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2)] outbreak has caused a global coronavirus disease 2019 (COVID-19) pandemic, resulting in tens of thousands of infections and thousands of deaths worldwide. The RNA-dependent RNA polymerase [(RdRp), also named nsp12] is the central component of coronaviral replication and transcription machinery, and it appears to be a primary target for the antiviral drug remdesivir. We report the cryo–electron microscopy structure of COVID-19 virus full-length nsp12 in complex with cofactors nsp7 and nsp8 at 2.9-angstrom resolution. In addition to the conserved architecture of the polymerase core of the viral polymerase family, nsp12 possesses a newly identified β-hairpin domain at its N terminus. A comparative analysis model shows how remdesivir binds to this polymerase. The structure provides a basis for the design of new antiviral therapeutics that target viral RdRp.


BIOspektrum ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 49-53
Author(s):  
Patrick Cramer ◽  
Goran Kokic ◽  
Christian Dienemann ◽  
Claudia Höbartner ◽  
Hauke S. Hillen

AbstractCoronaviruses use an RNA-dependent RNA polymerase to replicate and transcribe their RNA genome. The structure of the SARS-CoV-2 polymerase was determined by cryo-electron microscopy within a short time in spring 2020. The structure explains how the viral enzyme synthesizes RNA and how it replicates the exceptionally large genome in a processive manner. The most recent structure-function studies further reveal the mechanism of polymerase inhibition by remdesivir, an approved drug for the treatment of COVID-19.


Science ◽  
2021 ◽  
pp. eabf3546
Author(s):  
Pramod R. Bhatt ◽  
Alain Scaiola ◽  
Gary Loughran ◽  
Marc Leibundgut ◽  
Annika Kratzel ◽  
...  

Programmed ribosomal frameshifting is a key event during translation of the SARS-CoV-2 RNA genome allowing synthesis of the viral RNA-dependent RNA polymerase and downstream proteins. Here we present the cryo-electron microscopy structure of a translating mammalian ribosome primed for frameshifting on the viral RNA. The viral RNA adopts a pseudoknot structure that lodges at the entry to the ribosomal mRNA channel to generate tension in the mRNA and promote frameshifting, whereas the nascent viral polyprotein forms distinct interactions with the ribosomal tunnel. Biochemical experiments validate the structural observations and reveal mechanistic and regulatory features that influence frameshifting efficiency. Finally, we compare compounds previously shown to reduce frameshifting with respect to their ability to inhibit SARS-CoV-2 replication, establishing coronavirus frameshifting as a target for antiviral intervention.


Author(s):  
Brandon Malone ◽  
James Chen ◽  
Qi Wang ◽  
Eliza Llewellyn ◽  
Young Joo Choi ◽  
...  

AbstractBacktracking, the reverse motion of the transcriptase enzyme on the nucleic acid template, is a universal regulatory feature of transcription in cellular organisms but its role in viruses is not established. Here we present evidence that backtracking extends into the viral realm, where backtracking by the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) may aid viral transcription and replication. Structures of SARS-CoV-2 RdRp bound to the essential nsp13 helicase and RNA suggested the helicase facilitates backtracking. We use cryo-electron microscopy, RNA-protein crosslinking, and unbiased molecular dynamics simulations to characterize SARS-CoV-2 RdRp backtracking. The results establish that the single-stranded 3’-segment of the product-RNA generated by backtracking extrudes through the RdRp NTP-entry tunnel, that a mismatched nucleotide at the product-RNA 3’-end frays and enters the NTP-entry tunnel to initiate backtracking, and that nsp13 stimulates RdRp backtracking. Backtracking may aid proofreading, a crucial process for SARS-CoV-2 resistance against antivirals.Significance StatementThe COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 genome is replicated and transcribed by its RNA-dependent RNA polymerase (RdRp), which is the target for antivirals such as remdesivir. We use a combination of approaches to show that backtracking (backwards motion of the RdRp on the template RNA) is a feature of SARS-CoV-2 replication/transcription. Backtracking may play a critical role in proofreading, a crucial process for SARS-CoV-2 resistance against many antivirals.


Science ◽  
2020 ◽  
Vol 368 (6498) ◽  
pp. 1499-1504 ◽  
Author(s):  
Wanchao Yin ◽  
Chunyou Mao ◽  
Xiaodong Luan ◽  
Dan-Dan Shen ◽  
Qingya Shen ◽  
...  

The pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global crisis. Replication of SARS-CoV-2 requires the viral RNA-dependent RNA polymerase (RdRp) enzyme, a target of the antiviral drug remdesivir. Here we report the cryo–electron microscopy structure of the SARS-CoV-2 RdRp, both in the apo form at 2.8-angstrom resolution and in complex with a 50-base template-primer RNA and remdesivir at 2.5-angstrom resolution. The complex structure reveals that the partial double-stranded RNA template is inserted into the central channel of the RdRp, where remdesivir is covalently incorporated into the primer strand at the first replicated base pair, and terminates chain elongation. Our structures provide insights into the mechanism of viral RNA replication and a rational template for drug design to combat the viral infection.


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