Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
1.
ACS Chem Biol ; 16(8): 1469-1481, 2021 08 20.
Article in English | MEDLINE | ID: covidwho-1387143

ABSTRACT

The programmed -1 ribosomal frameshifting element (PFSE) of SARS-CoV-2 is a well conserved structured RNA found in all coronaviruses' genomes. By adopting a pseudoknot structure in the presence of the ribosome, the PFSE promotes a ribosomal frameshifting event near the stop codon of the first open reading frame Orf1a during translation of the polyprotein pp1a. Frameshifting results in continuation of pp1a via a new open reading frame, Orf1b, that produces the longer pp1ab polyprotein. Polyproteins pp1a and pp1ab produce nonstructural proteins NSPs 1-10 and NSPs 1-16, respectively, which contribute vital functions during the viral life cycle and must be present in the proper stoichiometry. Both drugs and sequence alterations that affect the stability of the -1 programmed ribosomal frameshifting element disrupt the stoichiometry of the NSPs produced, which compromise viral replication. For this reason, the -1 programmed frameshifting element is considered a promising drug target. Using chaperone assisted RNA crystallography, we successfully crystallized and solved the three-dimensional structure of the PFSE. We observe a three-stem H-type pseudoknot structure with the three stems stacked in a vertical orientation stabilized by two triple base pairs at the stem 1/stem 2 and stem 1/stem 3 junctions. This structure provides a new conformation of PFSE distinct from the bent conformations inferred from midresolution cryo-EM models and provides a high-resolution framework for mechanistic investigations and structure-based drug design.


Subject(s)
Crystallography/methods , Frameshifting, Ribosomal/physiology , Molecular Chaperones , RNA, Viral/metabolism , SARS-CoV-2/metabolism , Humans , Models, Molecular , Nucleic Acid Conformation , RNA, Viral/genetics , Ribosomes/metabolism , SARS-CoV-2/genetics , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Proteins/metabolism , Virus Replication/physiology
2.
Viruses ; 13(8)2021 08 18.
Article in English | MEDLINE | ID: covidwho-1360825

ABSTRACT

Recent outbreaks of zoonotic coronaviruses, such as Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have caused tremendous casualties and great economic shock. Although some repurposed drugs have shown potential therapeutic efficacy in clinical trials, specific therapeutic agents targeting coronaviruses have not yet been developed. During coronavirus replication, a replicase gene cluster, including RNA-dependent RNA polymerase (RdRp), is alternatively translated via a process called -1 programmed ribosomal frameshift (-1 PRF) by an RNA pseudoknot structure encoded in viral RNAs. The coronavirus frameshifting has been identified previously as a target for antiviral therapy. In this study, the frameshifting efficiencies of MERS-CoV, SARS-CoV and SARS-CoV-2 were determined using an in vitro -1 PRF assay system. Our group has searched approximately 9689 small molecules to identify potential -1 PRF inhibitors. Herein, we found that a novel compound, 2-(5-acetylthiophen-2yl)furo[2,3-b]quinoline (KCB261770), inhibits the frameshifting of MERS-CoV and effectively suppresses viral propagation in MERS-CoV-infected cells. The inhibitory effects of 87 derivatives of furo[2,3-b]quinolines were also examined showing less prominent inhibitory effect when compared to compound KCB261770. We demonstrated that KCB261770 inhibits the frameshifting without suppressing cap-dependent translation. Furthermore, this compound was able to inhibit the frameshifting, to some extent, of SARS-CoV and SARS-CoV-2. Therefore, the novel compound 2-(5-acetylthiophen-2yl)furo[2,3-b]quinoline may serve as a promising drug candidate to interfere with pan-coronavirus frameshifting.


Subject(s)
Antiviral Agents/pharmacology , Frameshifting, Ribosomal/drug effects , Middle East Respiratory Syndrome Coronavirus/drug effects , Quinolines/pharmacology , SARS Virus/drug effects , SARS-CoV-2/drug effects , A549 Cells , Animals , Cell Line , Frameshifting, Ribosomal/physiology , Humans , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/physiology , SARS Virus/genetics , SARS Virus/physiology , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Small Molecule Libraries , Viral Zoonoses/virology , Virus Replication/drug effects
3.
Bioorg Med Chem ; 46: 116356, 2021 09 15.
Article in English | MEDLINE | ID: covidwho-1347508

ABSTRACT

The ongoing COVID-19 pandemic, periodic recurrence of viral infections, and the emergence of challenging variants has created an urgent need of alternative therapeutic approaches to combat the spread of viral infections, failing to which may pose a greater risk to mankind in future. Resilience against antiviral drugs or fast evolutionary rate of viruses is stressing the scientific community to identify new therapeutic approaches for timely control of disease. Host metabolic pathways are exquisite reservoir of energy to viruses and contribute a diverse array of functions for successful replication and pathogenesis of virus. Targeting the host factors rather than viral enzymes to cease viral infection, has emerged as an alternative antiviral strategy. This approach offers advantage in terms of increased threshold to viral resistance and can provide broad-spectrum antiviral action against different viruses. The article here provides substantial review of literature illuminating the host factors and molecular mechanisms involved in innate/adaptive responses to viral infection, hijacking of signalling pathways by viruses and the intracellular metabolic pathways required for viral replication. Host-targeted drugs acting on the pathways usurped by viruses are also addressed in this study. Host-directed antiviral therapeutics might prove to be a rewarding approach in controlling the unprecedented spread of viral infection, however the probability of cellular side effects or cytotoxicity on host cell should not be ignored at the time of clinical investigations.


Subject(s)
Antiviral Agents/pharmacology , Positive-Strand RNA Viruses/drug effects , Animals , Cytokines/metabolism , Frameshifting, Ribosomal/drug effects , Frameshifting, Ribosomal/physiology , Glycosylation/drug effects , Humans , Immunity/drug effects , Immunity/physiology , Lipid Metabolism/drug effects , Lipid Metabolism/physiology , Metabolic Networks and Pathways/drug effects , Metabolic Networks and Pathways/physiology , Polyamines/metabolism , Positive-Strand RNA Viruses/physiology , Signal Transduction/drug effects , Signal Transduction/physiology , Ubiquitination/drug effects , Ubiquitination/physiology
4.
Virology ; 554: 75-82, 2021 02.
Article in English | MEDLINE | ID: covidwho-989370

ABSTRACT

Human population growth, climate change, and globalization are accelerating the emergence of novel pathogenic viruses. In the past two decades alone, three such members of the coronavirus family have posed serious threats, spurring intense efforts to understand their biology as a way to identify targetable vulnerabilities. Coronaviruses use a programmed -1 ribosomal frameshift (-1 PRF) mechanism to direct synthesis of their replicase proteins. This is a critical switch in their replication program that can be therapeutically targeted. Here, we discuss how nearly half a century of research into -1 PRF have provided insight into the virological importance of -1 PRF, the molecular mechanisms that drive it, and approaches that can be used to manipulate it towards therapeutic outcomes with particular emphasis on SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus/drug effects , Coronavirus/genetics , Frameshifting, Ribosomal/drug effects , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Coronavirus/growth & development , Coronavirus/physiology , Coronavirus Infections/drug therapy , Frameshifting, Ribosomal/genetics , Frameshifting, Ribosomal/physiology , Gene Expression Regulation, Viral , Humans , Mutation , Nucleic Acid Conformation , RNA, Viral/chemistry , RNA, Viral/genetics , RNA, Viral/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , SARS-CoV-2/growth & development , SARS-CoV-2/physiology , Virus Replication
SELECTION OF CITATIONS
SEARCH DETAIL