Discovery of Potent Non-Nucleoside Inhibitors of Dengue Viral RNA-Dependent RNA Polymerase from a Fragment Hit Using Structure-Based Drug Design

2016 ◽  
Vol 59 (8) ◽  
pp. 3935-3952 ◽  
Author(s):  
Fumiaki Yokokawa ◽  
Shahul Nilar ◽  
Christian G. Noble ◽  
Siew Pheng Lim ◽  
Ranga Rao ◽  
...  
2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohamed MFA ◽  
◽  
Sayed AM ◽  
Abdelmohsen UR ◽  
Nafady A ◽  
...  

The novel coronavirus disease that initially appeared in 2019, commonly identified as COVID-19 is an acute infectious disease precipitated by the SARSCoV- 2 and has become a severe pandemic health crisis. People stricken with a severe case of COVID-19 are subject to a relatively higher mortality rate, which is brought about predominantly by the difficulty of having potent and specific antiviral drugs for its treatment. In this context, the viral RNA-dependent RNA polymerase (RdRp) is an attractive target for antiviral inhibitors, mainly because of its essential role in processing the polyproteins translated from viral RNA. Moreover, histone deacetylases inhibitors represent one of the most promising antiviral agents. Therefore, in this contribution, the in silico structure-based drug design approach was employed to identify novel structural characteristics for the potential repurposed activity of HDACIs as antivirals against COVID-19. Herein, 12 HDAC inhibitors were screened to explore their potential anti-viral activity against RNA-dependent RNA polymerase (RdRp) (6NUR). Results revealed that large number of the screened HDAC inhibitors are strongly bound into the active binding site of crystallographic structure of RNA-dependent RNA polymerase (RdRp) (6NUR) with lowest CDOCKER energy and CDOCKER interaction energy are very close to those of the control drug remdesivir. Importantly, the virtually screened HDAC inhibitors, particularly, Givinostat, Pracinostat, Panobinostat, Romidepsin (FK228) and its active metabolite (RedF) could be promising candidates for COVID-19 RNA-dependent RNA polymerase (RdRp) inhibitors. Significantly, these inhibitors should be evaluated on their effectivity when treating COVID-19, specifically using the drugs that have been approved for clinical trials with limited toxicity.


2020 ◽  
Vol 27 ◽  
Author(s):  
Sehrish Bano ◽  
Abdul Hameed ◽  
Mariya Al-Rashida ◽  
Shafia Iftikhar ◽  
Jamshed Iqbal

Background: The 2019 novel coronavirus (2019-nCoV), also known as coronavirus 2 (SARS-CoV-2) acute respiratory syndrome has recently emerged and continued to spread rapidly with high level of mortality and morbidity rates. Currently, no efficacious therapy is available to relieve coronavirus infections. As new drug design and development takes much time, there is a possibility to find an effective treatment from existing antiviral agents. Objective: In this case, there is a need to find out the relationship between possible drug targets and mechanism of action of antiviral drugs. This review discusses about the efforts to develop drug from known or new molecules. Methods: Viruses usually have two structural integrities, proteins and nucleic acids, both of which can be possible drug targets. Herein, we systemically discuss the structural-functional relationships of the spike, 3-chymotrypsin-like protease (3CLpro), papain like protease (PLpro) and RNA-dependent RNA polymerase (RdRp), as these are prominent structural features of corona virus. Certain antiviral drugs such as Remdesivir are RNA dependent RNA polymerase inhibitor. It has the ability to terminate RNA replication by inhibiting ATP. Results: It is reported that ATP is involved in synthesis of coronavirus non-structural proteins from 3CLpro and PLpro. Similarly, mechanisms of action of many other antiviral agents has been discussed in this review. It will provide new insights into the mechanism of inhibition, and let us develop new therapeutic antiviral approaches against novel SARS-CoV-2 coronavirus. Conclusion: In conclusion, this review summarizes recent progress in developing protease inhibitors for SARS-CoV-2.


2017 ◽  
Vol 91 (21) ◽  
Author(s):  
Nidhi Kaushik ◽  
Chandru Subramani ◽  
Saumya Anang ◽  
Rajagopalan Muthumohan ◽  
Shalimar ◽  
...  

ABSTRACT Hepatitis E virus (HEV) causes an acute, self-limiting hepatitis in healthy individuals and leads to chronic disease in immunocompromised individuals. HEV infection in pregnant women results in a more severe outcome, with the mortality rate going up to 30%. Though the virus usually causes sporadic infection, epidemics have been reported in developing and resource-starved countries. No specific antiviral exists against HEV. A combination of interferon and ribavirin therapy has been used to control the disease with some success. Zinc is an essential micronutrient that plays crucial roles in multiple cellular processes. Zinc salts are known to be effective in reducing infections caused by few viruses. Here, we investigated the effect of zinc salts on HEV replication. In a human hepatoma cell (Huh7) culture model, zinc salts inhibited the replication of genotype 1 (g-1) and g-3 HEV replicons and g-1 HEV infectious genomic RNA in a dose-dependent manner. Analysis of a replication-defective mutant of g-1 HEV genomic RNA under similar conditions ruled out the possibility of zinc salts acting on replication-independent processes. An ORF4-Huh7 cell line-based infection model of g-1 HEV further confirmed the above observations. Zinc salts did not show any effect on the entry of g-1 HEV into the host cell. Furthermore, our data reveal that zinc salts directly inhibit the activity of viral RNA-dependent RNA polymerase (RdRp), leading to inhibition of viral replication. Taken together, these studies unravel the ability of zinc salts in inhibiting HEV replication, suggesting their possible therapeutic value in controlling HEV infection. IMPORTANCE Hepatitis E virus (HEV) is a public health concern in resource-starved countries due to frequent outbreaks. It is also emerging as a health concern in developed countries owing to its ability to cause acute and chronic infection in organ transplant and immunocompromised individuals. Although antivirals such as ribavirin have been used to treat HEV cases, there are known side effects and limitations of such therapy. Our discovery of the ability of zinc salts to block HEV replication by virtue of their ability to inhibit the activity of viral RdRp is important because these findings pave the way to test the efficacy of zinc supplementation therapy in HEV-infected patients. Since zinc supplementation therapy is known to be safe in healthy individuals and since high-dose zinc is used in the treatment of Wilson's disease, it may be possible to control HEV-associated health problems following a similar treatment regimen.


1999 ◽  
Vol 73 (1) ◽  
pp. 198-204 ◽  
Author(s):  
Scott Stevenson Stawicki ◽  
C. Cheng Kao

ABSTRACT RNA synthesis during viral replication requires specific recognition of RNA promoters by the viral RNA-dependent RNA polymerase (RdRp). Four nucleotides (−17, −14, −13, and −11) within the brome mosaic virus (BMV) subgenomic core promoter are required for RNA synthesis by the BMV RdRp (R. W. Siegel et al., Proc. Natl. Acad. Sci. USA 94:11238–11243, 1997). The spatial requirements for these four nucleotides and the initiation (+1) cytidylate were examined in RNAs containing nucleotide insertions and deletions within the BMV subgenomic core promoter. Spatial perturbations between nucleotides −17 and −11 resulted in decreased RNA synthesis in vitro. However, synthesis was still dependent on the key nucleotides identified in the wild-type core promoter and the initiation cytidylate. In contrast, changes between nucleotides −11 and +1 had a less severe effect on RNA synthesis but resulted in RNA products initiated at alternative locations in addition to the +1 cytidylate. The results suggest a degree of flexibility in the recognition of the subgenomic promoter by the BMV RdRp and are compared with functional regions in other DNA and RNA promoters.


Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2360 ◽  
Author(s):  
Sonia de Castro ◽  
Cristina Ferrer-Orta ◽  
Alberto Mills ◽  
Gloria Fernández-Cureses ◽  
Federico Gago ◽  
...  

Foot-and-mouth disease virus (FMDV) is an RNA virus belonging to the Picornaviridae family that contains three small viral proteins (VPgs), named VPg1, VPg2 and VPg3, linked to the 5′-end of the viral genome. These VPg proteins act as primers for RNA replication, which is initiated by the consecutive binding of two UMP molecules to the hydroxyl group of Tyr3 in VPg. This process, termed uridylylation, is catalyzed by the viral RNA-dependent RNA polymerase named 3Dpol. 5-Fluorouridine triphosphate (FUTP) is a potent competitive inhibitor of VPg uridylylation. Peptide analysis showed FUMP covalently linked to the Tyr3 of VPg. This fluorouridylylation prevents further incorporation of the second UMP residue. The molecular basis of how the incorporated FUMP blocks the incorporation of the second UMP is still unknown. To investigate the mechanism of inhibition of VPg uridylylation by FUMP, we have prepared a simplified 15-mer model of VPg1 containing FUMP and studied its x-ray crystal structure in complex with 3Dpol. Unfortunately, the fluorouridylylated VPg1 was disordered and not visible in the electron density maps; however, the structure of 3Dpol in the presence of VPg1-FUMP showed an 8 Å movement of the β9-α11 loop of the polymerase towards the active site cavity relative to the complex of 3Dpol with VPg1-UMP. The conformational rearrangement of this loop preceding the 3Dpol B motif seems to block the access of the template nucleotide to the catalytic cavity. This result may be useful in the design of new antivirals against not only FMDV but also other picornaviruses, since all members of this family require the uridylylation of their VPg proteins to initiate the viral RNA synthesis.


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