Allosteric inhibition of dengue virus RNA-dependent RNA polymerase by Litsea cubeba phytochemicals: a computational study.

RNA-dependent RNA polymerase (RdRp) is considered a potential drug target for dengue virus (DENV) inhibition and has attracted attention in antiviral drug discovery. Here, we screened 121 natural compounds from Litsea cubeba against DENV RdRp using various approaches of computer-based drug discovery. Notably, we identified four potential compounds (Ushinsunine, Cassameridine, (+)-Epiexcelsin, (-)-Phanostenine) with good binding scores and allosteric interactions with the target protein. Moreover, molecular dynamics simulation studies were done to check the conformational stability of the complexes under given conditions. Additionally, we performed post-simulation analysis to find the stability of potential drugs in the target protein. The findings suggest Litsea cubeba-derived phytomolecules as a therapeutic solution to control DENV infection.Communicated by Ramaswamy H. Sarma.

Repurposing of SARS-CoV-2 compounds against Marburg Virus using MD simulation, mm/GBSA, PCA analysis, and free energy landscape.

The significant mortality rate associated with Marburg virus infection made it the greatest hazard among infectious diseases. Drug repurposing using in silico methods has been crucial in identifying potential compounds that could prevent viral replication by targeting the virus's primary proteins. This study aimed at repurposing the drugs of SARS-CoV-2 for identifying potential candidates against the matrix protein VP40 of the Marburg virus. Virtual screening was performed where the control compound, Nilotinib, showed a binding score of -9.99 kcal/mol. Based on binding scores, hit compounds 9549298, 11960895, 44545852, 51039094, and 89670174 were selected that had a lower binding score than the control. Subsequent molecular dynamics (MD) simulation revealed that compound 9549298 consistently formed a hydrogen bond with the residue Gln290. This was observed both in molecular docking and MD simulation poses, indicating a strong and significant interaction with the protein. 11960895 had the most stable and consistent RMSD pattern exhibited in 100 ns simulation, while 9549298 had the most identical RMSD plot compared to the control molecule. MM/PBSA analysis showed that the binding free energy (ΔG) of 9549298 and 11960895 was lower than the control, with -30.84 and -38.86 kcal/mol, respectively. It was observed by the PCA (principal component analysis) and FEL (free energy landscape) analysis that compounds 9549298 and 11960895 had lesser conformational variation. Overall, this study proposed 9549298 and 11960895 as potential binders of VP40 MARV that can cause its inhibition, however it inherently lacks experimental validation. Furthermore, the study proposes in-vitro experiments as the next step to validate these computational findings, offering a practical approach to further explore these compounds' potential as antiviral agents.Communicated by Ramaswamy H. Sarma.

Exploring plant-derived small molecules as inhibitors of Marburg virus RNA binding protein activity.

The search for antiviral medications is greatly influenced by the hunt for potent inhibitors of viral proteins. To find possible inhibitors of the RNA binding activity of the Marburg virus VP35 protein, we used a thorough in silico drug discovery approach in this investigation. A comprehensive virtual screening process, followed by a detailed MMGBSA analysis, led to the discovery of four potential inhibitory compounds viz. Kudzuisoflavone A, Miquelianin, Rutin, and Protopseudohypericin. They were identified from an extensive library of phytomolecules derived from three medicinal plants: Adiantum capillus-veneris, Hypericum perforatum, and Pueraria montana. In molecular dynamics (MD) simulations, all these compounds showed steady binding to the target protein and favourable interactions. Notably, the free binding energies of all the selected compounds were better than the myricetin, a well-known blocker of the VP35 protein of the Ebola virus. Overall, this investigation offers insightful information about the molecular interactions and binding dynamics of the identified inhibitors' binding to the VP35 protein of the Marburg virus. The findings highlight the potential of three particular medicinal plants as sources of key chemicals for the creation of brand-new Marburg virus antiviral drugs. More experimental validation and optimization of the identified inhibitors are necessary in order to transform these findings into effective medicines for treating Marburg virus infections.Communicated by Ramaswamy H. Sarma.

Inhibition of Mycobacterium tuberculosis resuscitation-promoting factor B (RpfB) by microbially derived natural compounds: a computational study.

The majority of the world population (around 25%) has latent Mycobacterium tuberculosis (Mtb) infection, among which only 5-10% of individuals develop active tuberculosis (TB), and 90-95% continue to have latent tuberculosis infection. This makes it the biggest global health concern. It has been reported that the resuscitation-promoting factor B (RpfB) is an exciting potential target for tuberculosis drug discovery due to its significant role in the reactivation of latent TB infection to an active infection. Several attempts have been made to investigate potential inhibitors against RpfB utilizing in-silico approaches. The present study also utilized a computational approach to investigate microbially derived natural compounds against the Mtb RpfB protein which is a very cost-effective This evaluation used structure-based virtual screening (SBVS), drug-likeness profiling, molecular docking, molecular dynamics simulation, and free-binding energy calculations. Six potential natural compounds, viz. Cyclizidine I, Boremexin C, Xenocoumacin 2, PM-94128, Cutinostatin B, and (+)1-O-demethylvariecolorquinone A were selected, which displayed a potential binding affinity between -52.39 and -60.87 Kcal/mol MMGBSA score and docking energy between -7.307 Kcal/mol to -6.972 Kcal/mol. All the complexes showed acceptable stability (<2.7 Å RMSD) during 100 ns MD simulation time except the RpfB protein-xenocoumacin 2 complex. This result exhibited that the selected compounds have high efficiency in inhibiting the Mtb RpfB and can be taken into account for additional in vitro and in vivo experimental validation.Communicated by Ramaswamy H. Sarma.

A Multifaceted Computational Approach to Understanding the MERS-CoV Main Protease and Brown Algae Compounds' Interaction.

Middle East Respiratory Syndrome (MERS) is a viral respiratory disease caused b a special type of coronavirus called MERS-CoV. In the search for effective substances against the MERS-CoV main protease, we looked into compounds from brown algae, known for their medicinal benefits. From a set of 1212 such compounds, our computer-based screening highlighted four-CMNPD27819, CMNPD1843, CMNPD4184, and CMNPD3156. These showed good potential in how they might attach to the MERS-CoV protease, comparable to a known inhibitor. We confirmed these results with multiple computer tests. Studies on the dynamics and steadiness of these compounds with the MERS-CoV protease were performed using molecular dynamics (MD) simulations. Metrics like RMSD and RMSF showed their stability. We also studied how these compounds and the protease interact in detail. An analysis technique, PCA, showed changes in atomic positions over time. Overall, our computer studies suggest brown algae compounds could be valuable in fighting MERS. However, experimental validation is needed to prove their real-world effectiveness.

Assessing the inhibitory potential of anti-dengue compounds against Japanese encephalitis virus RNA dependent RNA polymerase: an in silico study.

Japanese encephalitis (JE), a neurological infection of severe nature, is caused by the Japanese encephalitis virus (JEV) and is transmitted by the mosquito vector. The polymerase domain of Non-structural 5 (NS5), which is also referred to as RdRp (RNA-dependent RNA polymerase), is considered a potential therapeutic target for JEV. The present study employed molecular dynamics modelling and high-throughput virtual screening to evaluate the possible antiviral activity of anti-dengue drugs against JEV RdRp. Furthermore, a ranking was performed utilising the MM/GBSA analysis to identify the three most promising compounds. Compound ID 57409246 exhibited the highest binding affinity with the protein, as evidenced by its minimum binding free energy of -72.96 kcal/mole. In contrast, the other two compounds had minimum binding free energies of -67.57 and -59.19 kcal/mole, respectively. Upon conducting a 100 nanosecond molecular dynamics simulation to confirm the binding of the chemical complexes, it was observed that the three hits, namely 57409246, 70683874, and 44577154, exhibited a consistent and stable RMSD. Subsequently, the binding strength of the trajectory was confirmed through MM/GBSA analysis. The compounds 70683874 and 57409246 exhibited the lowest binding free energies, which were -97.58 kcal/mol and -96.38 kcal/mol, respectively. The binding free energy (ΔG Bind) values for the native ligand ATP and molecule 44577154 were -65.64 kcal/mol and -69.44 kcal/mol, respectively. Overall, compared to the native ligand ATP, all three compounds exhibited higher binding affinity. The study proposes three anti-dengue molecules as a potential remedy for JE, which can be confirmed through in vitro and in vivo investigations.Communicated by Ramaswamy H. Sarma.

A multi-targeted computational drug discovery approach for repurposing tetracyclines against monkeypox virus.

Monkeypox viral infection is an emerging threat and a major concern for the human population. The lack of drug molecules to treat this disease may worsen the problem. Identifying potential drug targets can significantly improve the process of developing potent drug molecules for treating monkeypox. The proteins responsible for viral replication are attractive drug targets. Identifying potential inhibitors from known drug molecules that target these proteins can be key to finding a cure for monkeypox. In this work, two viral proteins, DNA-dependent RNA polymerase (DdRp) and viral core cysteine proteinase, were considered as potential drug targets. Sixteen antibiotic drugs from the tetracycline class were screened against both viral proteins through high-throughput virtual screening. These tetracycline class of antibiotic drugs have the ability to inhibit bacterial protein synthesis, which makes these antibiotics drugs a prominent candidate for drug repurposing. Based on the screening result obtained against DdRp, top two compounds, namely Tigecycline and Eravacycline with docking scores of - 8.88 and - 7.87 kcal/mol, respectively, were selected for further analysis. Omadacycline and minocycline, with docking scores of - 10.60 and - 7.51 kcal/mol, are the top two compounds obtained after screening proteinase with the drug library. These compounds, along with reference compounds GTP for DdRp and tecovirimat for proteinase, were used to form protein-ligand complexes, followed by their evaluation through a 300 ns molecular dynamic simulation. The MM/GBSA binding free energy calculation and principal components analysis of these selected complexes were also conducted for understanding the dynamic stability and binding affinity of these compounds with respective target proteins. Overall, this study demonstrates the repurposing of tetracycline-derived drugs as a therapeutic solution for monkeypox viral infection.

Unveiling the antiviral potential of Plant compounds from the Meliaceae family against the Zika virus through QSAR modeling and MD simulation analysis.

Zika virus (ZIKV) is a flavivirus transmitted by mosquitoes, causing neurological disorders and congenital malformations. RNA-dependent RNA polymerase (RdRp) is one of its essential enzymes and a promising drug target for antiviral therapy due to its involvement in the growth and multiplication of the virus. In this study, we conducted a QSAR-based chemical library screening from the Meliaceae family to identify potential RdRp inhibitors. The QSAR model was built using the known inhibitors of RdRp NS5 of ZIKV and their biological activity (EC50), along with the structural and chemical characteristics of the compounds. The top two hit compounds were selected from QSAR screening for further analysis using molecular docking to evaluate their binding energies and intermolecular interactions with RdRp, including the critical residue Trp485. Furthermore, molecular dynamics (MD) simulations were performed to evaluate their binding stability and flexibility upon binding to RdRp. The MD results showed that the selected compounds formed stable complexes with RdRp, and their binding interactions were similar to those observed for the native ligand. The binding energies of the top two hits (-8.6 and -7.7 kcal/mole) were comparable to those of previously reported ZIKV RdRp inhibitors (-8.9 kcal/mole). The compound IMPHY009135 showed the strongest binding affinity with RdRp, forming multiple hydrogen bonds and hydrophobic interactions with key residues. However, compound IMPHY009276 showed the most stable and consistent RMSD, which was similar to the native ligand. Our findings suggest that IMPHY009135 and IMPHY009276 are potential lead compounds for developing novel antiviral agents against ZIKV.Communicated by Ramaswamy H. Sarma.

Repurposing of antibacterial compounds for suppression of Mycobacterium tuberculosis dormancy reactivation by targeting resuscitation-promoting factors B.

Tuberculosis infection has always been a global concern for public health, and the mortality rate has increased tremendously every year. The ability of the resuscitation Mycobacterium tuberculosis (Mtb) from the dormant state is one of the major reasons for the epidemic spread of tuberculosis infection, especially latent tuberculosis infection (LTBI). The element that encourages resuscitation, RpfB (resuscitation-promoting factors B), is mostly in charge of bringing Mtb out of slumber. This reason makes RpfB a promising target for developing tuberculosis drugs because of the effects of latent tuberculosis. Therefore, this work was executed using a computational three-level screening of the Selleckhem antibiotics database consisting of 462 antibiotics against the ligand binding region of the RpfB protein, followed by an estimation of binding free energy for ideal identification and confirmation of potential RpfB inhibitor. Subsequently, three antibiotic drug molecules, i.e., Amikacin hydrate (-66.87 kcal/mol), Isepamicin sulphate (-60.8 kcal/mol), and Bekanamycin (-46.89 kcal/mol), were selected on the basis of their binding free energy value for further computational studies in comparison to reference ligand, 4-benzoyl-2-nitrophenyl thiocyanate (NPT7). Based on the intermolecular interaction profiling, 200 ns molecular dynamic simulation (MD), post-simulation analysis and principal component analysis (PCA), the selected antibiotics showed substantial stability with the RpfB protein compared to the NPT7 inhibitor. Conclusively based on the computational results, the preferred drugs can be potent inhibitors of the RpfB protein, which can be further validated using in vivo research and in vitro enzyme inhibition to understand their therapeutic activity against tuberculosis infection.Communicated by Ramaswamy H. Sarma.

Cheminformatics Strategies Unlock Marburg Virus VP35 Inhibitors from Natural Compound Library.

The Ebola virus and its close relative, the Marburg virus, both belong to the family Filoviridae and are highly hazardous and contagious viruses. With a mortality rate ranging from 23% to 90%, depending on the specific outbreak, the development of effective antiviral interventions is crucial for reducing fatalities and mitigating the impact of Marburg virus outbreaks. In this investigation, a virtual screening approach was employed to evaluate 2042 natural compounds for their potential interactions with the VP35 protein of the Marburg virus. Average and worst binding energies were calculated for all 20 poses, and compounds that exhibited binding energies <-6 kcal/mol in both criteria were selected for further analysis. Based on binding energies, only six compounds (Estradiol benzoate, INVEGA (paliperidone), Isosilybin, Protopanaxadiol, Permethrin, and Bufalin) were selected for subsequent investigations, focusing on interaction analysis. Among these selected compounds, Estradiol benzoate, INVEGA (paliperidone), and Isosilybin showed strong hydrogen bonds, while the others did not. In this study, the compounds Myricetin, Isosilybin, and Estradiol benzoate were subjected to a molecular dynamics (MD) simulation and free binding energy calculation using MM/GBSA analysis. The reference component Myricetin served as a control. Estradiol benzoate exhibited the most stable and consistent root-mean-square deviation (RMSD) values, whereas Isosilybin showed significant fluctuations in RMSD. The compound Estradiol benzoate exhibited the lowest ΔG binding free energy (-22.89 kcal/mol), surpassing the control compound's binding energy (-9.29 kcal/mol). Overall, this investigation suggested that Estradiol benzoate possesses favorable binding free energies, indicating a potential inhibitory mechanism against the VP35 protein of the Marburg virus. The study proposes that these natural compounds could serve as a therapeutic option for preventing Marburg virus infection. However, experimental validation is required to further corroborate these findings.

Investigating the Mechanism of Action of Anti-Dengue Compounds as Potential Binders of Zika Virus RNA-Dependent RNA Polymerase.

The World Health Organization (WHO) has designated the Zika virus (ZIKV) as a significant risk to the general public's health. Currently, there are no vaccinations or medications available to treat or prevent infection with the Zika virus. Thus, it is urgently required to develop a highly efficient therapeutic molecule. In the presented study, a computationally intensive search was carried out to identify potent compounds that have the potential to bind and block the activity of ZIKV NS5 RNA-dependent RNA polymerase (RdRp). The anti-dengue chemical library was subjected to high-throughput virtual screening and MM/GBSA analysis in order to rate the potential candidates. The top three compounds were then chosen. According to the MM/GBSA analysis, compound 127042987 from the database had the highest binding affinity to the protein with a minimum binding free energy of -77.16 kcal/mole. Compound 127042987 had the most stable RMSD trend and the greatest number of hydrogen bond interactions when these chemical complexes were evaluated further under a 100 ns molecular dynamics simulation. Compound 127042987 displayed the best binding free energy (GBind) of -96.50 kcal/mol, surpassing the native ligand binding energy (-66.17 kcal/mole). Thereafter, an MM/GBSA binding free energy study was conducted to validate the stability of selected chemical complexes. Overall, this study illustrated that compound 127042987 showed preferred binding free energies, suggesting a possible inhibitory mechanism against ZIKV-RdRp. As per this study, it was proposed that compound 127042987 could be used as a therapeutic option to prevent Zika virus infection. These compounds need to be tested in experiments for further validation.

Exploration of Microbially Derived Natural Compounds against Monkeypox Virus as Viral Core Cysteine Proteinase Inhibitors.

Monkeypox virus (MPXV) is a member of the Orthopoxvirus genus and the Poxviridae family, which instigated a rising epidemic called monkeypox disease. Proteinases are majorly engaged in viral propagation by catalyzing the cleavage of precursor polyproteins. Therefore, proteinase is essential for monkeypox and a critical drug target. In this study, high-throughput virtual screening (HTVS) and molecular dynamics simulation were applied to detect the potential natural compounds against the proteinase of the monkeypox virus. Here, 32,552 natural products were screened, and the top five compounds were selected after implementing the HTVS and molecular docking protocols in series. Gallicynoic Acid F showed the minimum binding score of -10.56 kcal/mole in the extra precision scoring method, which reflected the highest binding with the protein. The top five compounds showed binding scores ≤-8.98 kcal/mole. These compound complexes were tested under 100 ns molecular dynamics simulation, and Vaccinol M showed the most stable and consistent RMSD trend in the range of 2 Å to 3 Å. Later, MM/GBSA binding free energy and principal component analysis were performed on the top five compounds to validate the stability of selected compound complexes. Moreover, the ligands Gallicynoic Acid F and H2-Erythro-Neopterin showed the lowest binding free energies of -61.42 kcal/mol and -61.09 kcal/mol, respectively. Compared to the native ligand TTP-6171 (ΔGBind = -53.86 kcal/mol), these two compounds showed preferable binding free energy, suggesting inhibitory application against MPXV proteinase. This study proposed natural molecules as a therapeutic solution to control monkeypox disease.

Computational assessment of Withania somnifera phytomolecules as putative inhibitors of Mycobacterium tuberculosis CTP synthase PyrG.

Genome evolution of Mycobacterium tuberculosis (Mtb) produces new strains resistant to various pre-existing anti-tubercular drugs. Hence, there is an urgent need to explore potent compounds with the most negligible side effects and effective Mtb inhibition. Mtb PyrG (CTP synthase) is a crucial enzyme for the conversion of the uridine triphosphate (UTP) into cytidine triphosphate (CTP) and is essential for the growth of Mtb. Thus, in this study, phytochemicals of Withania somnifera (W. somnifera) were screened to find the potential inhibitors against Mtb PyrG. Molecular docking resulted in the identification of quercetin 3-rutinoside-7-glucoside, rutin, chlorogenic acid and isochlorogenic acid C with a substantial docking score (from -12.6 to -10.8 kcal/mol) contributed by significant intermolecular interactions. Furthermore, 100 ns molecular dynamics simulation, ADME analysis and free binding energy calculations support the stability of docked complexes and drug-likeness for selected compounds, respectively. Collectively, these findings suggest that phytochemicals present in W. somnifera can be considered for further evaluation against Mtb in a series of in vitro and in vivo models.Communicated by Ramaswamy H. Sarma.

Repositioning of anti-dengue compounds against SARS-CoV-2 as viral polyprotein processing inhibitor.

A therapy for COVID-19 (Coronavirus Disease 19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) remains elusive due to the lack of an effective antiviral therapeutic molecule. The SARS-CoV-2 main protease (Mpro), which plays a vital role in the viral life cycle, is one of the most studied and validated drug targets. In Several prior studies, numerous possible chemical entities were proposed as potential Mpro inhibitors; however, most failed at various stages of drug discovery. Repositioning of existing antiviral compounds accelerates the discovery and development of potent therapeutic molecules. Hence, this study examines the applicability of anti-dengue compounds against the substrate binding site of Mpro for disrupting its polyprotein processing mechanism. An in-silico structure-based virtual screening approach is applied to screen 330 experimentally validated anti-dengue compounds to determine their affinity to the substrate binding site of Mpro. This study identified the top five compounds (CHEMBL1940602, CHEMBL2036486, CHEMBL3628485, CHEMBL200972, CHEMBL2036488) that showed a high affinity to Mpro with a docking score > -10.0 kcal/mol. The best-docked pose of these compounds with Mpro was subjected to 100 ns molecular dynamic (MD) simulation followed by MM/GBSA binding energy. This showed the maximum stability and comparable ΔG binding energy against the reference compound (X77 inhibitor). Overall, we repurposed the reported anti-dengue compounds against SARS-CoV-2-Mpro to impede its polyprotein processing for inhibiting SARS-CoV-2 infection.

Identification of Antiviral Compounds against Monkeypox Virus Profilin-like Protein A42R from Plantago lanceolata.

Infections caused by the monkeypox virus (MPXV) have continued to be transmitted significantly in recent years. However, understanding the transmission mechanism, risk factors, and consequences of infection are still limited. Structure-based drug design for MPXV is at an early stage due to the availability of protein structures that have been determined experimentally. However, the structure of the A42R profilin-like protein of MPXV has been solved and submitted to the structure database. This study illustrated an in silico structure-based approach to identify the potential hit compound against A42R of MPXV. Here, 65 Plantago lanceolata compounds were computationally screened against A42R of MPXV. Virtual screening identified top five hits (i) Luteolin 7,3'-Diglucuronide (PubChem ID: 44258091), (ii) Luteolin 7-Glucuronide-3'-Glucoside (PubChem ID: 44258090), (iii) Plantagoside (PubChem ID: 174157), (iv) Narcissoside (PubChem ID: 5481663), and (v) (AlphaE,8S,9R)-N-(3,4-Dihydroxyphenethyl)-8-[(3,4-Dihydroxyphenethyl)Carbamoyl]-9-(1,3-Benzodioxole-5-Yl)-3aalpha,7aalpha-Ethano-1,3-Benzodioxole-5-Acrylamide (PubChem ID: 101131595), with binding energy <−9.0 kcal/mol that was further validated by re-docking and molecular dynamic (MD) simulation. Interaction analysis of re-docked poses confirmed the binding of these top hits to the A42R protein as reported in the reference compound, including active residues ARG114, ARG115, and ARG119. Further, MD simulation and post-simulation analysis support Plantagoside and Narcissoside for substantial stability in the binding pocket of viral protein contributed by hydrogen and hydrophobic interactions. The compounds can be considered for further optimisation and in vitro experimental validation for anti-monkeypox drug development.

Glycosylated Flavonoid Compounds as Potent CYP121 Inhibitors of Mycobacterium tuberculosis.

Due to the concerning rise in the number of multiple- and prolonged-drug-resistant (MDR and XDR) Mycobacterium tuberculosis (Mtb) strains, unprecedented demand has been created to design and develop novel therapeutic drugs with higher efficacy and safety. In this study, with a focused view on implementing an in silico drug design pipeline, a diverse set of glycosylated flavonoids were screened against the Mtb cytochrome-P450 enzyme 121 (CYP121), which is established as an approved drug target for the treatment of Mtb infection. A total of 148 glycosylated flavonoids were screened using structure-based virtual screening against the crystallized ligand, i.e., the L44 inhibitor, binding pocket in the Mtb CYP121 protein. Following this, only the top six compounds with the highest binding scores (kcal/mol) were considered for further intermolecular interaction and dynamic stability using 100 ns classical molecular dynamics simulation. These results suggested a considerable number of hydrogen and hydrophobic interactions and thermodynamic stability in comparison to the reference complex, i.e., the CYP121-L44 inhibitor. Furthermore, binding free energy via the MMGBSA method conducted on the last 10 ns interval of MD simulation trajectories revealed the substantial affinity of glycosylated compounds with Mtb CYP121 protein against reference complex. Notably, both the docked poses and residual energy decomposition via the MMGBSA method demonstrated the essential role of active residues in the interactions with glycosylated compounds by comparison with the reference complex. Collectively, this study demonstrates the viability of these screened glycosylated flavonoids as potential inhibitors of Mtb CYP121 for further experimental validation to develop a therapy for the treatment of drug-resistant Mtb strains.

Pharmacophore-Model-Based Drug Repurposing for the Identification of the Potential Inhibitors Targeting the Allosteric Site in Dengue Virus NS5 RNA-Dependent RNA Polymerase.

Dengue virus (DENV) is the causative agent of DENV infection. To tackle DENV infection, the development of therapeutic molecules as direct-acting antivirals (DAAs) has been demonstrated as a truly effective approach. Among various DENV drug targets, non-structural protein 5 (NS5)-a highly conserved protein among the family Flaviviridae-carries the RNA-dependent RNA polymerase (DENVRdRp) domain at the C-terminal, and its "N-pocket" allosteric site is widely considered for anti-DENV drug development. Therefore, in this study, we developed a pharmacophore model by utilising 41 known inhibitors of the DENVRdRp domain, and performed model screening against the FDA's approved drug database for drug repurposing against DENVRdRp. Herein, drugs complying with the pharmacophore hypothesis were further processed through standard-precision (SP) and extra-precision (XP) docking scores (DSs) and binding pose refinement based on MM/GBSA binding energy (BE) calculations. This resulted in the identification of four potential potent drugs: (i) desmopressin (DS: -10.52, BE: -69.77 kcal/mol), (ii) rutin (DS: -13.43, BE: -67.06 kcal/mol), (iii) lypressin (DS: -9.84, BE: -67.65 kcal/mol), and (iv) lanreotide (DS: -8.72, BE: -64.7 kcal/mol). The selected drugs exhibited relevant interactions with the allosteric N-pocket of DENVRdRp, including priming-loop and entry-point residues (i.e., R729, R737, K800, and E802). Furthermore, 100 ns explicit-solvent molecular dynamics simulations and end-point binding free energy assessments support the considerable stability and free energy of the selected drugs in the targeted allosteric pocket of DENVRdRp. Hence, these four drugs, repurposed as potent inhibitors of the allosteric site of DENVRdRp, are recommended for further validation using experimental assays.

Viral informatics: bioinformatics-based solution for managing viral infections.

Several new viral infections have emerged in the human population and establishing as global pandemics. With advancements in translation research, the scientific community has developed potential therapeutics to eradicate or control certain viral infections, such as smallpox and polio, responsible for billions of disabilities and deaths in the past. Unfortunately, some viral infections, such as dengue virus (DENV) and human immunodeficiency virus-1 (HIV-1), are still prevailing due to a lack of specific therapeutics, while new pathogenic viral strains or variants are emerging because of high genetic recombination or cross-species transmission. Consequently, to combat the emerging viral infections, bioinformatics-based potential strategies have been developed for viral characterization and developing new effective therapeutics for their eradication or management. This review attempts to provide a single platform for the available wide range of bioinformatics-based approaches, including bioinformatics methods for the identification and management of emerging or evolved viral strains, genome analysis concerning the pathogenicity and epidemiological analysis, computational methods for designing the viral therapeutics, and consolidated information in the form of databases against the known pathogenic viruses. This enriched review of the generally applicable viral informatics approaches aims to provide an overview of available resources capable of carrying out the desired task and may be utilized to expand additional strategies to improve the quality of translation viral informatics research.

Discovery of Small Molecules from Echinacea angustifolia Targeting RNA-Dependent RNA Polymerase of Japanese Encephalitis Virus.

The Japanese encephalitis virus (JEV), a mosquito-borne flavivirus that causes viral encephalitis leading to neural damage, is a major threat in most Asian countries. The RNA-dependent RNA polymerase (RdRp) present in the viral genome is the key component for genome replication, making it an attractive target for antiviral drug development. In this study, the natural products from Echinacea angustifolia were retrieved for structure-based virtual screening against JEV-RdRp. The top six compounds (Echinacoside, Echinacin, Rutin, Cynaroside, Quercetagetin 7-glucoside, and Kaempferol-3-glucoside) were obtained based on the highest negative docking score, ADMET (absorption, distribution, metabolism, excretion, and toxicity), and molecular interaction. The computational analysis of these selected compounds against the co-crystallized ligands, i.e., ATP and GTP, were performed. Further, 100 ns molecular dynamic simulation and post-free binding energy calculation of all the selected compounds complexed with JEV-RdRP were performed to check the stability of the complexes. The obtained results showed considerable stability and intermolecular interaction with native ligand-binding site residues of JEV-RdRp. Hence, selected natural compounds are admissible inhibitors of JEV-RdRp protein and can be considered for future antiviral drug development studies.

Molecular pathogenesis of Japanese encephalitis and possible therapeutic strategies.

Japanese encephalitis virus (JEV), a single-stranded, enveloped RNA virus, is a health concern across Asian countries, associated with severe neurological disorders, especially in children. Primarily, pigs, bats, and birds are the natural hosts for JEV, but humans are infected incidentally. JEV requires a few host proteins for its entry and replication inside the mammalian host cell. The endoplasmic reticulum (ER) plays a significant role in JEV genome replication and assembly. During this process, the ER undergoes stress due to its remodelling and accumulation of viral particles and unfolded proteins, leading to an unfolded protein response (UPR). Here, we review the overall strategy used by JEV to infect the host cell and various cytopathic effects caused by JEV infection. We also highlight the role of JEV structural proteins (SPs) and non-structural proteins (NSPs) at various stages of the JEV life cycle that are involved in up- and downregulation of different host proteins and are potentially relevant for developing efficient therapeutic drugs.