Investigation of natural compounds as methyltransferase inhibitors against dengue virus: an in silico approach.

The global challenge posed by Dengue virus (DENV) infection persists, exacerbated by the absence of specific antiviral therapies. The viral methyltransferase (MTase) enzyme, crucial for viral RNA methylation and immune system evasion, has emerged as a promising drug target for combating Dengue fever. In this study, a comprehensive exploration of natural compounds derived from the COCONUT database was conducted, selecting 224 compounds based on their structural similarity to the native substrate of the MTase enzyme, S-adenosyl-L-methionine (SAM). Employing virtual screening techniques, four natural compounds (CNP0307160, CNP0082902, CNP0449158, and CNP0296775) with acceptable docking scores were selected for further re-docking after geometry optimization by the DFT method. Re-docking analyses unveiled significant interactions, including hydrogen bonds and hydrophobic interactions, between these selected ligands and the MTase protein. To gain deeper insights into the dynamic stability of these complexes, we conducted molecular dynamics simulations which showed lower RMSD values for CNP0307160, CNP0082902, and CNP0296775 when compared to the reference molecule. Furthermore, we assessed the structural and dynamic stability of the protein-ligand complexes through free binding energy calculations and Principal Component Analysis (PCA) of the simulation trajectories. In these analyses, the CNP0296775 compound exhibited promising results compared to the other three compounds. The cumulative findings of these investigations underscore the potential of CNP0296775 as a strong inhibitor of DENV MTase, thus offering a promising starting point for its further experimental validation and optimization.Communicated by Ramaswamy H. Sarma.

Repurposing Anti-Dengue Compounds against Monkeypox Virus Targeting Core Cysteine Protease.

The monkeypox virus (MPXV) is an enveloped, double-stranded DNA virus belonging to the genus Orthopox viruses. In recent years, the virus has spread to countries where it was previously unknown, turning it into a worldwide emergency for public health. This study employs a structural-based drug design approach to identify potential inhibitors for the core cysteine proteinase of MPXV. During the simulations, the study identified two potential inhibitors, compound CHEMBL32926 and compound CHEMBL4861364, demonstrating strong binding affinities and drug-like properties. Their docking scores with the target protein were -10.7 and -10.9 kcal/mol, respectively. This study used ensemble-based protein-ligand docking to account for the binding site conformation variability. By examining how the identified inhibitors interact with the protein, this research sheds light on the workings of the inhibitors' mechanisms of action. Molecular dynamic simulations of protein-ligand complexes showed fluctuations from the initial docked pose, but they confirmed their binding throughout the simulation. The MMGBSA binding free energy calculations for CHEMBL32926 showed a binding free energy range of (-9.25 to -9.65) kcal/mol, while CHEMBL4861364 exhibited a range of (-41.66 to -31.47) kcal/mol. Later, analogues were searched for these compounds with 70% similarity criteria, and their IC50 was predicted using pre-trained machine learning models. This resulted in identifying two similar compounds for each hit with comparable binding affinity for cysteine proteinase. This study's structure-based drug design approach provides a promising strategy for identifying new drugs for treating MPXV infections.

Computer-assisted discovery of safe and effective DprE1/ aaRSs Inhibitors against TB utilizing Drug Repurposing approach.

BACKGROUND: The emergence of various drug-resistant strains of Mycobacterium tuberculosis compelled medicinal chemists to expedite the discovery of novel, safer alternatives to present regimens. Decaprenylphosphoryl-ß-d-ribose 2'-epimerase (DprE1), an essential component of arabinogalactan biosynthesis, has been considered a novel target for developing new inhibitors against Tuberculosis. We aimed to discover DprE1 inhibitors utilizing the drug repurposing approach. METHODS: A structure-based virtual screening of FDA and world-approved drugs database was carried out, and initially, 30 molecules were selected based on their binding affinity. These compounds were further analyzed by molecular docking with extra-precision mode, MMGBSA binding free energy estimation, and prediction of ADMET profile. RESULTS: Based on the docking results and MMGBSA energy values- ZINC000006716957, ZINC000011677911, and ZINC000022448696 were identified to be the top three hit molecules with good binding interactions inside the active site of DprE1. These hit molecules were subjected to molecular dynamics (MD) simulation for a period of 100 ns to study the dynamic nature of the binding complex. MD results were in accordance with molecular docking and MMGBSA analysis showing protein-ligand contacts with key amino acid residues of DprE1. CONCLUSION: Based on their stability throughout the 100 ns simulation, ZINC000011677911 was the best in silico hit with an already known safety profile. This molecule could lead to future optimization and development of new DprE1 inhibitors.