Fully relativistic study of polyatomic closed shell E121X3 (X = F, Cl, Br) molecules: effects of Gaunt interaction, relativistic effects and advantages of an exact-two component (X2C) hamiltonian.

In this study, all electron relativistic calculations with 4-component Dirac-Coulomb-Breit (DCB), 4-component Dirac-Coulomb (DC), Dyall's spin-free Dirac-Coulomb (SFDC), exact two-component (X2C) and Levy-Leblond non-relativistic hamiltonians calculations were performed in polyatomic closed shell E121X3 (X = F, Cl, Br) within density functional theory (DFT) with hybrid functional B3LYP, where E121 is the superheavy element (SHE) with Z = 121. The aims of this study were to investigate relativistic effects in polyatomic E121X3 (X = F, Cl, Br) and verify the importance of Gaunt effects. The results demonstrate that although the effect of Gaunt interaction is small on change equilibrium bond lengths and bonding, it is important to obtain reliable vibrational frequencies. Moreover, it is possible to use the X2C spin-free hamiltonian to lower computational costs in a fully relativistic investigation of polyatomics including the SHE of the 8th period. Finally, a comparison between electron localization function (ELF) analysis and Mulliken population analysis suggests bonding similarity between LaBr3 and E121Br3. Graphical Abstract Relativistic 4-Component calculations suggest bond similarity between LaBr3 and E121Br3.

Virtual Screening and Molecular Dynamics Simulations from a Bank of Molecules of the Amazon Region Against Functional NS3-4A Protease-Helicase Enzyme of Hepatitis C Virus.

Hepatitis C virus (HCV) infection is a disease that affects approximately 3% of the global population and requires new therapeutic agents without the inconvenience associated with current anti-HCV treatment. This paper reports on a study of a virtual screening and a molecular dynamics simulation of compounds derived from natural products from the Amazon region that are potentially effective against the NS3-4A enzyme of HCV, which plays an important role in the replication process of this virus. According to the results of the molecular docking calculations and subsequent consensual analysis, the best scored compounds showed interactions between hydrogen and residues of the catalytic triad as well as interactions with residues that guide ligands to the active site of the enzyme. They also showed stability in the molecular dynamics simulation, as the structures preserved important interactions at the active site of the enzyme. The root mean square deviation (RMSD) values were stabilized at the end of the simulation time. Such compounds are considered promising as novel therapies against HCV.