Receptor-Based Pharmacophore Modelling of a series of ligands used as inhibitors of the SARS-CoV-2 virus by complementary theoretical approaches, molecular docking, and reactivity descriptors. [version 1; peer review: 2 approved with reservations]

Background: A coronavirus identified in 2019, SARS- CoV- 2, has caused a pandemic of respiratory illness, called COVID- 19. Most people with COVID-19 experience mild to moderate symptoms and recover without the need for special treatments. The SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) plays a crucial role in the viral life cycle. The active site of the RdRp is a very accessible region, so targeting this region to study the inhibition of viral replication may be an effective therapeutic approach. For this reason, this study has selected and analysed a series of ligands used as SARS-CoV-2 virus inhibitors, namely: the Zidovudine, Tromantadine, Pyramidine, Oseltamivir, Hydroxychoroquine, Cobicistat, Doravirine (Pifeltro), Dolutegravir, Boceprevir, Indinavir, Truvada, Trizivir, Trifluridine, Sofosbuvir and Zalcitabine. Methods: These ligands were analyzed using molecular docking, Receptor-Based Pharmacophore Modelling. On the other hand, these outcomes were supported with chemical reactivity indices defined within a conceptual density functional theory framework. Results: The results show the conformations with the highest root-mean-square deviation (RMSD), have π-π stacking interaction with residue LEU141, GLN189, GLU166 and GLY143, HIE41, among others. Also was development an electrostatic potential comparison using the global and local reactivity indices. Conclusions: These studies allow the identification of the main stabilizing interactions using the crystal structure of SARS-CoV-2 RNA-dependent RNA polymerase. In this order of ideas, this study provides new insights into these ligands that can be used in the design of new COVID-19 treatments. The studies allowed us to find an explanation supported in the Density Functional Theory about the chemical reactivity and the stabilization in the active site of the ligands.