Exploring Structural Mechanism of COVID-19 Treatment with Glutathione as a Potential Peptide Inhibitor to the Main Protease: Molecular Dynamics Simulation and MM/PBSA Free Energy Calculations Study

The 2019-novel coronavirus has unfolded everywhere in the world and obliged a billion human beings in open confinement, whereas many treatments, and vaccines have been proposed towards this pandemic. The main protease (M(pro)) is an attractive drug target due to the fact that it is the essential protein for virus invasion. This research tests in silico the effect of five vitamins towards M(pro), by employing molecular docking (MD), molecular dynamics simulation (MDS) with molecular mechanics–Poisson–Boltzmann surface area (MM–PBSA) studies. To achieve this work, we have applied some software’s as Autodock Vina, Discovery Studio Visualizer, APBS, and GROMACS. The inhibitors used were decided entirely on the basis of their importance in the production of red blood cells that prevent anemia, in lymphocyte immune system responses, in the regulation of reactive oxygen species production, such as tocopherol (vitamin E), thiamine (vitamin B1), pantothenic acid (vitamin B5), pyridoxine (vitamin B6), biotin (vitamin B7), and glutathione (GSH). The best inhibitor pose established at the highest repetition ratio (RR) and the minimal affinity energy value (MEV), then the best selected inhibitor was considered to MDS. The results indicate that GSH is the leading inhibitor model among the other tested vitamins in the active site of M(pro) with a RR value of 94% and MEV of − 5.5 kcal/mol, its RMSD, RMSF, Rg, and hydrogen bonds show stability with M(pro). Furthermore, thiamine, biotin, and tocopherol are viewed as satisfying inhibitors to M(pro), but pyridoxine was observed as the weakest inhibitor. Based on our result, we could recommend the usage of glutathione and vitamin B family as a supportive strategy for feasible remedy of COVID-19 virus.