3CLpro, 3C-like proteinase; COVID-19; COVID-19, coronavirus disease 2019; DOPE, discrete optimized protein energy; FDA approved antiviral drugs; FDA, Food and Drug Administration; GRAVY, grand average of hydropathicity; GZR, Grazoprevir; GpppA, Guanosine-P3-adenosine-5',5'-triphosphate; Homology modelling; MERS-CoV, Middle East respiratory syndrome coronavirus; Molecular docking; N7-MTase, S-adenosyl methionine (SAM)-dependent (guanine-N7) methyltransferase; Nsp13 helicase; Nsp14; Nsps, non-structural proteins; PDB, protein data bank; PLpro, papain-like proteinase; PTV, Paritaprevir; RMSD, root mean square deviation; RTC, replication-transcription complex; RdRp, RNA-dependent RNA polymerase; SAH, S-adenosyl homocysteine; SARS-CoV, severe acute respiratory syndrome coronavirus; SARS-CoV-2; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; SAVES, Structure Analysis and Verification Server; SF, Sinefungin; SMV, Simeprevir; TMHs, transmembrane helices; ZBD, zinc binding domain