Analysis of Whole Genome Sequences and Homology Modelling of a 3-C Like Peptidase and a Non-Structural Protein of the Novel Coronavirus COVID-19 Shows Protein Ligand Interaction with an Aza-Peptide and a Noncovalent Lead Inhibitor with Possible Antiviral Properties

The family of viruses belonging to Coronaviridae mainly consist of virulent pathogens that have a zoonotic property, Severe Respiratory Syndrome (SARS-CoV) and Middle East Respiratory Syndrome (MERS-CoV) of this family have emerged before and now the Novel COVID-19 has emerged in China. Characterization of spike glycoproteins, polyproteins and other viral proteins from viruses are important for vaccine development. Homology modelling of these proteins with known templates offers the opportunity to discover ligand binding sites and possible antiviral properties of these protein ligand complexes. Any information emerging from these protein models can be used for vaccine development. In this study we did a complete bioinformatic analysis, sequence alignment, comparison of multiple sequences and homology modelling of the Novel COVID-19 whole genome sequences, the spike protein and the polyproteins for homology with known proteins, we also analysed receptor binding sites in these models for possible vaccine development. Our results showed that the tertiary structure of the polyprotein isolate COVID-19 _HKU-SZ-001_2020 had 98.94 percent identity with SARS-Coronavirus NSP12 bound to NSP7 and NSP8 co-factors. Our results indicate that a part of the viral genome (residues 254 to 13480 in Frame 2 with 4409 amino acids) of the Novel COVID-19 virus isolate Wuhan-Hu-1 (Genbank Accession Number MN908947.3) when modelled with template 2a5i of the PDB database had 96 percent identity with a 3C like peptidase of SARS-CoV which has ability to bind with Aza-Peptide Epoxide (APE) which is known for irreversible inhibition of SARS-CoV main peptidase. The part of the genome when modelled with template 3e9s of the PDB database had 82 percent identity with a papain-like protease/deubiquitinase which when complexed with ligand GRL0617 acts as inhibitor which can block SARS-CoV replication. It is possible that these viral inhibiters can be used for vaccine development for the Novel COVID-19.