An immunoinformatics approach to study the epitopes contributed by Nsp13 of SARS-CoV-2

The on-going coronavirus disease-19 (COVID-19) pandemic caused by SARS-CoV-2 has infected hundreds of millions of people and killed more than two million people worldwide. Currently, there are no effective drugs available for treating SARS-CoV-2 infections; however, vaccines are now being administered worldwide to control this virus. In this study, we have studied SARS-CoV-2 helicase, Nsp13, which is critical for viral replication. We compared the Nsp13 sequences reported from India with the first reported sequence from Wuhan province, China to identify and characterize the mutations occurring in this protein. To correlate the functional impact of these mutations, we characterised the most prominent B cell and T cell epitopes contributed by Nsp13. Our data revealed twenty-one epitopes, which exhibited high antigenicity, stability and interactions with MHC class-I and class-II molecules. Subsequently, the physiochemical properties of these epitopes were also analysed. Furthermore, several of these Nsp13 epitopes harbour mutations, which were further characterised by secondary structure and per-residue disorderness, stability and dynamicity predictions. Altogether, we report the candidate epitopes of Nsp13 that may help the scientific community to understand the evolution of SARS-CoV-2 variants and their probable implications.