Emerging genetic diversity of SARS-CoV-2 RNA dependent RNA polymerase (RdRp) alters its B-cell epitopes

The RNA dependent RNA polymerase (RdRp) plays crucial role in virus life cycle by replicating the viral RNA genome. The SARS-CoV-2 is an RNA virus that rapidly spread worldwide and during this process acquired mutations. This study was carried out to identify mutations in RdRp as the SARS-CoV-2 spread in India. We compared the 668 RdRp sequences reported from India with the first reported RdRp sequence from Wuhan, China. Our data revealed that RdRp have acquired sixty mutations among Indian isolates. Our protein modelling study also revealed that several mutants including D833Y, A699S, Y149C and C464F can potentially alter stability and flexibility of RdRp. We also predicted the potential B cell epitopes contributed by RdRp and identified thirty-six linear continuous and twenty-five discontinuous epitopes. Among sixty RdRp mutants identified in this study, 40% of them localises in the B cell epitopes region. Altogether, this study highlights the need to identify and characterize the variations in RdRp to understand the impact of these mutations on SARS-CoV-2.