Mutation Hot Spots in Spike Protein of COVID-19

Spike protein of Coronaviruses help in receptor binding and virus entry into the host cells. While spike protein helps in receptor mediated virus entry, it is also extremely important as an immunogen as it is the most accessible part of the viral architecture. SARS-CoV2 or COVID 19 has four different structural proteins, N (nucleocapsid), M (membrane), E (envelope) and S (spike). Although all these proteins are the part of virus structure, only E, M and S are exposed towards the outer surface of the virus particle. S protein forms a knob like structure protruding outwards beyond the other structural proteins. It forms homotrimers containing an S1 and S2 as monomers and together they form the viral spikes. Mutations in structural proteins of virus play crucial role in viral virulence by determining generation of antibody escape variants and cellular tropism. In this paper we have performed in depth analyses of spike protein sequence from various parts of the world and tried to correlate the data with the current situation of virulent nature of this virus in certain parts of the world much more as compared to others. Here, we have focussed on the isolates from the North America and have pointed out three major hot spots of mutations in the S1 subunit.