Fig. 6.

Mutations associated with the N-terminus domain of SARS-CoV-2 spike protein. (A) Distribution and relative frequency of mutations in the N-terminus amino-acid sequence of SARS-CoV-2 spike protein. Mutation frequency has been calculated based on the number of GISAID strains harboring nonsynonymous mutations/deletions in each amino acid position. (B) Global frequency of mutations in β3-β4, β9-β10 and β14-β15 loop regions calculated as percentages of the total mutations in the SARS-CoV-2 NTD region (aa 1–350). (C) Relative frequency of mutation for indicated loops during early, middle and recent phase of the COVID-19 pandemic.