Fig. 6.

Relative mutation site analysis with respect to heparin binding to the closed state. Inset table lists the mutations reported as of February 2021 (GISAID-hcov-19 with entropy greater than 0.1). The three peptides constituting the spike trimer are colored red, blue and gray. Heparin mostly interacts with blue peptide in this pose, therefore, all the mutant positions are labelled on the same to avoid confusion. Interestingly most of the mutant locations are away from the heparin binding site which suggests important and highly conserved role of sulfated polysaccharides in the viral invasion as well as usability of heparin as a universal blocker of all the mutant spike variants. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)