Fig. 2.

A Schematic representation of the 29.9 kbp-long SARS-CoV-2 genome where the different regions have been highlighted. B The 1273 amino acid long S protein of the SARS-CoV-2 showing different domains with mutations belonging to the delta, delta plus, and mu variants. The black arrows point to the major mutations across the S protein for the B.1.617.2 (Delta) variant, while the red and cyan arrows indicate the exclusive mutations present in the AY.1 (delta plus) and B.1.621 (Mu) variants, respectively. The scale shows the relative position of the amino acids in the S protein. Index: S1 and S2: S protein subunits 1 and 2, NTD: N-terminal domain, RBD: Receptor-binding domain, RBM: Receptor-binding motif, SD1 and SD2: Sub-domains 1 and 2, FP: Fusion peptide, HR1 and HR2: Heptad repeats 1 and 2, TM: Transmembrane domain, CT: Cytoplasmic domain (Color figure online)