Figure 2: S protein of SARS-CoV-2 with a focus on favourable putative site
S protein consists of S1 subunit (N-terminal domain (NTD) and receptor binding domain (RBD)) and S2 subunit (fusion peptide (FP), internal fusion peptide (IFP), heptad repeat 1/2 (HR1/2), and transmembrane domain (TM)) along with signal peptide (SP). Cleavage sites of SP, S1/S2 and S2′ are indicated by arrows. The figure is modified and adapted from Coutard et al .