Fig. 3
From: Probable human origin of the SARS-CoV-2 polybasic furin cleavage motif
PRRA-like insertion along the SARS-CoV-2 spike glycoprotein. PRRA-like insertion positions in the SARS-CoV-2 spike glycoprotein. With coordinate based on SARS-CoV reference sequence [14], boxes on the top show the sequence positions of the PRRA-like insertions. The SARS-CoV-2 spike glycoprotein structural domains and cleavage sites are indicated. Protein length: 1273. At the bottom the S1 subunit and S2 subunit in each spike glycoprotein monomer are indicated. The coordinates of some of the domains are in parentheses. Acronyms: S1, subunit 1; S2, subunit 2; SP, signal peptide; NTD. N-terminal domain; RBD, receptor binding domain; SD1, subdomain 1; SD2, subdomain 2; FP, fusion peptide; HR1, heptad repeat 1; HR2, heptad repeat 2; TM, transmembrane region; IC, inracellular domain. Cleavage sites: S1/S2, R685/S686, by host (human) furin, paired basic amino acid cleaving enzyme (FURIN); S2’, R815/S816, by host transmembrane serine protease 2 (TMPRSS2) orcathepsin L (CTSL). The figure has been created based on data from [19,20,21]