Figure 2.

Comparison of S2′ cleavage sites in coronavirus spike structures

S2′ cleavage occurs after a coronavirus conserved arginine residue. This position is preceded by a protein loop and an N-linked glycan, which appear to occlude this cleavage site in the prefusion conformation. Structures used for comparison include spikes from HuCoV-NL63 (PDB: 5SZS; Walls et al., 2016b), porcine deltacoronavirus (PDB: 6BFU; Xiong et al., 2018), MERS-CoV (PDB: 5W9I; Pallesen et al., 2017), SARS-CoV (PDB: 6CRV; Kirchdoerfer et al., 2018), and infectious bronchitis virus (PDB: 6CV0; Shang et al., 2018a).