Fig. 5.

The critical residues in EK1 can flexibly interact with variable residues in HR1 region of HCoVs mainly through the hydrophilic interaction. a The EK1 peptides in their complex structures with SARS-CoV-2 (α, PDB entry 7C53), SARS-CoV (β, PDB entry 5ZVM), MERS-CoV (γ, PDB entry 5ZVK) and hCoV-229E (δ, PDB entry 5ZUV) are superposed together, shown as ribbon in magentas. The SARS-CoV-2 HR2 trimer is shown as surface and colored according to the residue conservations. b–f The interaction details of EK1 against HR1 in different HCoVs are shown. Important residues are shown in sticks and labeled