FIG 1.
PEDV spike protein. (A) Domain structure of PEDV spike. It contains a receptor-binding S1 subunit, a membrane fusion S2 subunit, a single-pass transmembrane anchor (TM), and a short intracellular tail (IC). S1 contains an N-terminal domain (S1-NTD) and a C-terminal domain (S1-CTD). S2 contains the fusion peptide (FP), heptad repeat 1 (HR1), and heptad repeat 2 (HR2), all of which are essential structural elements for the membrane fusion process. (B) Amino acid sequence identities between PEDV spike and the spikes from TGEV, BtCoV/512/2005, and HCoV-NL63 in different regions. GenBank accession numbers are AGO58924.1 for PEDV spike, CAA29175.1 for TGEV spike, ABG47078.1 for BtCoV/512/2005 spike, and AAS58177.1 for HCoV-NL63 spike.