FIG 5.

Sequence alignment of the M^pros from different CoVs. FIPV (GenBank accession no. AY994055) and TGEV (GenBank accession no. FJ755618) are from Alphacoronavirus, SARS-CoV (GenBank accession no. NC_004718) from Betacoronavirus, infectious bronchitis virus (IBV) (GenBank accession no. AY641576) from Gammacoronavirus, and porcine coronavirus HKU15 (GenBank accession no. KM012168) and white-eye coronavirus HKU16 (GenBank accession no. NC_016991) from Deltacoronavirus. The conserved residues that participate in coordinating the Zn²⁺ are labeled by arrows. Sequence alignment was performed with ClustalW and drawn using ESPript3. White letters with red backgrounds show identical residues, and red letters with white backgrounds show conservative variation. Blue arrows indicate residues involved in coordinating Zn²⁺ in FIPV M^pro and are well-conserved in M^pro sequences from multiple species.