Multiple sequence alignment of S fragment (RBD) with SARS CoV-related and other coronaviruses/spike glycoproteins. A) The table shows 13 amino acid residues in the region of S RBD (319–518) which have sequence variations as identified from the multiple sequence alignment of S RBD with 19 SARS CoV-related sequences (97–99% identities with S RBD) using BLAST. B) Multiple sequence alignment of S RBD and 7 other related proteins from different organisms which share 20–35% identities: bovine coronavirus (BCoV, 327–622), canine respiratory coronavirus (CCoV, 327–622), human coronavirus (OC43, 331–612), equine coronavirus (ECoV, 327–622), porcine hemagglutinating encephalomyelitis virus (PHEV, 327–608), rat sialodacryoadenitis coronavirus (RtCoV, 325–610) and murine hepatitis virus (MHV, 325–611). Dark and gray colors indicate the identity and similarity of residues aligned. Arrowheads on the S RBD sequence show the 13 sites, which are found to have sequence variations. C) The phylogram tree is shown with distances along the protein names and note that S RBD has the highest distance. Multiple sequence alignment and phylogram were constructed using ClustalW program.