Fig. 5: Phylogenetic analysis of coronavirus spike C-terminal sequence.

This phylogram was generated from the alignment of five C-terminal residues in the spike protein. This penta-residue spike sequence is shown in italics to the right of each coronavirus. The residues in the dibasic motif are underlined. An acidic Asp is seen at the C-terminus of the spike proteins of only those coronaviruses that lack a dibasic motif.