Fig. 3.

Alignment of amino acids of L protein, VP1 loop I and II, VP2 puff A and B among different cardioviruses. a Alignment of amino acids of L protein. The zinc finger (pink), acidic domain (blue), and Ser/Thr rich domain (brown) was shown. Two mutations in the Ser/Thr rich domain was found in SX1. b, c Alignment of amino acids of VP1 loops and VP2 puffs. Three key resides of VP2 puff B on the viral surface binding to host cells were marked gray and as asterisk. Low homology in VP1 loop II and an alternative residue “T” in VP2 puff B that is vital for sialic acid binding was found