ART4 and influenza: The second group of structurally-similar envelope proteins comprises glycoproteins belonging to negative-strand ssRNA viruses (Asian influenza, a subtype of influenza A, influenza B virus strain B/Memphis/13/03, influenza C virus strain C/Johannesburg/1/66) and to betacoronavirus of the Coronaviridae family with positive-strand ssRNA genome (Table 2 and Figure 4C).