CAUTION: This alignment is very weak. It can not be generated by clustalw. If a representative set is used for a seed, many so-called members are not recognised. The family should probably be split up into sub-families. Capsid proteins of picornaviruses. Picornaviruses are non-enveloped plus-strand ssRNA animal viruses with icosahedral capsids. They include rhinovirus (common cold) and poliovirus. Common structure is an 8-stranded beta sandwich. Variations (one or two extra strands) occur.