catalytic core domain of RNA-dependent RNA polymerase (RdRp) in the family Picornaviridae of positive-sense single-stranded RNA [(+)ssRNA] viruses
This group contains the catalytic core domain of RdRp of RNA viruses belonging to the family Picornaviridae, order Picornavirales. The Picornaviridae family consists of small, icosahedral viruses with (+)ssRNA genomes. Characteristic features of all members of the family Picornaviridae are three capsid proteins with beta-barrel folding, polyprotein processing by virus-encoded cysteine proteinase(s), and replication by an RdRp with a YGDD sequence motif. The family Picornaviridae comprises 68 genera containing 158 species, but many viruses are presently awaiting classification. The established genera of the family include: Aphthovirus, Avisivirus, Crohivirus, Enterovirus, Teschovirus, Cardiovirus, Erbovirus, Kobuvirus, Hepatovirus, Parechovirus, Aquamavirus, Avihepatovirus, Avisivirus, Cosavirus, Dicipivirus, Fipivirus, Gallivirus, Hunnivirus, Kunsagivirus, Limnipivirus, Megrivirus, Mischivirus, Mosavirus, Oscivirus, Pasivirus, Passerivirus, Rabovirus, Rosavirus, Sakobuvirus, Salivirus, Sapelovirus, Senecavirus, Sicinivirus, and Tremovirus. The Picornaviridae contains many important human and animal pathogens including enteroviruses (such as poliovirus, enterovirus, coxsackievirus, and rhinovirus), cardioviruses (such as encephalomyocarditis virus and Theiler's virus), hepatitis A virus and foot-and-mouth disease virus. Infection with various picornaviruses may cause encephalitis, febrile rash illnesses (hand-foot-and-mouth disease), aseptic meningitis, hepatitis, conjunctivitis, herpangina, myositis and myocarditis, and the common cold. The RdRp domain displays a right hand with three functional subdomains, called fingers, palm, and thumb. All RdRps contain conserved polymerase motifs (A-G), located in the palm (A-E motifs) and finger (F-G) subdomains. All these motifs have been implicated in RdRp fidelity such as processes of correct incorporation and reorganization of nucleotides.
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