RNA-dependent RNA polymerase (RdRp) in the Aphthovirus genus of positive-sense single-stranded RNA [(+)ssRNA] viruses
This group contains the RdRp of RNA viruses belonging to the Aphthovirus genus within the family Picornaviridae, order Picornavirales. Member viruses have a (+)ssRNA genome. This genus includes species such as bovine rhinitis A virus, bovine rhinitis B virus, equine rhinitis A virus, and food-and-mouth disease virus (FMDV). Aphthoviruses primarily infect via the upper respiratory tract. FMDV infects mainly cloven-hoofed animals, but has been isolated from at least 70 species of mammals. Aphthoviruses are non-enveloped and have an icosahedral capsid with a diameter of around 27 to 30 nm. The assembled viral capsid contains a single copy of the RNA genome and 60 copies of the four viral capsid proteins VP1, VP2, VP3, and VP4. 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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