catalytic core domain of RNA-dependent RNA polymerase (RdRp) in the genus Fipivirus of positive-sense single-stranded RNA [(+)ssRNA] viruses, within the family Picornaviridae
This group contains the catalytic core domain of the RdRp of RNA viruses belonging to the Fipivirus genus within the family Picornaviridae, order Picornavirales. The Fipivirus contains viruses with (+)ssRNA genomes that produce nonenveloped virions. This genus contains five species: Fipivirus A (Wuhan sharpbelly picornavirus 2), Fipivirus B (Wuhan sharpbelly picornavirus 3), Fipivirus C (Wenling crossorhombus picornavirus), Fipivirus D (Wenling jack mackerels picornavirus) and Fipivirus E (Wenling banjofish picornavirus 1). All contain viruses from fish. RdRps catalyze RNA template-dependent formation of phosphodiester bonds between ribonucleotides in the presence of divalent metal ions. The initiation of synthesis occurs at the 3'-end of the template in a VPg-dependent manner, and proceeds in the direction of 5'-3'. The active sites of RdRps are highly conserved in different species of picornaviruses. 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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