RNA-dependent RNA polymerase (RdRp) in the genus Dicipivirus of positive-sense single-stranded RNA [(+)ssRNA] viruses, within the family Picornaviridae
This group contains the RdRp of RNA viruses belonging to the Dicipivirus genus within the family Picornaviridae, order Picornavirales. The Dicipivirus contains viruses with (+)ssRNA genomes that produce nonenveloped virions. The genus Dicipivirus contains two species, Cadicivirus A and Cadicivirus B. A new dicipivirus has been found in hedgehogs. 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",