catalytic core domain of RNA-dependent RNA polymerase (RdRp) in the family Eunroniviridae of positive-sense single-stranded RNA [(+)ssRNA] viruses
This group contains the catalytic core domain of RdRp of RNA viruses belonging to the family Eunroniviridae, order Nidovirales. Member viruses have a viral envelope and (+)ssRNA genome. Eunroniviridae is a closely related family of crustacean nidoviruses, within the suborder Ronidovirineae, which also includes the family Roniviridae. Ronidovirineae, named "rod-shaped nidovirus", is 150-200 nm long and approximately 60 nm thick. There are 3 viral species in the Euroniviridae family, all of which have been detected in crustaceans. The structure of Euroniviridae RdRp contains a RdRp domain as well as a large N-terminal extension that adopts a nidovirus RdRp-associated nucleotidyltransferase (NiRAN) architecture. 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.",