catalytic core domain of RNA-dependent RNA polymerase (RdRp) in the family Flaviviridae of positive-sense single-stranded RNA (+ssRNA) viruses
This group contains the catalytic core domain of RdRp of RNA viruses belonging to the family Flaviviridae, order Amarillovirales. Flaviviridae, is a family of small, enveloped viruses with RNA genomes of 9-13 kb. Most infect mammals and birds. Many flaviviruses are host-specific and pathogenic, such as hepatitis C virus in the genus Hepacivirus. The majority of known members in the genus Flavivirus are arthropod borne, and many are important human and veterinary pathogens (e.g., yellow fever virus, dengue virus). Virions are typically spherical in shape with a lipid envelope. Virions have a single, small, basic capsid (C) protein and two (genera Flavivirus, Hepacivirus and Pegivirus) or three (genus Pestivirus) envelope proteins. They contain a single, long ORF flanked by 5'- and 3'-terminal non-coding regions, which form specific secondary structures required for genome replication and translation. Translational initiation of genomic RNA is cap dependent in the case of members of the genus Flavivirus. 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.