catalytic core domain of RNA-dependent RNA polymerase (RdRp) in the subfamily Regressovirinae of positive-sense single-stranded RNA [(+)ssRNA] viruses
This group contains the catalytic core domain of the RdRp of RNA viruses belonging to the subfamily Regressovirinae, family Tombusviridae, order Tolivirales. Dianthovirus is a genus of plant viruses within this subfamily. All the genera in the family Tombusviridae have monopartite (+)ssRNA genomes, except the dianthoviruses which have bipartite (+)ssRNA genomes. The dianthoviruses are distributed worldwide. The genus Dianthovirus is composed of three viruses: Carnation ringspot virus, Red clover necrotic mosaic virus, and Sweet clover necrotic mosaic virus. The amino acid (aa) sequence of dianthovirus RdRp has higher homology with that of the luteoviruses, while the amino acid sequence of dianthovirus coat protein (CP) has high homology with those of the tombusviruses and aureusviruses that belong to the subfamily Procedovirinae. 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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