catalytic core domain of RNA-dependent RNA polymerase (RdRp) in the family Leviviridae of positive-sense single-stranded RNA [(+)ssRNA] viruses
This group contains the catalytic core domain of RdRp of RNA viruses belonging to the family Leviviridae, order Levivirales. Leviviridae is a family of (+)ssRNA viruses which are highly antigenic and are abundantly present in sewage, waste water, animal and human feces. Within this family two genera can be distinguished, Levivirus and Allolevivirus. Members of the family Leviviridae that propagate in Escherichia coli infect by adsorption to the sides of F(ertility) pili. This event leads to cleavage of the A-protein and release of the RNA from the virion into the bacterium. The infecting RNA encodes a replicase, which assembles with three host proteins, ribosomal protein S1 and translation elongation factors EF-Tu and EF-Ts, to form the active RNA polymerase. Leviviruses not only infect enterobacteria, but also species of the genera Caulobacter, Pseudomonas, and Acinetobacter, and probably many other Gram-negative bacteria. 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.",