RNA-dependent RNA polymerase (Viral) (RdRp)

The viral replicase, most specifically the RNA-dependent RNA polymerase (RdRp), is the enzyme at the core of viral RNA replication complexes found in RNA viruses. These complexes are responsible for synthesizing both genomic and subgenomic RNA during viral replication cycles. The replicase structure often adopts a "cupped right hand" fold with palm, thumb, and fingers domains. In many viruses, such as coronaviruses, the replicase complex contains both the core polymerase and multiple viral and sometimes host co-factors required for processivity, RNA capping, and error correction. Because of its essential role in viral reproduction, the replicase and especially its polymerase activity are prime drug targets; numerous licensed and experimental antiviral drugs act by inhibiting this catalytic function. Resistance and safety concerns center on the possibility of viral mutations and drug toxicity, respectively. If you need information about the replicase of a specific virus (e.g., SARS-CoV-2, hepatitis C virus), it would be best to specify the virus, since each has a unique replicase complex with specific protein components.

Other names

Viral RNA polymeraseRNA-dependent RNA polymerase (RdRp)Replicase–transcriptase complex (RTC)Qβ replicasePolymerase complex

Nucleoside/nucleotide analogue incorporation leads to chain termination or lethal mutagenesis during viral RNA synthesis; Inhibition of active site catalysis; Possible allosteric inhibition of complex assembly or processivity