Polymerases of hepatitis C viruses and flaviviruses: Structural and mechanistic insights and drug development.

Highlights: [•] We review available structural data on RNA synthesis by flavivirus polymerases. [•] Initiation is the key regulatory step for both flavivirus NS5 and HCV NS5B. [•] How the extra NS5 methyltransferase activity intervenes remains mysterious. [•] NS5 and NS5B activities are prime targets for antiviral drugs. [•] Advanced NS5B inhibitors are put in the context of the enzyme’s structure. [ABSTRACT FROM AUTHOR]