FIG. 1.

Recombinant WNV NS5 and MTase proteins. (A) WNV genome. The 5′ and 3′ termini of the WNV genome contain an m⁷GpppAm cap structure and CU_OH, respectively. The NS5 protein (905 amino acids) consists of the MTase and RdRp domains connected by a bridge domain harboring an NLS. (B) Purification of wild-type MTase and NS5 proteins. Uninduced and IPTG-induced bacteria and purified proteins were analyzed by SDS-PAGE and stained with Coomassie blue. (C) Mutant MTases each containing an alanine substitution within the conserved K₆₁-D₁₄₆-K₁₈₂-E₂₁₈ tetrad. The sizes (kilodaltons) of protein standards (Marker) and recombinant proteins are indicated on the left and right, respectively.