FIGURE 1.

NS5B RNA-dependent RNA polymerase in the apo form (top, 1C2P.pdb) and in the initiation complex (bottom, 4WTI.pdb). NS5B is shown in the top view (looking down into the RNA binding cleft). The architectural subdomains of the classic open right hand conformation are colored, respectively, blue, red, and green for the fingers, the palm, and the thumb. The fingers extensions and C-terminal tail are colored in cyan and gray, respectively. The β-loop is colored in yellow. Filibuvir, a NNI2 was placed at the NNI2 binding site through alignment with Filibuvir bound structure 3FRZ.pdb and represented as magenta sticks. In the initiation complex (bottom), the dinucleotide-primed RNA template is shown as spheres.