α-Helix projections of HCV NS5B, wt and mutant PV 3A, and BVDV NS5B sequences. The following amino acid sequences were used drawing the helical wheels: HCV NS5B (aa 571 to 588), PV 3A (aa 61 to 78), the PV 3A TT/KK mutant (aa 61 to 78), and BVDV NS5B (aa 699 to 716). The circles are colored according to the hydrophobic character of the residues (39).