FIG. 8.

Variable amino acid positions among the patient NS5B isolates. The model of NS5B is derived from the crystal structure of the genotype 1b (BK) Δ55 enzyme (4, 5). The thumb, fingers, and palm regions are colored blue, red, and yellow, respectively. The catalytic Asp318 within the active site is shown as a brown ball and stick and is located toward the center of the figure. The NNI nonnucleoside binding sites are indicated with boldface numbers. The locations of the variable amino acids encoded within the genotype 1b patient NS5B isolates are shown in light green. Because the model is based upon the Δ55 crystal structure, variable residues within the last 55 amino acids are not shown.