Amino acid residues within the P6 peptide influence CyPA binding. (A) Wild-type (wt), proline-deficient (PA), and single substitutions were evaluated for their ability to bind CyPA; (B) the W312A mutation resulted in reduced replication of a full-length J6-JFH genome. HCV RNAs of wt, W312A, and a polymerase-deficient mutant (GND) were electroporated into Huh-7.5 sh-Luc or sh-A161 stable cell lines. Luciferase assays were performed 4, 24, 48, and 72 h after electroporation. Values were normalized to the 4-h reading, and error bars represent standard deviations from two independent experiments.