FIG 8.

Sequence of the N terminus of P and summary of effects of point mutations on RdRp activity and P-N⁰ interactions. (A) The sequence of the first 40 N-terminal residues of P is indicated at the top. Residues of the predicted mir motif are boxed. The location of the predicted α-helix is indicated by a blue rectangle below the sequence. The left-hand column indicates the point mutations. Right-hand columns summarize the impact of mutations on (i) the polymerase activity, (ii) in vitro copurification of GST-P[1-40] mutants with N^mono, and (iii) affinity of N^mono for GST-P[1-40] mutants; nd, not determined. Residues identified as critical for both polymerase and interaction with N^mono based on pulldown and SPR data are in red in the sequence. (B) Helical wheel representation (HeliQuest online program) of the putative α-helix located between residues 11 and 28 of P. Residues critical for N⁰-binding are indicated by a star, and the putative site of interaction with the N^mono is indicated by a black half-circle under the wheel. Positively charged residues are in blue, negatively charged residues in red, and hydrophobic residues in yellow.