Fig. 1.
Alignment of partial amino acid sequences of the helicase-like domains of some RNA viral replicases. The consensus residues within each signature motif of SF1 helicases are shown in bold. Residues mutated in this study on BaMV protein are indicated by asterisk. Protein secondary structure was predicted at the PSIPRED Protein Structure Prediction Server (http://bioinf.cs.ucl.ac.uk/psipred/). The rectangle and arrow symbolize the α-helix and β-strand, respectively. BaMV, PVX, TMV, TYMV, and HEV represent bamboo mosaic virus, potato virus X, tobacco mosaic virus, turnip yellow mosaic virus and hepatitis E virus, respectively.