Fig. 2.

The HR motif is essential for the PRNTase activity of the CHPV L protein. (a) A schematic structure of the CHPV L protein (2092 aa) is shown, with six amino acid sequence blocks (I–VI) conserved in the NNS RNA viral L proteins. The positions of the putative RdRp and cap methyltransferase (MTase) domains are indicated. The local sequence containing the HR motif in the CHPV L protein is compared with that in the VSV L protein (H1227, the covalent RNA-attachment site). (b) Wild-type (WT) and mutant CHPV L proteins with indicated amino acid substitutions (0.7 μg) were analysed by SDS-PAGE (7.5 % gel) followed by staining with Coomassie brilliant blue. The positions of marker proteins are indicated on the left. (c) The WT and mutant CHPV L proteins (0.3 μg) were subjected to RNA-capping reactions with pppAACAG and [α-³²P]GDP as substrates. Lane 1 indicates no L protein.