FIGURE 5.
Polymerase activity of PB1-AT6YB chimeras harboring additional FluB-specific amino acid substitutions in the PA-binding domain. A, upper panel, alignment of the consensus sequence of the FluB and FluA PA-binding domain (aa 1–25). Type-specific amino acids are highlighted in bold. Lower panel, PB1-AB chimeras harboring additional FluB-specific amino acids (highlighted in gray). The 310-helix in the FluA PA-binding domain is indicated by a dashed box. B, determination of the FluB polymerase activity of the HA-tagged PB1 chimeras depicted in A. The experiments were essentially carried out as described in the legend for Fig. 1C. Error bars indicate S.D.