Identification of a PA-Binding Peptide with Inhibitory Activity against Influenza A and B Virus Replication
Figure 1
Virus type-specific conservation of the PA-binding domain and interaction of PA with PB1.
(A) Upper panel: Alignment of the N-terminal 25 aa of FluA and FluB PB1. The dotted box indicates the 310-helix comprising the core PA-binding domain of PB1. FluA-specific (blue) and FluB-specific (red) aa are highlighted. Middle and lower panels: Alignment of the N-terminal 25 aa of all available FluA and FluB sequences available in the NCBI influenza virus database. Figures on the right hand side indicate the number of sequences present in the database. Grey bars highlight aa which reconstitute the 310-helix of FluA PA and possibly of FluB PA. (B) A/SC35M- and B/Yamagata/73-derived PB1 chimeras used in (b). Note that all PB1 proteins were expressed with C-terminal HA-tags. (C) Human 293T cells were transfected with expression plasmids coding for the indicated PB1 proteins and the C-terminally hexahistidine-tagged PA of FluA (FluA-PAHis). Cell lysates were prepared 24 hours post transfection and subjected to immunoprecipitation (IP) using anti-HA (αHA) agarose. Precipitated material was separated by SDS-PAGE and analyzed by Western blot for the presence of either His- or HA-tagged polymerase subunits using appropriate antibodies. Protein expression was controlled by analyzing equal amounts of cell lysate. Molecular weights are shown in kilodaltons.