Figure 2

Scheme of anthrax toxin-based delivery with subsequent pulldown to test successful refolding. (a) LFN-DARPin-HA-tag-avi-tag gets delivered to the cytosol and biotinylated by cytosolically present BirA. Protein stuck in the endosome does not get biotinylated. Cells are harvested, extracted with digitonin, and the cytosolic fraction is separated from the residual pellet by centrifugation. (b) The cytosolic fraction is added to streptavidin magnetic beads and the unbound fraction is removed. The pulldown fraction is then analyzed further via western blotting and ELISA.