Figure 17.
A: Schematic representation for anthrax toxin receptor-mediated cell assembly and entry into a target cell50. First, proteolytically activated PA monomers (PA63) oligomerize into the ring-shaped heptameric, (PA63)7, or octameric, (PA63)8, complexes, which are able to dock 3 or 4 enzymatic A components, LF and/or EF, respectively. These oligomeric prepores are then endocytosed and, under the acidic endosomal pH, converted to the transmembrane channels, which transport LF and EF into the cytosol. B: A possible protein unfolding and translocation pathway for anthrax toxin depicted in three successive steps: docking, protein unfolding, and translocation of the unfolded chain. Adapted with permission from ref.50 Copyright 2011. Wiley.