Similar to Shiga toxin (Stx), CT and LTs consist of an A-subunit (28 kDa), and five B-subunits (11 kDa each) assembled in a pentamer (AB5 structure). The A-subunit is proteolytically activated by a V.

The first step of toxin activity is the recognition of a specific receptor on the target cell surface. When bound to the receptor, toxins can act at the cell membrane by interfering with signal ...