Genetic engineering has led to the development of fusion protein toxins, which are targeted
effector molecules that combine a targeting ligand such as a growth factor with a cytocidal
moiety such as a plant or bacterial toxin. The first genetically constructed family of fusion
proteins used diphtheria toxin as the toxophore for receptor-binding domain substitution.
Diphtheria toxin consists of three domains: an enzymatically active adenosine diphosphate
(ADP) ribosyltransferase domain, a hydrophobic transmembrane domain, and a C-terminal …