Alignment of conserved residues between MPN372 and other ARTs. Residues necessary for NAD-binding and catalysis are shown in bold face. PTX, B. pertussis pertussis toxin; LTX, E. coli heat-labile enterotoxin; CTX, cholera toxin; EDIN, Staphylococcus aureus epidermal cell differentiation inhibitor; C3bot, Clostridium botulinum C3 toxin; VIP2, Bacillus cereus vegetative insecticidal protein.