Fig. 5: Catalytic domain and ADP-ribosylation activity.

a Structure of PE domain III (grey) in its complex (PDB 2ZIT) with eEF2 (red) and NAD⁺ (yellow). Residues involved in the catalytic activity and the diphthamide target (red^*) are shown as sticks, and loops important for activity and substrate recognition are indicated. The arginine-rich eEF2 interaction site in PE is circled, with NAD⁺ included to highlight the position of the catalytic site. b Collimonas (Cfx; blue), c Chromobacterium (Hmx; green), d Janthinobacterium (Jlx; red), and e Shewanella (Spx; yellow) exotoxins were superposed with PE domain III. Domains I and II were omitted for clarity. Lower panels show the electrostatic surface potential of domain III from each toxin, calculated using the APBS tool in PyMOL (scale from −5, red to +5, blue).