Final answer:
The structure of ADP ribosylating toxin involves an enzymatic component that transfers ADP-ribose to host proteins, exemplified by diphtheria toxin's inhibition of protein synthesis which can be studied to design ribonuclease inhibitors.
Step-by-step explanation:
The structure of the ADP ribosylating toxin refers to the enzymatic component of certain bacterial toxins that modify host cell proteins by the transfer of ADP-ribose from NAD+ to specific amino acids in the host proteins. One example given is the mechanism of the diphtheria toxin, where the A subunit of the toxin inactivates elongation factor 2 by transferring an ADP-ribose, consequently inhibiting protein synthesis and leading to cell death. These toxins play a significant role in bacterial pathogenesis, and understanding their structure can assist in the development of inhibitors as noted in references discussing ribonuclease inhibitors and the structure of ribonuclease A complexed with various inhibitors.