What is the mechanism of action of the A fragment of diphtheria toxin?
A) binding the 60S subunit
B) cleaving tRNA
C) the chemical modification of EF2
D) All of the above.
E) None of the above.

Question

Quizplus · Accepted Answer

The A fragment of diphtheria toxin chemically modifies the eukaryotic elongation factor 2 (EF2), which is necessary for protein synthesis. Specifically, the A fragment of diphtheria toxin enzymatically adds an ADP-ribose group to EF2, thereby inactivating it and preventing further elongation of the polypeptide chain. This ultimately leads to cell death. Binding the 60S subunit and cleaving tRNA are not mechanisms of action for the A fragment of diphtheria toxin.

What Is the Mechanism of Action of the a Fragment