Exotoxin A of Pseudomonas aeruginosa (ETA (also commonly referred to as PE for "Pseudomonas exotoxin"))

Exotoxin A is the most toxic virulence factor produced by _Pseudomonas aeruginosa_. It is a single-chain polypeptide enzyme secreted extracellularly that catalyzes the transfer of an ADP-ribose moiety from NAD+ onto diphthamide residues on eukaryotic elongation factor 2 (eEF2), thereby irreversibly inhibiting protein synthesis within host cells. Structurally, it consists of three domains responsible respectively for receptor binding, membrane translocation, and catalytic activity. The resulting blockade leads rapidly to cell death and contributes significantly to tissue damage during _P. aeruginosa_ infections such as pneumonia or sepsis. Due to its potent mechanism—and structural similarity with diphtheria toxin—it has also been adapted into engineered immunoconjugates aimed at selectively killing tumor cells.

Other names

Exotoxin AETAPseudomonas exotoxinPENAD(+)--diphthamide ADP-ribosyltransferase (EC 2.4.2.36)

For drugs using Exotoxin A or its derivatives: — Targeted delivery to specific cells via antibody or ligand binding, followed by internalization and release of the enzymatic domain into the cytoplasm where it catalyzes ADP-ribosylation of eEF2, leading to inhibition of protein synthesis and cell death