Clostridioides difficile toxin glucosyltransferase (GTD)

The Clostridioides difficile toxin glucosyltransferase (GTD) is the primary cytotoxic effector domain of the large clostridial toxins TcdA and TcdB produced by the bacterium Clostridioides difficile (UniProt: P17154, P18177). Located at the N-terminus of these toxins, the GTD is released into the host cell cytosol following receptor-mediated endocytosis and autoproteolytic cleavage (PubMed: 28846093). Once inside, the enzyme catalyzes the transfer of a glucose moiety from UDP-glucose to highly conserved residues of Rho-family GTPases, including Rho, Rac, and Cdc42 (PubMed: 10601302). This covalent modification permanently inactivates the GTPases, leading to the collapse of the actin cytoskeleton, disruption of the intestinal epithelial barrier, and induction of pro-inflammatory signaling and apoptosis (PubMed: 22431615). These processes are central to the pathogenesis of Clostridioides difficile infection (CDI), which manifests as severe diarrhea and pseudomembranous colitis (PubMed: 26839164). While current clinical strategies like the monoclonal antibody bezlotoxumab target the toxin's binding domains to prevent cellular entry, the glucosyltransferase domain itself is an intensive area of research for the development of small-molecule inhibitors (PubMed: 30104361). Such inhibitors aim to directly block the enzymatic activity of the toxin within the host cell, providing a potential therapeutic avenue to mitigate tissue damage and inflammation.

Other names

TcdA glucosyltransferase domainTcdB glucosyltransferase domainRho-glucosylating toxin effectorGlucosyltransferase domain of Toxin AGlucosyltransferase domain of Toxin B

Neutralization of the toxin to prevent cellular entry or direct inhibition of the glucosyltransferase enzymatic site to prevent Rho GTPase modification.