Diphtheria Toxin A antibody – clone 7811

Mouse anti Diphtheria Toxin A antibody is specific for diphtheria toxin A subunit (free and bound). The Diphtheria Toxin A antibody is suitable for use in ELISA assays with mouse anti diphtheria toxin antibody (MAB12177).

Diphtheria toxin (DT) is a potent exotoxin that is a member of the family of ADP-ribosylating bacterial toxins. It was first identified in 1888 as the causative agent of an infectious disease in humans known as diphtheria. DT is secreted by strains of the gram-positive bacterium Corynebacterium diphtheria carrying a lysogenic bacteriophage, which contains the toxin gene (Freeman, VJ).

The toxin is secreted as a precursor molecule and cleaved to produce a single polypeptide chain of 535 amino acids (Mwt 58.342) containing two major functional domains, known as domains A and B. The amino terminal A domain (1-193 amino acids) carries the catalytic domain for ADP-ribosylation of elongation factor 2 (EF2). The carboxyl terminal B domain (194-535 amino acids) is further divided into receptor (R) binding and transmembrane (T) domains (Choe, S). The B domain promotes binding of DT to cells, the internalization of DT by receptor-mediated endocytosis and the entry of the A polypeptide chain into the cytosolic compartment (Greenfield, L).

In humans, DT binds to heparin-binding epidermal growth factor receptor (HB-EGFR) on the surface of cells, and the toxin–receptor complex undergoes receptor-mediated endocytosis. The arginine-rich segment connecting the A and B domains is then cleaved to yield active DT-A and DT-B fragments. The A fragment is translocated across the endocytic membrane into the cytoplasm, a process that is facilitated by DT-B. In the cytoplasm, the catalytic domain A inactivates elongation factor-2, which is an essential component of the protein translation machinery, halting protein synthesis and causing cell death (Collier, RJ).

References

Freeman, V.J. et al (1952). Further observations on the change to virulence of bacteriophage-infected a virulent strains of Corynebacterium diphtheria. J Bacteriol. Mar;63(3):407-14.

Choe, S. et al. (1992). The crystal structure of diphtheria toxin. Nature. May 21;357(6375):216-22.

Greenfield, L. et al. (1983). Nucleotide sequence of the structural gene for diphtheria toxin carried by corynebacteriophage beta. Proc Natl Acad Sci U S A. Nov;80(22):6853-7.

Collier, R.J. (1975). Diphtheria toxin: mode of action and structure. Bacteriol Rev. Mar;39(1):54-85.