Tracheal cytotoxin

Tracheal cytotoxin (TCT) is a 921 dalton glycopeptide released by Bordetella pertussis and Neisseria gonorrhoeae.

In 1980, it was discovered that B. pertussis could attach to hamster tracheal epithelial (HTE) cells, and also, that the supernatant from the cultured bacterium could disrupt the cell cycle of uninfected cells. This prompted the scientists W. E. Goldman, D. G. Klapper, and J. B. Baseman to isolate and characterize a novel substance from B. pertussis supernatant. The novel disaccharide tetrapeptide that they had purified showed toxicity for HTE cells and tracheal ring cultures. Subsequently, they named the newly sequestered molecule tracheal cytotoxin (TCT).

TCT is a soluble piece of peptidoglycan (PGN) found in the cell wall of all gram-negative bacteria. Like all PGNs, TCT is composed of a disaccharide and a peptide chain. The IUPAC name for TCT is N-acetylglucosaminyl-1,6-anhydro-N-acetylmuramyl-(L)-alanyl-γ-(D)-glutamyl-mesodiaminopimelyl-(D)-alanine. It is classified as a DAP(Diaminopimelic acid)-type PGN due to the third amino group within the chain being a diaminopimelyl peptide.

The DAP residue is responsible for directly bonding to the D-alanine peptide of another PGN molecule, thus aiding TCT's attachment within the cell wall.

...
Wikipedia