CPE (Clostridium perfringens enterotoxin), HA-70 type C, and similar aerolysin-type beta-barrel pore-forming proteins
This domain is also known as the clenterotox domain (Chlostridium enterotoxin). Clostridium perfringens enterotoxin is the major virulence determinant for C. perfringens type-A food poisoning. After binding to its receptors, which include particular human claudins, the toxin forms pores in the cell membrane. This family also includes HA-70 type C, a component of the haemagglutinin complex of Clostridium botulinum type C toxin. They belong to the aerolysin family of beta-pore-forming proteins (beta-PFPs). PFPs are generally secreted as water-soluble monomers, which upon binding to target lipid membranes, oligomerize and form transmembrane pores harmful to cells. Beta-PFPs form pores by transmembrane beta-barrels. Aerolysin-type beta-PFPs are believed to use an amphipathic beta-hairpin to form the beta-barrel, are found in all kingdoms of life and many are bacterial toxins. In addition to having a role in microbial infection, they have potential as biotechnological sensors and delivery systems. They share a similar monomeric architecture, with a variable membrane-binding domain and a structurally conserved pore-forming region. A significant portion of the monomeric subunit structure is re-organized to form the pore. Oligomers formed by members of the aerolysin family include: hepta- (aerolysin), octa- (Dln1), and nonameric oligomers (lysenin and monalysin).
Jiyao W et al.(2023). "The conserved domain database in 2023.",