| Type: | Family | Name: | Heat-labile enterotoxin, B chain |
| Description: | Escherichia coliheat-labile enterotoxin is a bacterial protein toxin with an AB5 multimer structure, in which the B pentamer has a membrane-binding function and the A chain () is needed for enzymatic activity []. The B subunits are arranged as a donut-shaped pentamer, each subunit participating in ~30 hydrogen bonds and 6 salt bridges with its two neighbours [].The A subunit has a less well-defined secondary structure. It predominantly interacts with the pentamer via the C-terminal A2 fragment, which runs through the charged central pore of the B subunits. A putative catalytic residue in the A1 fragment (Glu112) lies close to a hydrophobic region, which packs two loops together. It is thought that this region might be important for catalysis and membrane translocation []. | Short Name: | Enterotoxin_B |
