Family of B subunits from the type II heat-labile enterotoxin. The B subunits form a pentameric ring, which interacts with one A subunit. Thus, the structural arrangement of type I and type II heat-labile enterotoxins are very similar [1].

1: Crystal structure of a new heat-labile enterotoxin, LT-IIb. van den Akker F, Sarfaty S, Twiddy EM, Connell TD, Holmes RK, Hol WG; Structure 1996;4:665-678. PMID:8805549