Vacuolating cytotoxin precursor, VacA of 1287 aas that forms a hexameric pore in the membranes of target cells after processing (Pyburn et al. 2016). The 88 kDa secreted VacA protein, composed of an N-terminal p33 domain and a C-terminal p55 domain, assembles first into water-soluble oligomers before inserting into membranes. Details for the insertion process are known (Pyburn et al. 2016). The biology of VacAs has been reviewed (Foegeding et al. 2016). VacA preferentially associates with lipid rafts, and the affinity of VacA for rafts is independent of its capacity to oligomerize or form membrane channels (Raghunathan et al. 2018).
VacA of Helicobacter pylori