Dimer dissociation of the pore-forming toxin aerolysin precedes receptor binding.
The pore-forming toxin aerolysin is secreted by Aeromonas hydrophila as an inactive precursor. Based on chemical cross-linking and gel filtration, we show here that proaerolysin exists as a monomer at low concentrations but is dimeric above 0.1 mg/ml. At intermediate concentrations, monomers and dimers appeared to be in rapid equilibrium. All together our data indicate that, at low concentrations, the toxin is a monomer and that this species is competent for receptor binding. In contrast, a mutant toxin that forms a covalent dimer was unable to bind to target cells.
Fivaz
M
M
Department of Biochemistry, University of Geneva, 30 quai E. Ansermet, 1211 Geneva, Switzerland.
Velluz
M C
MC
van der Goot
F G
FG
D000818:Animals; D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002850:Chromatography, Gel; D006224:Cricetinae; D003432:Cross-Linking Reagents; D019281:Dimerization; D009154:Mutation; D052899:Pore Forming Cytotoxic Proteins; D011956:Receptors, Cell Surface / Q000378:metabolism*
D001427:Bacterial Toxins; D003432:Cross-Linking Reagents; D052899:Pore Forming Cytotoxic Proteins; D011956:Receptors, Cell Surface; C107096:proaerolysin