Cytolytic toxins and surface activity

Surface-active properties of alpha-toxin and delta-lysin, two cytolytic protein exotoxins of the bacterium Staphylococcus aureus are summarised. The relevance of differences in surface charge density on membranes is discussed in relation to possible mechanisms of binding and membrane penetration by alpha-toxin. An hypothesis for the mechanism of membrane disruption by delta-lysin involving the formation of hydrophilic transmembrane pores is proposed.