Membrane damage by channel-forming proteins: staphylococcal alpha-toxin, streptolysin-O and the C5b-9 complement complex.
One mechanism through which cells can be damaged involves insertion of alien proteins into the membrane bilayer and the formation of hydrophilic transmembrane pores. Three examples for this process are discussed, namely membrane damage by staphylococcal alpha-toxin, streptolysin-O, and by the terminal C5b-9 complement complex. Common to all is the principle of a transition of the proteins from a water-soluble state to an amphiphilic state, occurring through the appearance or exposure of apolar surfaces during oligomerization of the protein molecules into supramolecular aggregates. The resulting complexes or protein oligomers insert spontaneously into the target lipid bilayer and assume properties akin to those of integral membrane proteins. The protein channels can be isolated from membranes after their solubilization by mild detergents and characterized on a bio-immunochemical and ultrastructural level.
D000818:Animals; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000633:toxicity*; D002462:Cell Membrane / Q000187:drug effects; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000633:toxicity*; D004912:Erythrocytes / Q000187:drug effects; D006460:Hemolysin Proteins; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D007473:Ion Channels / Q000187:drug effects; D008051:Lipid Bilayers / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis*; D008970:Molecular Weight; D009498:Neurotoxins / Q000633:toxicity*; D011817:Rabbits; D013210:Staphylococcus; D013301:Streptolysins / Q000633:toxicity*
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015938:Complement Membrane Attack Complex; D006460:Hemolysin Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; D008565:Membrane Proteins; D009498:Neurotoxins; D013301:Streptolysins; C021091:staphylococcal alpha-toxin; C025964:streptolysin O; D003165:Complement System Proteins