El Tor hemolysin of Vibrio cholerae O1 forms channels in planar lipid bilayer membranes.
We investigated the channel formation by El Tor hemolysin (molecular mass, 65 kDa) of Vibrio cholerae O1 biotype El Tor in planar lipid bilayers. The El Tor hemolysin channel exhibited asymmetric and hyperbolic membrane current with increasing membrane potential, meaning that the channel is voltage dependent. The zero-current membrane potential measured in KCI solution showed that permeability ratio PK+/PCl- was 0.16, indicating that the channel is 6-fold more anion selective over cation. The hemolysin channel frequently flickered in the presence of divalent cations, suggesting that the channel spontaneously opens and closes. These data imply that the El Tor hemolysin damages target cells by the formation of transmembrane channels and, consequently, is the cause of osmotic cytolysis.
Ikigai
H
H
Department of Microbiology and Immunology, Showa University School of Medicine, Tokyo, Japan.
Ono
T
T
Iwata
M
M
Nakae
T
T
Shimamura
T
T
D001427:Bacterial Toxins / Q000494:pharmacology*; D003603:Cytotoxins / Q000494:pharmacology*; D007473:Ion Channels; D017136:Ion Transport; D008051:Lipid Bilayers; D008564:Membrane Potentials / Q000187:drug effects; D008567:Membranes, Artificial; D018408:Patch-Clamp Techniques; D010539:Permeability; D012492:Salts / Q000378:metabolism; D014734:Vibrio cholerae / Q000737:chemistry / Q000502:physiology*
D001427:Bacterial Toxins; D003603:Cytotoxins; D007473:Ion Channels; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D012492:Salts