Colicin K acts by forming voltage-dependent channels in phospholipid bilayer membranes.
The bactericidal action of colicins K, E1, Ia, and other functionally related colicins involves disruption of active transport and leakage of ions from the cell. We show that a single colicin K molecule can form a voltage-dependent, relatively nonselective, ion-permeable channel of a few picosiemens conductance in a planar phospholipid bilayer membrane. In a membrane containing many of these channels, the ratio of the number of conducting to nonconducting channels changes e-fold per 3.7 mV. We suggest that the physiological effects of colicin K and functionally related colicins result from their ability to form ion-permeable channels in the bacterial plasma membrane.
D001693:Biological Transport, Active / Q000187:drug effects; D003087:Colicins / Q000494:pharmacology*; D004553:Electric Conductivity; D007473:Ion Channels / Q000187:drug effects*; D008563:Membrane Lipids; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins; D008567:Membranes, Artificial; D008954:Models, Biological; D010743:Phospholipids; D014475:Uncoupling Agents / Q000494:pharmacology
D003087:Colicins; D007473:Ion Channels; D008563:Membrane Lipids; D008565:Membrane Proteins; D008567:Membranes, Artificial; D010743:Phospholipids; D014475:Uncoupling Agents