FIG. 1.

Beta-toxin induces channels in planar lipid bilayers. (A) Stepwise increase in current, driven by a constant voltage, after the introduction of beta-toxin. Channel openings are shown as downward deflections. Beta-toxin was added to the cis side of the membrane in a symmetric solution of 100 mM NaCl. (B) The distribution of single-channel conductance states is represented in an amplitude histogram. For these analyses, current increases on the membrane were monitored at the holding potential of −60 mV. Toxin was added to the cis side at a concentration of 129 nM.