The fit of the drift-diffusion model to the translocation kinetics of WT LF_N and His₆-LF_N over a range of voltages. Drift-diffusion model, blue curves; WT LF_N and His₆-LF_N, red curves. The ordinates are normalized to the conductance before the addition of WT LF_N or His₆-LF_N, and the abscissas are normalized time (t/t_1/2). All of the experiments were performed on the same membrane. The experimental procedure was the same as that described in Fig. 2, except after translocation was completed, WT LF_N or His₆-LF_N was again added to the cis-solution, and the protocol was repeated. At each voltage, the experiment with WT LF_N was followed by that with His₆-LF_N. In contrast to the experiment depicted in Fig. 8, where the addition of His₆-LF_N caused a conductance drop of 18%, the addition of WT LF_N or His₆-LF_N here caused a drop of ∼95%; thus, most of the channels bound two or three LF_Ns.