The C4L-O4L model.

<p>(<i>A</i>) The C4L-O4L model is composed of five closed (<i>C</i>_x) and five open states (<i>O</i>_x; x = 0…4). Ligand (<i>L</i>) binding is possible in both the closed and the open channel. The closed-open isomerization can proceed at each degree of liganding. The rate constants and their errors were determined previously <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002721#pcbi.1002721-Kusch2" target="_blank">[22]</a>. <i>k</i>_O3C3 was set equal to <i>k</i>_O4C4. Since for these rate constants only a lower border could be estimated, they were set to 3 s⁻¹ herein if not otherwise noted. This results in <i>k</i>_C3O3 = <i>k</i>_C4O4 = 2.0×10² s^.1. (<i>B</i>) Time-dependent probability to stay in a closed state, <i>P</i>_C,x; (x = 0…4) for a ligand jump (green bar) from zero to 7.5 µM and back to zero. <i>P</i>_c denotes the sum of all <i>P</i>_C,x at each time. (<i>C</i>) Time-dependent probability to stay in an open state, <i>P</i>_O,x; (x = 0…4) for a ligand jump (green bar) from zero to 7.5 µM and back to zero. <i>P</i>_o, the sum of all <i>P</i>_O,x at each time, indicates the measured time course of the total open probability. (<i>D</i>) Scheme of the C4L-O4L model with means of rate constants provided by <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002721#pcbi.1002721.s001" target="_blank">Table S1</a>.