ABSTRACT
In other words, when the energy dierence between the states is on the order of thermal energy (kT), the channel will exist in both conformations at equilibrium. At the single-molecule level, this appears as the channel chattering between closed and open conformations. If ∆G is positive, the channel spends most of its time closed. If ∆G is negative, the channel spends most of its time open. A ligand changes the open probability by simply changing this free energy prole (Figure 4.3b). Most ligands decrease ∆G (stabilizing the open state) and therefore increase the probability of the channel being open.
