Fig 10. The configurations of two K⁺ ions in the process of inward permeation.

(a) The ions in a local unperturbed free-energy minimum along the pathway (I) in Fig 8C. (b) The block state in an unstable unperturbed free-energy minimum denoted by Y in Fig 8C. (c) The two ions in another local unperturbed free-energy minimum denoted by X in Fig 8C. (d) The two ions about to enter the cavity. The dehydration of two K⁺ ions is illustrated by the reduction of shared water molecules between them from two (×2) to one (×2), where 2 is the symmetric factor. Note that only two of the four subunits of the channel are shown.