The present study concerns the mode of action of a rigidrod-shaped polyol
1 and the correspondinghexamer
2. Proton flux mediated by
1 isshown to be strongly favored over metal cations and a
nions. Themodestselectivity for monovalent cations (Rb
+ >Cs
+ > K
+ > Na
+ ![](/images/entities/ap.gif)
Li
+, Eisenman sequence II) is determined bythedehydration energy and is weakly influenced by the local electric(ionophoric) field. The induction of membranedefects was ruled out by the absence of dye leakage. Structuralstudies by circular dichroism and fluorescencespectroscopy imply that
1 aggregates in polar and nonpolarsolvents, but not in lipid bilayers. Furthermore, itisshown that a very small fraction of
1 adopts a monomerictransmembrane tunnel-like structure which accounts foractivity, while the remainder forms inactive self-assemblies. Theabove results suggest that
1 acts as afunctionalu
nimolecular proton wire which mimics the hydrogen-bonded chainmecha
nism found in bioenergetic systems.