Molecular Swings as Highly Active Ion Transporters

Abstract Ions are transported across membrane mostly via carrier or channel mechanisms. Herein, a unique class of molecular‐machine‐inspired membrane transporters, termed molecular swings is reported that utilize a previously unexplored swing mechanism for promoting ion transport in a highly efficient manner. In particular, the molecular swing, which carries a 15‐crown‐5 unit as the ion‐binding and transporting unit, exhibits extremely high ion‐transport activities with EC 50 values of 46 n m (a channel:lipid molar ratio of 1:4800 or 0.021 mol % relative to lipid) and 110 n m for K + and Na + ions, respectively. Remarkably, such ion transport activities remain high in a cholesterol‐rich environment, with EC 50 values of 130 (0.045 mol % relative to lipid/cholesterol) and 326 n m for K + and Na + ions, respectively.