2.B.48. The Synthetic Transmembrane Ion Shuttling/Fishing (TISF) Family
Ye et al. 2019 reported an 'ion-fishing' mechanism as an alternative to conventional carrier or channel mechanisms for mediating efficient and selective transmembrane K+ fluxes. The molecular framework underlying the fishing mechanism consists of a fishing rod, a fishing line and a fishing bait/hook, which encloses the ion to be transported across the membrane. It is simple but modularly modifiable. This feature enables rapid construction of a series of molecular ion fishers with different ion transport patterns. While more efficient ion transport is generally achieved by using 18-crown-6 as the fishing bait/hook, ions are transported selectivity since the K+/Na+ ratio depends on the length of the fishing line, with the most selective MF6-C14 exhibiting high selectivity (K+/Na+ = up to 18) and high activity. Since the 'cage' inclosing the transported ion shuttles across the membrane, we classify this type of transport as a carrier-type rather than a channel-type.