Journal of the American Chemical Society, Vol.140, No.51, 17992-17998, 2018
An Artificial Molecular Shuttle Operates in Lipid Bilayers for Ion Transport
Inspired by natural biomolecular machines, synthetic molecular-level machines have been proven to perform well-defined mechanical tasks and measurable work. To mimic the function of channel proteins, we herein report the development of a synthetic molecular shuttle, rotaxane 3, as a unimolecular vehicle that can be inserted into lipid bilayers to perform passive ion transport through its stochastic shuttling motion. The rotaxane molecular shuttle is composed of an amphiphilic molecular thread with three binding stations, which is interlocked in a macrocycle wheel component that tethers a K+ carrier. The structural characteristics enable the rotaxane to transport ions across the lipid bilayers, similar to a cable car, transporting K+ with an EC50 value of 1.0 mu M (3.0 mol % relative to lipid). We expect that this simple molecular machine will provide new opportunities for developing more effective and selective ion transporters.