Reversible ion transportation switch by a ligand-gated synthetic supramolecular ion channel

J Am Chem Soc. 2014 Nov 5;136(44):15584-95. doi: 10.1021/ja5070312. Epub 2014 Oct 27.

Abstract

Inspired by the regulation of cellular activities found in the ion channel proteins, here we developed membrane-embedded synthetic chiral receptors 1 and 2 with different terminal structures, where receptor 1 has hydrophobic triisopropylsilyl (TIPS) groups and receptor 2 has hydrophilic hydroxy groups. The receptors have ligand-binding units that interact with cationic amphiphiles such as 2-phenethylamine (PA). Conductance study revealed that the receptors hardly show ion transportation at the ligand-free state. After ligand binding involving a conformational change, receptor 1 bearing TIPS termini displays a significant current enhancement due to ion transportation. The current substantially diminishes upon addition of β-cyclodextrin (βCD) that scavenges the ligand from the receptor. Importantly, the receptor again turns into the conductive state by the second addition of PA, and the activation/deactivation of the ion transportation can be repeated. In contrast, receptor 2 bearing the hydroxy terminal groups hardly exhibits ion transportation, suggesting the importance of terminal TIPS groups of 1 that likely anchor the receptor in the membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circular Dichroism
  • Ion Channel Gating
  • Ion Channels / chemistry*
  • Ion Transport
  • Ligands
  • Proton Magnetic Resonance Spectroscopy

Substances

  • Ion Channels
  • Ligands