Referenced in: none

Automatically associated channels: Kir2.3

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

Authors: Takahiro Muraoka, Takahiro Endo, Kazuhito V Tabata, Hiroyuki Noji, Satoru Nagatoishi, Kouhei Tsumoto, Rui Li, Kazushi Kinbara

Journal, date & volume: J. Am. Chem. Soc., 2014 Nov 5 , 136, 15584-95

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/25299449

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.