title: Reversible ion transportation switch by a ligand-gated synthetic supramolecular ion channel.
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.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Muraoka
authors.forename: Takahiro
authors.initials: T
authors.lastname: Endo
authors.forename: Kazuhito V
authors.initials: KV
authors.lastname: Tabata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Noji
authors.forename: Satoru
authors.initials: S
authors.lastname: Nagatoishi
authors.forename: Kouhei
authors.initials: K
authors.lastname: Tsumoto
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Kazushi
authors.initials: K
authors.lastname: Kinbara
mesh_terms: D002942:Circular Dichroism; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry*; D017136:Ion Transport; D008024:Ligands; D066244:Proton Magnetic Resonance Spectroscopy
chemical_list: D007473:Ion Channels; D008024:Ligands