title: Artificial ion channels showing rectified current behavior.
abstract: Voltage-dependent artificial ion channels 3 and 4 were synthesized. Two cholic acid derivatives were connected through a m-xylylene dicarbamate unit at 3-hydroxyl groups. Asymmetries were introduced by terminal hydrophilic groups, carboxylic acid and phosphoric acid for 3 and hydroxyl and carboxylic acid for 4. Under basic conditions, these headgroups in 3 and 4 are expected to be dissociate into -1/-2 (pH 8.2) and 0/-1 (pH 7.2), respectively. Single ion channel properties were examined by a planar bilayer lipid membrane method under symmetrical 500 mM KCl at pH 8.2 or 7.2. When 3 and 4 were introduced into the bilayer membrane under application of positive voltage (a positive-shift method), the current values at positive applied voltage were larger than the corresponding ones at the negative applied voltage. The current-voltage plots were fitted by curves through a zero point to show clear rectification properties. The direction of rectification could be controlled by positive- or negative-shift methods. Vectorial alignment of terminal headgroup charges by the voltage-shift incorporation is essential for giving voltage-dependent rectified ion channels.
authors.affiliation: CREST, Japan Science and Technology Corporation (JST), Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Goto
authors.forename: M
authors.initials: M
authors.lastname: Yamamura
authors.forename: A
authors.initials: A
authors.lastname: Satake
authors.forename: Y
authors.initials: Y
authors.lastname: Kobuke
mesh_terms: D002219:Carbamates / Q000737:chemistry; D002793:Cholic Acids / Q000138:chemical synthesis / Q000737:chemistry; D004553:Electric Conductivity; D015640:Ion Channel Gating; D007473:Ion Channels / Q000138:chemical synthesis / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry; D008564:Membrane Potentials; D008567:Membranes, Artificial; D008968:Molecular Conformation; D011189:Potassium Chloride / Q000737:chemistry; D014992:Xylenes / Q000737:chemistry
chemical_list: D002219:Carbamates; D002793:Cholic Acids; D007473:Ion Channels; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D014992:Xylenes; D011189:Potassium Chloride