Synthesis and Analysis of artificial ion channels toward ionic devices

点击翻译按钮获取中文摘要

Six artificial ion channels 1-6 were synthesized and its characteristic ion channel properties were examined by planner bilayer membrane method.Transmembrane ion channels, bis (7, 12-dimethyl-24-carboxy-3-cholanyl)-N,N'-xylylene dicarbamate 1 and bis [7,12-dimethyl-24-(N,N,N-trimethylethanaminium-2-carboxylate)-3-cholanyl]-N,N'-xylylene dicarbamate dichloride 2 were prepared by linking two amphiphilic cholic acid methyl ethers through biscarbamate bonds. Permeability ratios of potassium cation to chloride anion were 17 and 7.9 for 1 and 2, respectively. Both channels 1 and 2 showed significant potassium selectivity over sodium by a factor of 3.1 and 3.2, respectively.Voltage-dependent artificial ion channels 3 and 4 were produced by introduction of different charged hydrophilic groups into transmembrane bischolic acid ion channel. Thus, compound 3 has carboxylic acid and phosphoric acid groups, and 4 has hydroxyl and carboxylic acid groups. The current-voltage plots of both ion charnnels show clear rectification properties.Two voltage-dependent ion channels composed of dodeca-and pentadecaoligopeptides, NH3+-L-Ala-D-Leu-L-Ala-D-Val-L-Val-D-Val-L-Trp-D-Leu-L-Trp-D-Leu-L-Trp-D-Leu-CO2- (5) and NH3+-L-Val-Gly-L-Ala-D-Leu-L-Ala-D-Val-L-Val-D-Val-L-Trp-D-Leu-L-Trp-D-Leu-L-Trp-D-Leu-L-Trp-CO2- (6), were synthesized. Both oligopeptides have charged species asymmetrically located at the N-and C-terminals. The open probability of these single ion channels was dependent on the applied voltage.