2013 年 71 巻 10 号 p. 1045-1050
Multiblock amphiphiles adopting a multipass transmembrane (MTM) structure on a bilayer membrane have been developed by mimicking the molecular structures of MTM proteins. The amphiphiles are composed of alternative hydrophobic and hydrophilic parts. The hydrophobic parts that penetrate the membrane consist of a fluorescent aromatic group, so that absorption and fluorescent spectroscopy allows the characterization of the assembling/disassembling states of the hydrophobic parts. The spectroscopic analyses revealed that the tetra block amphiphile, bearing four hydrophobic parts, forms intramolecular stacking of the aromatic portions within the membrane, indicating the formation of an MTM structure. Moreover, the tetra block amphiphile shows ion transportation through the membrane following Eisenman sequence XI, where the four molecules self-assemble into a dynamic ion channel with a milli second scale opening-closing motion. The hierarchical construction of a higher-order structure by self-assembly of foldamers can be a rational design of programmable functional molecular organisms.