Biomembrane Model from Stable Polymer Membrane Having Polypeptide Domains as Channels

Abstract

A novel polymer membrane having a transmembrane permeation pathway (channel) was prepared from a polyvinyl-polypeptide graft copolymer. The transmembrane continuous phases of the hydrophilic polypeptide were found to be formed in the stable matrix from vinyl polymer and to function as a permeation pathway for polar substances; the polypeptide domain is regarded as a membrane protein model. The infrared and circular dichroism spectra of the membrane showed the pH-dependent conformational change of the polypeptide segment. Regulation of permeability and permselectivity was performed by pH based on the conformational transition of the channel-composing polypeptide. In addition, the membrane has been found to respond to divalent cations, cationic surfactants, urea, and organic solvents in terms of membrane permeability as well as conformational status of polypeptide.