ARTIFICIAL TRANSMEMBRANE ION CHANNELS FROM SELF-ASSEMBLING PEPTIDE NANOTUBES

NATURALLY occurring membrane channels and pores are formed from a larg e family of diverse proteins, peptides and organic secondary metabolit es whose vital biological functions include control of ion flow, signa l transduction, molecular transport and production of cellular toxins. But despite the availability of a large amount of biochemical informa tion about these molecules(1), the design and synthesis of artificial systems that can mimic the biological function of natural compounds re mains a formidable task(2-12). Here we present a simple strategy for t he design of artificial membrane ion channels based on a self-assemble d cylindrical beta-sheet peptide architecture(13). Our systems-essenti ally stacks of peptide rings-display good channel-mediated ion-transpo rt activity with rates exceeding 10(7) ions s(-1), rivalling the perfo rmance of many naturally occurring counterparts. Such molecular assemb lies should find use in the design of novel cytotoxic agents, membrane transport vehicles and drug-delivery systems.