Artificial transmembrane ion channels from self-assembling peptide nanotubes

Abstract

NATURALLY occurring membrane channels and pores are formed from a large family of diverse proteins, peptides and organic secon-dary metabolites whose vital biological functions include control of ion flow, signal transduction, molecular transport and produc-tion of cellular toxins. But despite the availability of a large amount of biochemical information about these molecules¹, the design and synthesis of artificial systems that can mimic the bio-logical function of natural compounds remains a formidable task^2–12. Here we present a simple strategy for the design of artifi-cial membrane ion channels based on a self-assembled cylindrical β-sheet peptide architecture¹³. Our systems—essentially stacks of peptide rings—display good channel-mediated ion-transport activ-ity with rates exceeding 10⁷ ions s⁻¹, rivalling the performance of many naturally occurring counterparts. Such molecular assemblies should find use in the design of novel cytotoxic agents, membrane transport vehicles and drug-delivery systems.