Self-Assembling Coiled-Coil Peptide Nanotubes with Biomolecular Cargo Encapsulation.

We report a coiled-coil trimeric peptide based on the known GCN4 zipper motif that self-assembles into nanotubes with diameters on the order of a few hundred nanometers to a micron. The dimensional morphology of these tubular structures was observed to be tunable by altering the properties of the buffer during assembly. Structural evidence from X-ray scattering and electron microscopy suggest that tube assembly takes place in structural tiers leading to a hexagonal close-packed arrangement of the coiled-coils. The hollow tubes were observed to selectively encapsulate fluorescein-labeled anionic dextran, as a result of electrostatic interactions between the inner tube surface and negatively charged cargo. The ability of these nanotubes to house biomolecular cargo endows them with potential for molecular storage and drug delivery applications.