Computationally designed coiled coil peptide bundle chains with positive charges: Self-assembly and click conjugation

Computational design has been employed to predict peptide primary structure that will intermolecularly assemble into different net positively charged coiled coils nanostructures. Stable, robust, tetrahelical anti-parallel peptide bundles with net charges varying from 0 to +32 are self-assembled from the computationally designed 29-amino-acid peptides. In this research, +4 charged peptides are synthesized via solid phase peptide synthesis (SPPS) and modified with cysteine or maleimide on the N-termini of single peptides. Those two modified peptides are respectively self-assembled into 4 x 2nm cylindrical peptide bundles through non-covalent interactions and conjugated via Thiol-Michael 'click' react to form coiled coil bundle chains with extreme rigidity. The size and morphology of coiled coil bundle chains self-assembled under various temperatures, pH and solvent conditions are investigated by techniques such as Transmission electron microscopy (TEM) and circular dichroism (CD) spectroscopy. The self-assembled peptide bundles can be further used as building blocks to construct new 1-D nanomaterials. The effect of salt and pH on the solution behavior of the positively charged coiled coil chains will be also discussed.