Electrostatic Coassembly of Coiled-Coil Peptide Bundlemers with Complementary Charges into Porous 2D Lattices

A series of highly charged coiled-coil peptide particles, or "bundlemers," with only a single charge type in a bundlemer particle (i.e., either all positive charges or all negative charges) were computationally designed with varied charge spatial display and amino acid types. Electrostatic complexation of oppositely charged single-charge-type peptide bundlemers resulted in the formation of well-defined porous lattices. Structural characterization using electron microscopy and small-angle X-ray scattering revealed that the lattice morphology is modulated by the charged side-chain spatial arrangement on the coiled-coil particle surfaces and the relative stoichiometry of surface charges in mixtures of oppositely charged bundlemer particles. Furthermore, alterations in the side-chain length and type of charged side chains on the coiled-coil particle surfaces enabled further control of lattice formation. Lattice assembly through single-charge bundlemer complexation is in stark contrast to the amorphous structures formed using bundlemer coiled-coil particles with mixed-charge character (i.e., containing both negatively and positively charged amino acids in the same particle). These results provide a robust framework for supramolecular nanostructure formation through rational surface charge manipulation of bundlemer building blocks.