Lattice solution assembly of coiled coil 'bundlemer' peptides in aqueous solutions

Bundlemers are homotetrameric, antiparallel coiled coils in aqueous solution. The constituent peptide molecules are computationally designed and have great design flexibility with respect to sequence modifications and side chain functionality. During solid phase peptide synthesis, protecting groups are utilized on the functional side chains of amino acids to prevent side reactions. Alloc, or allyloxycarbonyl, is used as a common protecting group on the side chain of lysine in order to protect the primary amine. In this work, alloc groups are kept in the final, assembling peptides to be used as crosslinking points due to the carbon-carbon double bond on the alloc. The placement of these alloc groups on the periphery of bundlemer particles results in unique lattice-like structure self-assembly in solution. The effect of peptide net charge and solution pH on the assembly will be described. Transmission electron microscopy (TEM) and small angle x-ray scattering (SAXS) was used to characterize this assembly behavior.