Monodisperse rod formation and liquid crystal behavior of computationally designed parallel peptide coiled-coil ‘bundlemers’

Computationally designed peptides 30 amino acids in length can assemble into the homotetrameric, parallel coiled coils in the aqueous solution, which are also called ‘bundlemers’. The peptide sequences have multiple amino acid side-chain modification positions on the bundlmer exterior as well as the n- and c-termini. Different ‘click’ chemistry functional pairs are used to modify the N-termini to provide potential covalent linking points for the formation of multibundlemer chains. Parallel coiled-coil bundlemers offer the unique possibility for monodisperse, rigid, dimer bundlemer chains when linked together in an end-to-end fashion. Transmission electron microscopy reveals the well-dispersed short rod like structures while small-angle x-ray scattering indicates the monodisperse nature of the rod chain length and diameter. Optical birefringence should be observed in concentrated rod solution under the polarized optical microscopy (POM). With additional C-terminal modification, one can also create ultralong polymers of the parallel bundles. Different inter-bundlemer linking strategies will be discussed to produce different monodisperse lengths of rod-like chains as well as liquid crystals.