Controlling Solution Behavior of a Novel Peptide-based Polymer

Novel polymer materials are synthesized using N-terminal modified peptide coiled-coils via thiol-maleimide ‘click’ reaction. One example is peptide rigid rods, formed by conjugation of anti-parallel, tetrameric coiled-coils (bundlemers). Concentrated solutions of the rod chains display significant birefringence, thus showcasing the presence of lyotropic liquid crystal phases. In this work, we further explore ways to control liquid crystal behavior of rigid rods with new computational designs of peptide sequences. Various degrees of alignment of rigid rods in their liquid crystal phases can be achieved by manipulation of their net charge in solution. To understand the charge interaction of rigid rods, experiments were conducted using different sequences (net charge from -24 to +28 per bundlemer at pH 7) at the same pH as well as the same sequence at different solution pH and ionic strength. We also studied how these different solution conditions can affect semiflexible chains, which were synthesized with bundlemers connected to tetra-functional organic linkers. Inter- and intra-molecular electrostatic interactions of semiflexible chains are expected to change with its net charge, thus affecting its chain conformation in solution. Preliminary TEM and cryoTEM data will be presented.