Fabrication strategies of peptide rigid rods with computationally designed coiled-coils

Peptide rigid rods were constructed via thiol-Michael or copper-catalyzed alkyne-azide cycloaddition (CuAAc) 'click' conjugation reactions with tetrameric coiled-coils. These polymer chains are a new class of bio-inspired materials with well-defined nanostructures that display extremely high molecular rigidity and readily form liquid crystals in solution as well as shear-thinning behavior. The building blocks for the rigid rod polymer chains are homotetrameric peptide coiled coil nanoparticles, also called 'bundlemers'. The peptides that constitute the bundlemer particles are computationally designed so that the specific amino acid sequences can be controlled and include non-natural amino acids. Since the sequences are designed and are not taken from any natural protein sequences, one can arbitrarily design building block attributes. Of particular focus is our ability to create bundlemer building blocks with designed net charge. The presentation will discuss results from bundlemer building blocks with a wide range of charge characteristics that all have the same size, shape (i.e., nanocylinders that are 2 by 4 nanometers), and functionality to be linked together to form rigid rod polymers. The solution behavior of the coiled coil building blocks with net charge ranging from highly negatively charged through highly postitively charged will be discussed as well as the behavior of rigid rod polymer chains made from conjugating the building blocks together through click chemistry.