Engineering dynamic behavior in protein networks

Abstract

In protein-based materials, the amino acid sequence can encode chem. and biol. activity and macroscopic material properties. Here, we describe two approaches to engineer the dynamic behavior of protein networks that contain coiled-coil phys. cross-links. The first is a protein engineering approach in which we have introduced single point mutations within the coiled-coil domain. Hydrogels prepd. from these protein variants exhibit stress relaxation times that vary from less than 1 s to greater than 1000 s. The second approach to modulate network dynamics uses small hydrophobic ligands that bind within the pore of the coiled coil. Addn. of ligands including fatty acids and vitamin D stabilizes phys. cross- links and slows network relaxation by up to three orders of magnitude. Together, these approaches demonstrate that the dynamic behavior of protein networks is highly sensitive to the mol. details of the phys. cross-links. As a result, network dynamics can be encoded within an amino acid sequence or engineered post- fabrication by formulating protein hydrogels with the appropriate ligands.