Controlling the Fold
Joel Schneider, University of Delaware
Over the last twenty years, the field of peptide and protein design has been successful in helping to elucidate the factors that govern protein folding and stability. For example, it is now possible to design sequences that fold into desired secondary and tertiary structures such as helices, hairpins, sheets and even entire globular proteins. Although establishing the rules by which protein sequence translates into structure is still a very active area of research, the field is poised to address the question of function. That is, how does one design a sequence that, in addition to folding properly, will perform a useful targeted function? This talk will focus on using folded peptides as building blocks for constructing functional biological materials. We have designed peptides that self-assemble into useful materials, but only do so when correctly folded. When dissolved in water, these peptides exist in an ensemble of unfolded conformations and are thus highly soluble. However, when presented with an appropriate environmental cue, peptides fold into a conformation that rapidly self-assembles affording supramolecular networks that constitute the formation of mechanically rigid hydrogel materials. This mechanism, which links intramolecular folding to self-assembly, allows material formation to be triggered on cue. Peptide-based hydrogels can be designed to function in many capacities. For example, gels have been fabricated as antibacterial agents and delivery vehicles for encapsulated therapeutics such as small molecules, biomolecules, and cells.