(182m) Understanding the Impact of Non-Natural Amino Acid Incorporation on the Assembly of Multifunctional Collagen Mimetic Peptides: Simulations and Experiments

Authors: 
Taylor, P., University of Delaware
Jayaraman, A., University of Delaware
Kloxin, A. M., University of Delaware
Hilderbrand, A., University of Delaware
This poster focuses on our multi-scale simulations and experimental studies on the self-assembly and melting transitions of thermoresponsive peptides, specifically collagen-mimetic peptides (CMPs). CMPs are biomimetic polymers that mimic the extracellular matrix protein, collagen, and are composed of repeat units of (X-Y-G), where X and Y are usually proline (P) and hydroxyproline (O), and G is glycine. Three CMP strands associate to form the CMP triple helix which is stabilized via inter-chain hydrogen bonding involving the amine (N-H) hydrogen of glycine and the carbonyl (C=O) oxygen of proline. In this work, we investigated the effects of charged and non-natural amino acid substitutions of the canonical (POG) triplet on the thermal stability of the CMP triple helix. In experiments, the addition of a non-natural amino acid, i.e. an allyloxycarbonyl-protected lysine residue (K-alloc), in CMP allowed for cross-linking in hydrogel systems. These hydrogels act as a platform for recapitulating the hierarchical self-assembly of native collagen for biomedical applications. Furthermore, using atomistic and coarse-grained molecular dynamics (MD) simulations, we showed that the incorporation of K-alloc residues in CMP destabilized the triple helix, mirroring our experimental melting temperatures. Our atomistic simulations showed that the addition of a single K-alloc residue in CMP impacted the chain conformations of the CMP strands but were unable to capture CMP melting due to the intractable simulation time required to observe melting. Thus, we performed coarse-grained MD simulations using our new CMP CG model and showed that the presence of the K-alloc residue also impacted the chain conformations and stability of the triple helix at experimentally relevant length scales. Overall, our work highlights the predictive capabilities of MD simulations in guiding experiments as these peptides systems are often costly and difficult to synthesize, thus streamlining the discovery of new, biomimetic platforms.