Solution Behavior of Single-Chain Amphiphilic Random Heteropolymers

Amphiphilic synthetic random heteropolymers can provide a bio-inspired means for augmenting and even mimicking bio-macromolecular function. The statistical distribution of chains makes analysis of particular molecules and motifs challenging experimentally. Through molecular dynamics simulations, we can provide nanoscale analysis of individual sequences to provide insight into how these synthetic polymers respond to their environments. Having previously shown multiple dynamic modes and heterogeneous surfaces for the chains in aqueous solution, we now characterize their statistically derived properties when electrostatic and polar interactions are changed through an introduction of organic solvents and small molecules. Environmentally-dependent driving forces to compact globular assembly or chain extension with significant activation barriers are observed when altering solvent. Additionally, we demonstrate that mixing solvents and small molecules alter not only the driving forces to assembly, but also introduce high energy interfaces that can stimulate changes in polymer conformation. Our characterization, leveraging analysis techniques from both polymer physics and protein sciences, enables predictable modification and processing of synthetic polymer assemblies. As native proteins and nucleic acids are, themselves, heteropolymers, our system also provides a synthetic perspective that relays behavioral relationships back to the biomolecules that inspire it.<br/>This work was supported by the Defense Threat Reduction Agency contract HDTRA11910011.