Understanding the physical, chemical and mechanical properties of biomaterialsis important for the rational design of biomedical tools such as imaging and drug delivery agents. Of particular interest is a class of new materials termed peptide amphiphiles,made up of hydrocarbon tails and polypeptide headgroups, which can self-assemble into three-dimensional structures under specific solution conditions. Understanding at a molecular level, the mechanisms by which the peptide amphiphiles interact and self-organize at specific pH conditions is important for designing deliveryvehicles for cancer therapy. Towards this goal we applied constant pH molecular dynamics simulations with the pHreplica-exchange sampling protocol to study the stability and conformational dynamicsof a small model system, the tetramer of IAAAEEEE, at various pH conditions.In our preliminary investigation, we observed that below a transition pH, the tetramer remained stable as �-sheet while above the transition pH the tetramer unfolds to random-coil monomers.The results are in agreement with experimental data.Most importantly, we were able to predict the transition pH and offer atomic details regarding how protonation states of Glu control the self-assembly.

Self-assembly and stability of small model systems at various pH conditions

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.