Elucidating the stability of bolaamphiphilic polypeptide nanosheets using atomistic molecular dynamics.

Atomistic molecular dynamics was employed to characterize the stability of nanosheets formed by bolaamphiphilic polypeptides. Two different nanosheets (based on RFL4FR and EFL4FE peptide sequences) were simulated to quantify the impact of the bolaamphiphilic nature of the peptides on the structure and energetics of the formed nanostructures. Our results corroborate the structural results obtained experimentally, indicating consistent values for the separation between the peptide planes as well as for nanosheet thickness. Energy analysis indicates that in general the stability of the nanosheets is dominated by electrostatic interactions and nanosheet-water environment interactions contribute considerably to stability. In general, the nanosheets were found to be very stable especially the EFL4FE system that presents a greater energy of interaction between the components of the system. PMF calculations indicate that the free energy required to remove a peptide from the nanosheet is greater than 250 kJ mol-1 reaching the highest value of 310 kJ mol-1 for the extraction of the peptide in the EFL4FE nanosheet.