Simulations of the Phase Transition of DPPC Bilayer with and without DPH or TMA-DPH using CHARMM36

Abstract

Early CHARMM all-atom force fields showed transition temperatures well above the experimental value of 315K. We simulated 100 ns for DPH and TMA-DPH dyes in DPPC lipid bilayers at atmospheric pressure and temperatures from 300-330K in 5K increments. Shifts were observed between 305K and 315K in area-per-headgroup, bilayer thickness, lipid-tail order parameters, and steady state dye fluorescence anisotropy. Dye effects on these membrane properties were negligible.