Training and Validation of a Liquid-Crystalline Phospholipid Bilayer Force Field

We present a united-atom model (gb-fb15)
for the molecular dynamics
simulation of hydrated liquid-crystalline dipalmitoylphosphatidylcholine
(DPPC) phospholipid bilayers. This model was constructed through the
parameter-space minimization of a regularized least-squares objective
function via the ForceBalance method. The objective function was computed
using a training set of experimental bilayer area per lipid and deuterium
order parameter. This model was validated by comparison to experimental
volume per lipid, X-ray scattering form factor, thermal area expansivity,
area compressibility modulus, and lipid lateral diffusion coefficient.
These comparisons demonstrate that gb-fb15 is robust to temperature
variation and an improvement over the original model for both the
training and validation properties.