10.1021/ct200908r.s001
Shirley
W. I. Siu
Shirley
W. I.
Siu
Kristyna Pluhackova
Kristyna
Pluhackova
Rainer A. Böckmann
Rainer A.
Böckmann
Optimization of the OPLS-AA
Force Field for Long Hydrocarbons
American Chemical Society
2012
alkane
Optimization
hydrocarbon diffusion coefficients
MP
lipid bilayer simulations
GMO
force field
parameter
optimized
methylene hydrogen atoms
OPLS
2012-04-10 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Optimization_of_the_OPLS_AA_Force_Field_for_Long_Hydrocarbons/2532367
The all-atom optimized potentials for liquid simulations
(OPLS-AA)
force field is a popular force field for simulating biomolecules.
However, the current OPLS parameters for hydrocarbons developed using
short alkanes cannot reproduce the liquid properties of long alkanes
in molecular dynamics simulations. Therefore, the extension of OPLS-AA
to (phospho)lipid molecules required for the study of biological membranes
was hampered in the past. Here, we optimized the OPLS-AA force field
for both short and long hydrocarbons. Following the framework of the
OPLS-AA parametrization, we refined the torsional parameters for hydrocarbons
by fitting to the gas-phase ab initio energy profiles calculated at
the accurate MP2/aug-cc-pVTZ theory level. Additionally, the depth
of the Lennard-Jones potential for methylene hydrogen atoms was adjusted
to reproduce the densities and the heats of vaporization of alkanes
and alkenes of different lengths. Optimization of partial charges
finally allowed to reproduce the gel-to-liquid-phase transition temperature
for pentadecane and solvation free energies. It is shown that the
optimized parameter set (L-OPLS) yields improved hydrocarbon diffusion
coefficients, viscosities, and gauche–trans ratios. Moreover,
its applicability for lipid bilayer simulations is shown for a GMO
bilayer in its liquid-crystalline phase.