Optimization of the OPLS-AA Force Field for Long Hydrocarbons
Optimization of the OPLS-AA Force Field for Long Hydrocarbons
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DOI：
10.1021/ct200908r
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发表时间：
2012-04-01
影响因子：
5.5
通讯作者：
Boeckmann, Rainer A.
中科院分区：
文献类型：
--
作者：
Siu, Shirley W. I.;Pluhackova, Kristyna;Boeckmann, Rainer A.
液体模拟全原子优化势场（OPLS-AA）是模拟生物分子的一种常用力场。然而，目前的OPLS参数的烃开发使用短链烷烃不能重现长链烷烃的液体性质的分子动力学模拟。因此，OPLS-AA的扩展到（磷酸）脂质分子所需的生物膜的研究在过去受到阻碍。在这里，我们优化了短烃和长烃的OPLS-AA力场。在OPLS-AA参数化的框架下，我们通过拟合在精确的MP2/aug-cc-pVTZ理论水平上计算的气相从头算能量分布来改进烃类的扭转参数。此外，还调整了亚甲基氢原子的Lennard-Jones势的深度，以重现不同长度的烷烃和烯烃的密度和蒸发热。部分电荷的优化，最终允许再现凝胶到液相转变温度为十五烷和溶剂化自由能。结果表明，优化的参数集（L-OPLS）产生改善的烃类扩散系数，粘度，和gauche反式比。此外，其适用性的脂双层模拟显示为在其液晶相的转基因生物双层。
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.