Free energy of micellization of dodecyl phosphocholine (DPC) from molecular simulation: Hybrid PEACH-BAR method,Journal of Computational Chemistry

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Free energy of micellization of dodecyl phosphocholine (DPC) from molecular simulation: Hybrid PEACH-BAR method
Journal of Computational Chemistry ( IF 3.4 ) Pub Date : 2021-09-24 , DOI: 10.1002/jcc.26751
Xiaokun Zhang ₁ , James T Kindt ₁

Affiliation

A new method to extract the free energy of aggregation versus aggregate size from molecular simulation data is proposed and applied to a united atom model of the zwitterionic surfactant dodecyl phosphocholine in water. This system's slow dissociation rate and low critical micelle concentration (CMC of approximately 1–2 mM) make extraction of cluster free energies directly from simulation results using the “partition-enabled analysis of cluster histogram” (PEACH) method impractical. The new approach applies PEACH to a model with weakened attractions between aggregants, which allows sampling of a continuous range of cluster sizes, then recovers the free energy of aggregation under the original fully-attractive force field using the BAR free energy difference method. PEACH-BAR results are compared with free energy differences calculated via umbrella sampling, and are used to make predictions of CMC, average cluster size, and SAXS scattering profiles that are in fair agreement with experiment.

中文翻译：

来自分子模拟的十二烷基磷酸胆碱 (DPC) 胶束化的自由能：混合 PEACH-BAR 方法

提出了一种从分子模拟数据中提取聚集自由能与聚集体尺寸的新方法，并将其应用于两性离子表面活性剂十二烷基磷酸胆碱在水中的联合原子模型。该系统的缓慢解离速率和低临界胶束浓度（CMC 约为 1-2 mM）使得使用“簇直方图的分区启用分析”（PEACH）方法直接从模拟结果中提取簇自由能是不切实际的。新方法将 PEACH 应用于聚集体之间吸引力减弱的模型，该模型允许对连续范围的簇大小进行采样，然后使用 BAR 自由能差法恢复原始完全吸引力场下的聚集自由能。

更新日期：2021-10-20

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