COMPUTER-SIMULATION OF A PHOSPHOLIPID MONOLAYER-WATER SYSTEM - THE INFLUENCE OF LONG-RANGE FORCES ON WATER-STRUCTURE AND DYNAMICS
COMPUTER-SIMULATION OF A PHOSPHOLIPID MONOLAYER-WATER SYSTEM - THE INFLUENCE OF LONG-RANGE FORCES ON WATER-STRUCTURE AND DYNAMICS
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DOI：
10.1063/1.464358
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发表时间：
1993-06-15
影响因子：
4.4
通讯作者：
STOUCH, TR
中科院分区：
文献类型：
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作者：
ALPER, HE;BASSOLINO, D;STOUCH, TR
分子动力学模拟水以上的脂质（二肉豆蔻酰磷脂酰胆碱）单层的结构和动力学的水是相当敏感的治疗的长程力。为了获得一个定量估计的扰动引入到水的行为截断的潜力，我们计算各种结构和动力学性质的水模拟采用不同的截止。当采用10-14埃量级的电势截止时，单层附近的水的性质表现出高达20%-25%的扰动，其延伸到水中30-35埃。采用约30埃的截止值导致水行为在单层上方基本上均匀。我们还提出了一个定量的描述，在模拟采用不同的截止值的单个原子所经历的力的差异。尽管采用14埃和30埃有效截止值的模拟之间的水性质存在显着差异，但单个原子上的力仅相差约1%。人们还发现，脂质的运动并没有显着影响扰动的水的性质。模拟与较短的截止值，其中脂质原子点电荷被设置为零，显示没有扰动水结构。邻近用于保持系统密度的排斥壁的水在有效的30埃截止时也表现出与14埃截止时不同的行为。
Molecular dynamics simulations of water above a lipid (dimyristoylphosphatidylcholine) monolayer show that the structure and dynamics of the water are quite sensitive to the treatment of the long range forces. To obtain a quantitative estimate of the perturbations introduced into the water behavior by truncation of the potential, we calculate various structural and dynamical properties of the water for simulations employing different cutoffs. When potential cutoffs on the order of 10-14 angstrom are employed, the properties of water near the monolayer exhibit perturbations of up to 20%-25% that extend 30-35 angstrom into the water. Employing cutoffs on the order of 30 angstrom leads to water behavior that is essentially uniform above the monolayer. We also present a quantitative description of the difference in the force experienced by individual atoms in simulations employing different cutoffs. Despite the significant difference in the water properties between simulations employing 14 angstrom and effective 30 angstrom cutoffs, the forces on the individual atoms differ by only approximately 1 %. It was also found that the motion of the lipids did not significantly affect the perturbations in the water properties. Simulations with shorter cutoffs in which the lipid atomic point charges were set to zero-showed no perturbation in water structure. Water adjacent to a repulsive wall employed to maintain the system density also exhibited different behavior with effective 30 angstrom cutoffs than with 14 angstrom cutoffs.