不同水合水平下磷脂双分子层中水的取向动力学

Orientational dynamics of water in phospholipid bilayers with different hydration levels.

作者信息

Zhang Zhancheng, Berkowitz Max L

机构信息

Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.

出版信息

J Phys Chem B. 2009 May 28;113(21):7676-80. doi: 10.1021/jp900873d.

DOI:10.1021/jp900873d

PMID:19413360

Abstract

We performed molecular dynamics computer simulations to study the orientational dynamics of water next to bilayers containing dilauroyl phosphatidylcholine (DLPC) phospholipids with different hydration levels: from 2 to 32 water molecules per lipid. It was observed that water orientational relaxation slowed down as the hydration level of lipids was reduced, in agreement with the recent experimental study. We performed different fits for some of the relaxation curves and observed that fit constants depend strongly on the time period over which the correlation function was measured. We also studied hydrogen bonding properties of water and found that hydrogen bonding switch between water molecules is responsible for a substantial orientational relaxation and that this switch can be explained by the molecular jump model (MJM) in the hydration region of lipid bilayers, as it does in bulk water.

摘要

我们进行了分子动力学计算机模拟，以研究在含有不同水化水平（从每个脂质2到32个水分子）的二月桂酰磷脂酰胆碱（DLPC）磷脂的双层膜附近水的取向动力学。观察到随着脂质水化水平的降低，水的取向弛豫减慢，这与最近的实验研究一致。我们对一些弛豫曲线进行了不同的拟合，发现拟合常数强烈依赖于测量相关函数的时间段。我们还研究了水的氢键性质，发现水分子之间的氢键切换是导致大量取向弛豫的原因，并且这种切换可以用脂质双层水化区域中的分子跳跃模型（MJM）来解释，就像在 bulk water（此处可能是想说“ bulk water”，即“体相水”）中一样。