Orientational dynamics of water in phospholipid bilayers with different hydration levels.
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.
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Zhancheng
Z
Zhang
Max L
ML
Berkowitz
D003198:Computer Simulation; D006860:Hydrogen Bonding; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D010713:Phosphatidylcholines / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D014867:Water; C015153:1,2-dilauroylphosphatidylcholine