Molecular dynamics simulation of a dipalmitoylphosphatidylcholine bilayer with NaCl.
Molecular dynamics simulations are performed on two hydrated dipalmitoylphosphatidylcholine bilayer systems: one with pure water and one with added NaCl. Due to the rugged nature of the membrane/electrolyte interface, ion binding to the membrane surface is characterized by the loss of ion hydration. Using this structural characterization, binding of Na(+) and Cl(-) ions to the membrane is observed, although the binding of Cl(-) is seen to be slightly weaker than that of Na(+). Dehydration is seen to occur to a different extent for each type of ion. In addition, the excess binding of Na(+) gives rise to a net positive surface charge density just outside the bilayer. The positive density produces a positive electrostatic potential in this region, whereas the system without salt shows an electrostatic potential of zero.
Pandit
Sagar A
SA
Department of Chemistry, Program in Molecular/Cell Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, USA. maxb@unc.edu
Bostick
David
D
Berkowitz
Max L
ML
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry*; D046911:Macromolecular Substances; D008560:Membrane Fluidity; D008564:Membrane Potentials; D008956:Models, Chemical; D012965:Sodium Chloride / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry*
D008051:Lipid Bilayers; D046911:Macromolecular Substances; D012996:Solutions; D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine; D012965:Sodium Chloride