- Open Access
Computer simulation of short-range repulsion between supported phospholipid membranes
Biointerphases volume 1, pages40–49 (2006)
The grand canonical Monte Carlo technique is used to calculate the water-mediated pressure between two supported 1,2-dilauroyl-dl-phosphatidylethanolamine (DLPE) membranes in the short separation range. The intra- and intermolecular interactions in the system are described with a combination of a united-atom AMBER-based force field for DLPE and a TIP4P model for water. The total pressure is analyzed in terms of its hydration component and the component due to the direct interaction between the membranes. The latter is, in addition, partitioned into the electrostatic, dispersion, and steric repulsion contributions to give an idea of their relative significance in the water-mediated intermembrane interaction. It is found that the force field used exaggerates the water affinity of the membranes, resulting in an overestimated hydration level and intermembrane pressure. The simulations of the hydrated membranes with damped water-lipid interaction potentials show that both the hydration and pressure are extremely sensitive to the strength of the water-lipid interactions. Moreover, the damping of the mixed interactions by only 10%–20% changes significantly the relative contribution of the individual pressure components to the intermembrane repulsion.
R. Lipowsky and E. Sackmann, Structure and Dynamics of Membranes (Elsevier, Amsterdam, 1995), Vol. 1.
J. N. Israelachvili and H. Wennerström, J. Phys. Chem. 96, 520 (1992).
R. Evans and U. M. B. Marconi, J. Chem. Phys. 86, 7138 (1987).
I. Langmuir, J. Chem. Phys. 6, 873 (1938).
B. V. Derjaguin and N. V. Churaev, in Fluid Interfacial Phenomena, edited by C. A. Croxton (Wiley, Chichester, 1986), Chap. 15.
E. S. A. Jordine, J. Colloid Interface Sci. 45, 435 (1973).
J. Israelachvili and H. Wennerström, Nature (London) 379, 219 (1996).
V. A. Parsegian and R. P. Rand, Langmuir 7, 1299 (1991).
A. Pertsin, D. Platonov, and M. Grunze, J. Chem. Phys. 122, 244708 (2005).
M. Elder, P. Hitchcock, and R. Mason, Proc. R. Soc. London, Ser. A 354, 157 (1977).
J. F. Nagle and M. C. Wiener, Biochim. Biophys. Acta 942, 1 (1988).
Initially, we tried to simulate the interaction of gel-phase DLPE membranes at room temperature and A=42 Å. It turned out, however, that the force field used failed to reproduce the gel state of the membranes, resulting in a substantially disordered structure corresponding rather to the liquid-crystalline state.
S.-J. Marrink and H. J. C. Berendsen, J. Phys. Chem. 98, 4155 (1994).
P. Jedlovszky and M. Mezei, J. Chem. Phys. 111, 10770 (1999).
A. M. Smondyrev and M. L. Berkowitz, J. Comput. Chem. 20, 531 (1999).
D. P. Tieleman, URL http://moose.bio.ucalgary.ca/files/pope.itp.
W. L. Jorgensen and J. D. Madura, Mol. Phys. 56, 1381 (1985).
H. Hauser, I. Pascher, R. H. Pearson, and S. Sundell, Biochim. Biophys. Acta 650, 21 (1981).
W. D. Cornell, P. Cieplak, C. I. Bayly, I. R. Gould, K. M. Merz Jr., D. M. Ferguson, D. C. Spellmeyer, T. Fox, J. W. Caldwell, and P. A. Kollman, J. Am. Chem. Soc. 117, 5179 (1995).
T. Darden, D. York, and L. Pedersen, J. Chem. Phys. 98, 10089 (1993).
R. M. Venable, B. R. Brooks, and R. W. Pastor, J. Chem. Phys. 112, 4822 (2000).
W. Shinoda, N. Namiki, and S. Okazaki, J. Chem. Phys. 106, 5731 (1994).
The use of a statistical ensemble with a fixed lateral area of the simulation cell and a fixed number of lipid molecules could, in principle, partially suppress fluctuations in the local areal density of the lipid, which could affect the membrane permeability. For a simulation cell containing 32 symmetrically independent lipid molecules per monolayer, as in our case, the use of a fixed membrane area ensemble should however have little effect on the fluctuations in the local areal density. This follows from the MD results reported by S. E. Feller and R. W. Pastor, [J. Chem. Phys. 111, 1281 (2005]) who compared the probability distributions of single molecule areas in fixed- and variable-area ensembles for a hydrated lipid membrane with 36 independent molecules per monolayer in the simulation cell.
M. R. Stapleton and A. Panagiotopoulos, J. Chem. Phys. 92, 1285 (1990).
M. Mezei, Mol. Phys. 40, 901 (1980).
R. H. Swendsen and J.-S. Wang, Phys. Rev. Lett. 58, 86 (1987).
A. J. Pertsin, J. Hahn, and H.-P. Grossmann, J. Comput. Chem. 15, 1121 (1994).
A. Pertsin and M. Grunze, J. Phys. Chem. B 108, 16533 (2004).
D. J. Adams, Mol. Phys. 28, 1241 (1974).
T. J. McIntosh and S. A. Simon, Biochemistry 25, 4948 (1986).
Throughout the article, the atom numbering is as suggested by Sundaralingam [Ann. N.Y. Acad. Sci. 195, 324 (1972)]. The two carbon atoms in parentheses belong to the glycerol residue.
T. J. McIntosh and S. A. Simon, Langmuir 12, 1622 (1996).
L. J. Lis, M. McAlister, N. Fuller, R. P. Rand, and V. A. Parsegian, Biophys. J. 37, 657 (1982).
We here imply a large separation range, where the oscillations of water density and hydration pressure can be neglected.
M. Schlenkrich, J. Brickmann, A. D. MacKerell, Jr., and M. Karplus, in Biological Membranes: A Molecular Perspective from Computation and Experiment, edited by K. M. Merz, Jr. and B. Roux (Birkhäuser, Boston, 1996).
The GCMC simulations by Jedlovszky and Mezey (see Ref. 14), cited in the beginning of the previous section, were carried out at a lamellar repeat period D much larger than D 0. No attempt to reproduce the experimental value of n w was undertaken.
A. J. Pertsin and A. I. Kitaigorodsky, The Atom-Atom Potential Method (Springer, Berlin, 1987).
S.-W. Chiu, M. Clark, V. Balaji, S. Subramaniam, H. L. Scott, and E. Jakobsson, Biophys. J. 69, 1230 (1995).
W. L. Jorgensen and J. Tirado-Rives, Proc. Natl. Acad. Sci. U.S.A. 102, 6665 (2005).