Conformational entropy of a bilayer membrane derived from a molecular dynamics simulation

Edholm, Olle; Berendsen, Herman J. C.; Ploeg, P. van der

doi:10.1080/00268978300100281

Cited by 42 publications

(20 citation statements)

References 12 publications

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“…It has been shown previously [I] that the experimental entropy for the K + KM phase transition in lead(I1) decanoate is in good agreement with that predicted from a molecular dynamics simulation of chain disordering [39].…”

Section: Thermodynamics Of the Phase Transitionssupporting

confidence: 78%

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Thermotropic Polymorphism in Liquid-Crystalline Lead(II) Alkanoates

et al. 1988

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Lead(I1) carboxylates with even chain lengths from octanoate to octadecanoate have been investigated by differential scanning calorimetry, polarizing optical microscopy, X-ray diffraction, and dilatometry, together with Raman, infrared, and *07Pb N.M.R. spectroscopy. The reassignment of the high temperature mesophase as smectic A (L,) for the octanoate to dodecanoate is confirmed. This phase is most stable for the decanoate. The intermediate temperature mesophase is a highly ordered three dimensional lamellar structure based on ionic layers. The alkyl chains in this phase are partially disordered (melted) through the introduction of gauche conformations and show decreased lateral interactions; however, they remain largely in an extended conformation due to the constraints imposed by the ionic network. Melting of the alkyl chains occurs therefore in more than one step. Re-cooling to the crystalline phase appears to result in a different polymorphic crystalline form (albeit still lamellar) from the original.

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Section: Thermodynamics Of the Phase Transitionssupporting

confidence: 78%

“…The same criticism does not apply to molecular dynamics calculations [39], where one is modelling the total change in conformation and packing of the chains. However, this can be circumvented by obtaining entropy changes from a free energy decomposition [41].…”

mentioning

confidence: 95%

Thermotropic Polymorphism in Liquid-Crystalline Lead(II) Alkanoates

et al. 1988

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“…The conventional model of a biological membrane is a lipid bilayer in which are embedded many proteins and sterols (Cevc and Marsh, 1987) all held together by noncovalent interactions. Interest in modeling bilayer membranes using molecular dynamics has increased dramatically (Bassolino-Klimas et al, 1993; Biswas and Shurmann, 1991;Charifson et al, 1990;Damodaran et al, 1992;Merz, 1993, 1994;Edholm et al, 1983;Edholm and Johansson, 1987;Edholm and Nyberg, 1992; Egberts and Berendsen, 1988;Essex, 1992;Fukada et al, 1993;Heller et al, 1993; Khalatur and Pavlov, 1987;Marrmnk et al, 1993; van der Ploeg and Berendsen, 1982Stouch et al, 1991Stouch et al, , 1994Stouch, 1993;Venable et al, 1993;Xiang, 1993). Of these only a few have been attempts with phospholipid molecules and explicit solvent (Damodaran et al, 1992;Merz, 1993,1994;Essex, 1992;Heller et al, 1993;Stouch, 1993;and Venable et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Head group and chain behavior in biological membranes: a molecular dynamics computer simulation

Robinson

Richards

Thomas

et al. 1994

Biophysical Journal

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A computer-modeled hydrated bilayer model of the lipid 2,3-dimyristoyl-D-glycero-1-phosphorylcholine in the L alpha phase was built. Particular care was taken in building the starting structure with the inclusion of structural detail reported in experiments on the L alpha phase. Molecular dynamics simulations using the molecular dynamics and energy refinement program AMBER 3.1 force field with an optimized parameters for liquid simulation parameter set were run to study the motions and conformations of the lipid molecules and characterize the behavior and structure of the head groups and the hydrocarbon lipid chains. Although the head groups were observed to show great flexibility, certain head-group torsion combinations appeared favored. The observed tilt of the lipid chains is discussed and is consistent with previous experimental findings. Motion of the lipid chains is shown to be correlated with those chains immediately surrounding, but correlation with chains more distant varies with time.

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“…A considerable amount of experimental data is available on this system, which exhibits two mesophases between the solid and isotropic liquid. Further, the chain length is of interest because a number of good theoretical calculations have been performed on chain disordering in 10 carbon atom systems (24)(25)(26)(27). From X-ray powder diffraction studies, a layered lamellar structure has been confirmed for the solid phase, with planes oflead(II) ions separated by the carboxylate chains (20,28).…”

Section: General Phase Behaviourmentioning

confidence: 95%

The Phase Behaviour of Metal(II) Soaps in One, Two and Three Component Systems

Burrows

1990

The Structure, Dynamics and Equilibrium Properties of Colloidal Systems

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ABSTRACT. A brief review is presented of the thennal behaviour of the long-chain carboxylates (soaps) of divalent metal ions, and some of the important factors influencing the phase behaviour are highlighted. A more detailed discussion is given of the behaviour of the lead(II) soaps, where a variety of physical techniques have been employed to characterize the phase structures. For the straight chain soaps, two liquid crystalline phases are observed between solid and isotropic liquid, whereas for longer chain homologues only one mesophase is observed. The effects of unsaturation and chain branching are discussed, and indications given of the major energetic contributions to the phase transitions. In some cases polymorphism is observed in the solid phases, and metastable phases produced on cooling may be stable for long times. The phase behaviour of divalent metal soaps in two and three component systems is examined, both in terms of the effect of additional components on phase structures, and of the solubility of soaps in a variety of polar and non-polar solvents.

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Conformational entropy of a bilayer membrane derived from a molecular dynamics simulation

Cited by 42 publications

References 12 publications

Thermotropic Polymorphism in Liquid-Crystalline Lead(II) Alkanoates

Thermotropic Polymorphism in Liquid-Crystalline Lead(II) Alkanoates

Head group and chain behavior in biological membranes: a molecular dynamics computer simulation

The Phase Behaviour of Metal(II) Soaps in One, Two and Three Component Systems

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