Quantum-chemical and empirical calculations on phospholipids. III. Hydration of the dimethylphosphate anion

Frischleder, H.; Gleichmann, S.; Krahl, R.

doi:10.1016/0009-3084(77)90094-9

Cited by 34 publications

(9 citation statements)

References 16 publications

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“…Therefore, we suggest that the strongly bound water observed in spectroscopic experiments are the water molecules that are H-bonded to DMPC oxygens. This agrees well with theoretical calculations of Frischleder et al…”

Section: Resultssupporting

confidence: 93%

Hydrogen Bonding of Water to Phosphatidylcholine in the Membrane As Studied by a Molecular Dynamics Simulation: Location, Geometry, and Lipid−Lipid Bridging via Hydrogen-Bonded Water

et al. 1997

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Hydrogen (H-) bonding between water and phosphatidylcholine was studied using a molecular dynamics simulation of a hydrated phosphatidylcholine bilayer membrane in the liquid crystalline phase. A membrane in the liquid-crystalline phase composed of 72 l-α-dimyristoylphosphatidylcholine (DMPC) and 1622 water molecules was generated, starting from the crystal structure of DMPC. At the beginning of the equilibration process, the temperature of the system was raised to 550 K for 20 ps, which was effective in breaking the initial crystalline structure. The thermodynamic and structural parameters became stable after the equilibration period of 1100 ps, and the trajectory of the system obtained during the following 500 ps agreed well with most of the published experimental data. Each DMPC molecule forms 5.3 H-bonds with water, while only 4.5 water molecules are H-bonded to DMPC. The primary targets of water for the formation of H-bonds are the non-ester phosphate oxygens (4.0 H-bonds) and the carbonyl oxygens (∼1.0 H-bonds). Of DMPC's H-bonds, 1.7 are formed with water molecules that are simultaneously H-bonded to two different DMPC oxygens (bridging water). In effect, approximately 70% of the DMPC molecules are linked by water molecules and form clusters of two to seven DMPC molecules. Approximately 70% of the intermolecular water bridges are formed between non-ester phosphate oxygens. The rest are formed between non-ester phosphate and carbonyl oxygens. About half of the intermolecular water bridges are involved in formation of multiple bridges, where two DMPC molecules are linked by more than one parallel bridge. These results suggest a possibility that water bridges are involved in reducing head group mobility and in stabilizing the membrane structure. Non-ester phosphate oxygen of DMPC makes one, two, or three H-bonds with water, but two H-bonds are formed most often (≈60%). In the case where two H-bonds are formed on non-ester phosphate or carbonyl oxygens, the average geometry of H-bonding is planar trigonal (in the case of water oxygen with two H-bonds, geometry is steric tetragonal). When oxygen atoms form three H-bonds, the geometry of H-bonding is steric tetragonal both for non-ester phosphate and water oxygens. On average, H-bonds make nearly right angles with each other when two or three water molecules are bound to the same DMPC oxygen, but the distribution of the angle is broad.

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Section: Resultssupporting

confidence: 93%

Hydrogen Bonding of Water to Phosphatidylcholine in the Membrane As Studied by a Molecular Dynamics Simulation: Location, Geometry, and Lipid−Lipid Bridging via Hydrogen-Bonded Water

et al. 1997

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“…This is consistent with current views on the hydration properties of phospholipids (Hauser & Phillips, 1979) and also with the data of Schumacher & Sandermann (1976), who found a much greater hydration of the sodium salt of DL-phosphoserine than of the free acid. Evidence for strong association of water with the phosphate group and relatively little association with the amino group comes from theoretical studies on the hydration of model compounds for polar head-group segments (Port & Pullman, 1973;Frischleder et al, 1977). It was found in these latter two studies that the binding energy for water molecules to dimethyl phosphate is 108.8 (25.9) kJ (kcal)/mol for the first water molecule, decreasing to 43.3 (10.3) kJ (kcal)/mol for the seventh water molecule, whereas the binding energy to tetramethylammonium is only 43.3 (10.3) kJ (kcal)/mol for the first water molecule.…”

Section: Discussionmentioning

confidence: 99%

Titration of the phase transition of phosphatidylserine bilayer membranes. Effects of pH, surface electrostatics, ion binding, and head-group hydration

Cevc¹,

Watts²,

Marsh³

1981

Biochemistry

242

161

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The dependence of the gel-to-fluid phase transition temperature of dimyristoyl- and dipalmitoylphosphatidylserine bilayers on pH, NaCl concentration, and degree of hydration has been studied with differential scanning calorimetry and with spin-labels. On protonation of the carboxyl group (pK2app = 5.5), the transition temperature increases from 36 to 44 degrees C in the fully hydrated state of dimyristoylphosphatidylserine (from 54 to 62 degrees C for dipalmitoylphosphatidylserine), at ionic strength J = 0.1. In addition, at least two less hydrated states, differing progressively by 1 H2O/PS, are observed at low pH with transition temperatures of 48 and 52 degrees C for dimyristoyl- and 65 and 68.5 degrees C for dipalmitoylphosphatidylserine. On deprotonation of the amino group (pK3app = 11.55) the transition temperature decreases to approximately 15 degrees C for dimyristoyl- and 32 degrees C for dipalmitoylphosphatidylserine, and a pretransition is observed at approximately 6 degrees C (dimyristoylphosphatidylserine) and 21.5 degrees C (dipalmitoylphosphatidylserine), at J = 0.1. No titration of the transition is observed for the fully hydrated phosphate group down to pH less than or equal to 0.5, but it affinity for water binding decreases steeply at pH greater than or equal to 2.6. Increasing the NaCl concentration from 0.1 to 2.0 M increases the transition temperature of dimyristoyphosphatidylserine by approximately 8 degrees C at pH 7, by approximately 5 degrees at pH 13, and by approximately 0 degrees C at pH 1. These increases are attributed to the screening of the electrostatic titration-induced shifts in transition temperature. On a further increase of the NaCl concentration to 5.5 M, the transition temperature increases by an additional 9 degree C at pH 7, 13 degree C at pH 13, approximately 7 degree C in the fully hydrated state at pH 1, and approximately 4 and approximately 0 degree C in the two less hydrated states. These shifts are attributed to displacement of water of hydration by ion binding. From the salt dependence it is deduced that the transition temperature shift at the carboxyl titration can be accounted for completely by the surface charge and change in hydration of approximately 1 H2O/lipid, whereas that of the amino group titration arises mostly from other sources, probably hydrogen bonding. The shifts in pK (delta pK2 = 2.85, delta pK3 = 1.56) are consistent with a reduced polarity in the head-group region, corresponding to an effective dielectric constant epsilon approximately or equal to 30, together with surface potentials of psi congruent to -100 and -150 mV at the carboxyl and amino group pKs, respectively. The transition temperature of dimyristoylphosphatidylserine-water mixtures decreases by approximately 4 degree C each water/lipid molecule added, reaching a limiting value at a water content of approximately 9-10 H2O/lipid molecule.

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“…The lowest energy monohydrated singly deprotonated phosphates arguably have an axial symmetric geometry of the hydrogen-bonded complex with a water molecule bridging the phosphinyl oxygens with stabilization energies between −20 and −28 kcal/mol depending on the level of calculations (without the BSSE correction). ,− The multihydrated phosphate groups were shown to contain mainly water molecules lying in the exterior of the phosphinyl triangle and singly hydrogen bonded to anionic oxygens . In accordance with previous studies, optimizations of the monohydrated phosphate species ( 7 and 8.1 ) (see Figure ) performed in this work yielded complexes with axial C 2 point-group symmetry as zero-order minima on the potential-energy surface.…”

Section: Silica and Phosphate Species In Vacuo In Complex With Sodium...mentioning

confidence: 99%

Adsorption of the Phosphate Groups on Silica Hydroxyls: An ab Initio Study

Murashov

Leszczyński

1999

J. Phys. Chem. A

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Adsorption of the phosphate groups on a silica surface is investigated by ab initio calculations of hydrogen-bond complexes of dihydrogen and dimethyl phosphate anions with orthosilicic acid. It is found that the phosphate groups can form strong hydrogen-bonded complexes with the silanols of the silica surface with stabilization energies of ca. −14 kcal/mol per hydrogen bond. The effect of the coordination of the phosphate species by water, orthosilicic acid, and a sodium cation on the geometry and stability of the -sc/-sc conformation is investigated through consideration of 2-fold axial symmetry complexes. Calculations suggest the reduction of the COPO torsion angle of the -sc/-sc conformation of the phosphodiester backbones upon adsorption of molecules containing these moieties on silica compared to the value of this angle found for phosphates in vacuo and in hydrated forms. Both the polarizing and electron density abstracting abilities of silanols cause electron density redistribution, giving rise to strengthening of the phosphoester P−O bonding, weakening of the phosphinyl PO and ester C−O bonding in adsorbed phosphate moieties. A very strong band at 3300 cm-1 appearing during the phosphate adsorption on the silanol hydroxyls is suggested for use as an indication of this phenomenon.

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Quantum-chemical and empirical calculations on phospholipids. III. Hydration of the dimethylphosphate anion

Cited by 34 publications

References 16 publications

Hydrogen Bonding of Water to Phosphatidylcholine in the Membrane As Studied by a Molecular Dynamics Simulation: Location, Geometry, and Lipid−Lipid Bridging via Hydrogen-Bonded Water

Hydrogen Bonding of Water to Phosphatidylcholine in the Membrane As Studied by a Molecular Dynamics Simulation: Location, Geometry, and Lipid−Lipid Bridging via Hydrogen-Bonded Water

Titration of the phase transition of phosphatidylserine bilayer membranes. Effects of pH, surface electrostatics, ion binding, and head-group hydration

Adsorption of the Phosphate Groups on Silica Hydroxyls: An ab Initio Study

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