The Free Energy of Hydration of Ions and the Electrostriction of the Solvent

Webb, Timothy

doi:10.1021/ja01421a013

Cited by 112 publications

(44 citation statements)

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“…However, this important observation was not always analyzed with a clear microscopic perspective. Mehler and coworkers [76,78] argued, correctly, that e eff ðrÞ is a sigmoid function with a large value at relatively short distances based on classical studies of eðrÞ in water [79][80][81]. Similarly, it has been assumed by Jonsson and coworkers [77] that electrostatic interactions in proteins can be described by using a large e eff for charge-charge interactions.…”

Section: The Meaning and Use Of The Protein Dielectric Constantmentioning

confidence: 96%

Electrostatics of Proteins: Principles, Models and Applications

Braun‐Sand¹,

Warshel²

2005

Protein Folding Handbook

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Section: The Meaning and Use Of The Protein Dielectric Constantmentioning

confidence: 96%

Electrostatics of Proteins: Principles, Models and Applications

Braun‐Sand¹,

Warshel²

2005

Protein Folding Handbook

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“…A major issue in the theoretical estimate was the assumption of the bulk dielectric constant [77] close to the electrode-electrolyte interface. For instance, the large electric field at the surface (due to the potential drop over a size scale of an ion) implies the necessity for considering orientational effects on the electrolyte constituted water molecules, in addition to enhanced polarization [78]. Consequently, the e r may be considerably reduced to as low as 4.7 for ion-electrode distances of the order of 0.1 nm and to 7.8 for 0.2 nm (note that the radius of the OH À ion is 0.155 nm).…”

Section: The Double Layermentioning

confidence: 99%

Charge transfer and storage in nanostructures

Bandaru

Yamada

Narayanan

et al. 2015

Materials Science and Engineering: R: Reports

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“…The strong orientation of the proximal solvent dipoles implies that they are no longer able to respond linearly to the external electric field from the solute. This widely studied effect has been called dielectric saturation (3,(10)(11)(12)(13)(14)(15) since the 1920s when Debye developed the theoretical Langevin-Debye (LD) model to describe dielectric saturation by treating the solvent as a continuous distribution of point, polarizable dipoles and by allowing the dipole reorientation to depend on the self-consistent, many-body (and hence nonlinear response) local field generated by all other solvent dipoles (16). Subsequent extension of the LD model by Onsager (17) and then by Kirkwood and Frohlich (18) includes the influence of dipoledipole correlations and local solvent density changes near the solute, respectively.…”

mentioning

confidence: 99%

Influence of nonlinear electrostatics on transfer energies between liquid phases: Charge burial is far less expensive than Born model

Gong

Hocky

Freed

2008

Proc. Natl. Acad. Sci. U.S.A.

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The widely used Born model describes the electrostatic response of continuous media using static dielectric constants. However, when applied to a liquid environment, a comparison of Born model predictions with experimental values (e.g., transfer free energies and pK a shifts) found that agreement is only achieved by using physically unrealistic dielectric constants for proteins, lipids, etc., and/or equally unrealistic atomic radii. This leads to questions concerning the physical origins for this failure of the Born model. We partially resolve this question by applying the Langevin-Debye (LD) model of a continuous distribution of point, polarizable dipoles, a model that contains an added dependence of the electrostatic response on the solvent's optical dielectric constant and both gas-and liquid-phase dipole moments, features absent in the Born model to which the LD model reduces for weak fields. The LD model is applied to simple representations of three biologically relevant systems: (i) globular proteins, (ii) lipid bilayers, and (iii) membrane proteins. The linear Born treatment greatly overestimates both the self-energy and the transfer free energy from water to hydrophobic environments (e.g., a protein interior). By using the experimental dielectric constant, the energy cost of charge burial in either globular or membrane proteins of the Born model is reduced by almost 50% with the nonlinear theory as is the pKa shift, and the shifts agree well with experimental trends.Langevin-Debye model ͉ pKa shifts ͉ orientational polarization ͉ dielectric saturation and screening T he interaction of molecules and ions with various solvents is of importance in many physical, chemical, and biological systems. For example, electrostatics strongly influence enzyme catalysis, electron transfer, proton transport, ion channels, photo-activation, and ligand binding (1). Macroscopic dielectric continuum models are frequently invoked to describe solvation, especially in large biological systems where computations (using molecular mechanics, molecular dynamics, quantum mechanics, or combinations thereof) with explicit solvent molecules become prohibitive for many systems of physical interest. Although continuum models neglect certain microscopic details, the hope is to reduce the errors sufficiently by correctly describing the physics (2). Unfortunately, serious limitations have long been evident with one of the most popular models, the Born model (and the equivalent use of the Poisson equation), in which the solvent is characterized solely by the static dielectric constant. For example, Sandberg and Edholm concluded that the Born model introduces errors as large as 1,000 KJ/mol when used to predict the hydration energies of multivalent ions (3). The Born model is also frequently applied in evaluating the transfer free energy of ionizable groups between water and hydrophobic media, such as proteins and lipids, thereby predicting the pK a shift of a buried ionizable group. Multiple experiments and theoretical predictions agree tha...

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The Free Energy of Hydration of Ions and the Electrostriction of the Solvent

Cited by 112 publications

References 1 publication

Electrostatics of Proteins: Principles, Models and Applications

Electrostatics of Proteins: Principles, Models and Applications

Charge transfer and storage in nanostructures

Influence of nonlinear electrostatics on transfer energies between liquid phases: Charge burial is far less expensive than Born model

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