Experimental determination of aqueous sodium-acetate dissociation constants at temperatures from 20 to 240°C

Fournier, Patricia; Oelkers, Eric H.; Gout, Robert; Pokrovski, Gleb S.

doi:10.1016/s0009-2541(98)00071-0

Cited by 36 publications

(36 citation statements)

References 39 publications

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“…Our results underline some of what is already known about the association of sodium and potassium ions with polycarboxylates, and support further suggestions that have until now lacked experimental confirmation. Although isolated low-pK a carboxylate groups show a 2:1 preference for K + over Na + , [20] the reverse is found here for the micelles. We attribute this to the known preference for sodium in polycarboxylates.…”

Section: Resultsmentioning

confidence: 44%

Counterions Control the Self‐Assembly of Structurally Persistent Micelles: Theoretical Prediction and Experimental Observation of Stabilization by Sodium Ions

Jäger

Hirsch

Schade

et al. 2009

Chemistry A European J

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We show by molecular-dynamics (MD) simulations and cryo-transmission electron microscopy (cryo-TEM) experiments that the size and form of structurally persistent micelles formed by the T-shaped amphiphile 1 are controlled by the counterions. The two techniques reveal that the micelles are specifically stabilized by sodium counterions relative to potassium ions. Both the simulations and the cryo-TEM experiments suggest that the micelles are stabilized by strongly conserved hydrated contact ion pairs with sodium counterions but not with potassium ions. We suggest that the TEM is observing local high density due to hydrated carboxylate/sodium ion pairs at the surface of the micelle. A high concentration of such structures is found in MD simulations with sodium counterions, but not with potassium.

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Section: Resultsmentioning

confidence: 44%

Counterions Control the Self‐Assembly of Structurally Persistent Micelles: Theoretical Prediction and Experimental Observation of Stabilization by Sodium Ions

Jäger

Hirsch

Schade

et al. 2009

Chemistry A European J

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“…K D estimates can be compared to different available experimental values of 1.17–1.51 M (Robinson and Stokes, 2002) and 1.0–1.6 M (Fournier et al, 1998) using potentiometry in dilute sodium acetate solutions at 298K (although K D values below 1M are seen at elevated temperatures [Fournier et al, 1998]). The value of 0.9 ± 0.2 M for standard CHARMM27* is at the lower end of the range, while the NBFIX r min = 3.19 Å value of 1.8 ± 0.2 M is at the top end of the range.…”

Section: Sodium-carboxylate Interaction Testsmentioning

confidence: 99%

A selectivity filter at the intracellular end of the acid-sensing ion channel pore

Lynagh

Flood

Boiteux

et al. 2017

eLife

132

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Increased extracellular proton concentrations during neurotransmission are converted to excitatory sodium influx by acid-sensing ion channels (ASICs). 10-fold sodium/potassium selectivity in ASICs has long been attributed to a central constriction in the channel pore, but experimental verification is lacking due to the sensitivity of this structure to conventional manipulations. Here, we explored the basis for ion selectivity by incorporating unnatural amino acids into the channel, engineering channel stoichiometry and performing free energy simulations. We observed no preference for sodium at the “GAS belt” in the central constriction. Instead, we identified a band of glutamate and aspartate side chains at the lower end of the pore that enables preferential sodium conduction.DOI: http://dx.doi.org/10.7554/eLife.24630.001

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“…This choice also considers that the potentiometric method, used to collect the reference experimental data, identifies both CIP and SIP complexes as associated species. 56…”

Section: Calculation Of the Association Constantmentioning

confidence: 99%

Interaction of Charged Amino-Acid Side Chains with Ions: An Optimization Strategy for Classical Force Fields

et al. 2014

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Many well-established classical biomolecular force fields, fitted on the solvation properties of single ions, do not necessarily describe all the details of ion pairing accurately, especially for complex polyatomic ions. Depending on the target application, it might not be sufficient to reproduce the thermodynamics of ion pairing, but it may also be necessary to correctly capture structural details, such as the coordination mode. In this work, we analyzed how classical force fields can be optimized to yield a realistic description of these different aspects of ion pairing. Given the prominent role of the interactions of negatively charged amino-acid side chains and divalent cations in many biomolecular systems, we chose calcium acetate as a benchmark system to devise a general optimization strategy that we applied to two popular force fields, namely, GROMOS and OPLS-AA. Using experimental association constants and first-principles molecular dynamics simulations as a reference, we found that small modifications of the van der Waals ion-ion interaction parameters allow a systematic improvement of the essential thermodynamic and structural properties of ion pairing.

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Experimental determination of aqueous sodium-acetate dissociation constants at temperatures from 20 to 240°C

Cited by 36 publications

References 39 publications

Counterions Control the Self‐Assembly of Structurally Persistent Micelles: Theoretical Prediction and Experimental Observation of Stabilization by Sodium Ions

Counterions Control the Self‐Assembly of Structurally Persistent Micelles: Theoretical Prediction and Experimental Observation of Stabilization by Sodium Ions

A selectivity filter at the intracellular end of the acid-sensing ion channel pore

Interaction of Charged Amino-Acid Side Chains with Ions: An Optimization Strategy for Classical Force Fields

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