Sulfate Anion in Water: Model Structural, Thermodynamic, and Dynamic Properties

Cannon, W. Roger; Pettitt, B. Montgomery; McCammon, J. Andrew

doi:10.1021/j100075a027

Cited by 186 publications

(190 citation statements)

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“…32 Force field parameters for the IL cation were obtained from the work of Cadena and Maginn, 33 while those for the IL anion were taken from those developed by Canongia Lopes and Pádua. 34 Lennard-Jones parameters for Na + and Cl -were taken from Jensen and Jorgensen, 35 while those for SO 4 2-were from the work of Cannon et al 36 In the absence of a force field for SCN -, an equivalent salting-out anion was studied, namely ClO 4 -, whose parameters were obtained from the work of Cadena and Maginn. 33 Simulations were conducted at 298.15 K using a Langevin thermostat applied to all heavy atoms.…”

Section: Molecular Dynamics Simulation Methodsmentioning

confidence: 99%

¹H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena

et al. 2010

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By employing 1 H NMR spectroscopy and molecular simulations, we provide an explanation for recent observations that the aqueous solubilities of ionic liquids exhibit salting-out to salting-in regimes upon addition of distinct inorganic salt ions. Using a typical ionic liquid [1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide], we observed the existence of preferential specific interactions between the low electrical charge density ("apolar moiety") parts of the ionic liquid cation and the inorganic salts. These a priori unexpected interactions become increasingly favorable as one moves from salting-out to salting-in effects. More specifically, this interpretation is validated by distinct aqueous solution 1 H NMR data shifts in the ionic liquid cation upon inorganic salt addition. These shifts, which are well noted in the terminal and preterminal hydrogens of the alkyl chain appended to the imidazolium ring, correlate quantitatively with solubility data, both for cases where the nature of inorganic salt is changed, at constant concentration, and for those where the concentration of a given inorganic salt is varied. Molecular simulations have also been performed permitting us to garner a broader picture of the underlying mechanism and structure of this complex solvation phenomenon. These findings can now be profitably used to anticipate solution behavior upon inorganic salt addition well beyond the specificity of the ionic liquid solutions, i.e., for a diversity of distinct solutes differing in chemical nature.

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Section: Molecular Dynamics Simulation Methodsmentioning

confidence: 99%

¹H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena

et al. 2010

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“…The dynamic behavior of the SO',--protein system near the active site is expected to be limited based on crystallographic temperature factors below 0.08 nm2 for atoms in this region. For comparison, binding studies were done with the molecular mechanics potential functions in which SO:- (Cannon et al, 1994) and OPLS potentials were used. Energies and intermolecular distances were similar for C H 3 0 H .…”

Section: Resultsmentioning

confidence: 99%

“…This latter calculation also included a counterpoise correction (Boys & Bernardi, 1970) for the basis set superposition error. Although electron correlation is important for many systems, previous work (Cannon et al, 1994) done on sulfate complexes suggests that errors due to basis set superposition errors are more significant. The CH30H.SO:-and CH,SH.SO:-complexes were held in a monodentate binding mode in which CH30H and CH3SH approach the anion such that the interacting hydrogen and heteroatom are colinear with a sulfate oxygen and sulfur, and the methyl carbon is coplanar with the same sulfate oxygen, sulfur, and a second sulfate oxygen as shown in Figure 1.…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

“…Only the intermolecular distances between the species were optimized. The tetrahedral sulfate geometry utilized here and in the simulations used a bond length of 0.14898 nm (Cannon et al, 1994). The geometries for CH30H and CH3SH were from previous optimizations at the HF/6-3 1 + G(d) level (Jorgensen & Briggs, 1989).…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

“…As noted previously (Smith et al, 1991) and also observed in our work, this is necessary in order to have proper energetics between these charged groups and the polar amino hydrogens. Sulfate parameters have been developed previously (Cannon et al, 1994). Calculations were done with ARGOS software (Straatsma & McCammon, 1990).…”

Section: Free Energy Simulationsmentioning

confidence: 99%

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Conservative and nonconservative mutations in proteins: Anomalous mutations in a transport receptor analyzed by free energy and quantum chemical calculations

et al. 1995

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Experimental studies on a bacterial sulfate receptor have indicated anomalous relative binding affinities for the mutations Ser,,o + Cys, Ser,30 + Gly, and Ser,,, + Ala. The loss of affinity for sulfate in the former mutation was previously attributed to a greater steric effect on the part of the Cys side chain relative to the Ser side chain, whereas the relatively small loss of binding affinity for the latter two mutations was attributed to the loss of a single hydrogen bond. In this report we present quantum chemical and statistical thermodynamic studies of these mutations. Qualitative results from these studies indicate that for the Ser,,, -+ Cys mutation the large decrease in binding affinity is in part caused by steric effects, but also significantly by the differential work required to polarize the Cys thiol group relative to the Ser hydroxyl group. The Gly mutant cobinds a water molecule in the same location as the Ser side chain resulting in a relatively small decrease in binding affinity. Results for the Ala mutant are in disagreement, with experimental results but are likely to be limited by insufficient sampling of configuration space due to physical constraints applied during the simulation.Keywords: binding proteins; molecular recognition; polarization effects; protein engineering; simulation Site-directed mutagenesis has become one of the most powerful and significant tools for molecular biology, biochemistry, and biotechnology. Protein engineering, binding studies of drugs and receptors, and mechanistic studies in enzymology and molecular biology all depend on correct interpretations of mutagenesis work. In fact, accurate interpretations can be the basis for considerable investments in time and money by researchers in academia and industry.Several classes of mutations are considered to be relatively conservative, that is, substitution of one amino acid residue for a homologous one (such as isoleucine for leucine, aspartate for -Reprint requests to: J.

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Efflorescence upon humidification? X‐ray microspectroscopic in situ observation of changes in aerosol microstructure and phase state upon hydration

Pöhlker

Saturno

Krüger

et al. 2014

Geophysical Research Letters

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The phase and mixing state of atmospheric aerosols is a central determinant of their properties and thus their role in atmospheric cycling and climate. Particularly, the hygroscopic response of aerosol particles to relative humidity (RH) variation is a key aspect of their atmospheric life cycle and impacts. Here we applied X-ray microspectroscopy under variable RH conditions to internally mixed aerosol particles from the Amazonian rain forest collected during periods with anthropogenic pollution. Upon hydration, we observed substantial and reproducible changes in particle microstructure, which appear as mainly driven by efflorescence and recrystallization of sulfate salts. Multiple solid and liquid phases were found to coexist, especially in intermediate humidity regimes. We show that X-ray microspectroscopy under variable RH is a valuable technique to analyze the hygroscopic response of individual ambient aerosol particles. Our initial results underline that RH changes can trigger strong particle restructuring, in agreement with previous studies on artificial aerosols.

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Sulfate Anion in Water: Model Structural, Thermodynamic, and Dynamic Properties

Cited by 186 publications

References 10 publications

¹H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena

¹H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena

Conservative and nonconservative mutations in proteins: Anomalous mutations in a transport receptor analyzed by free energy and quantum chemical calculations

Efflorescence upon humidification? X‐ray microspectroscopic in situ observation of changes in aerosol microstructure and phase state upon hydration

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Sulfate Anion in Water: Model Structural, Thermodynamic, and Dynamic Properties

Cited by 186 publications

References 10 publications

1H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena

1H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena

Conservative and nonconservative mutations in proteins: Anomalous mutations in a transport receptor analyzed by free energy and quantum chemical calculations

Efflorescence upon humidification? X‐ray microspectroscopic in situ observation of changes in aerosol microstructure and phase state upon hydration

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Product

Resources

About

¹H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena

¹H NMR and Molecular Dynamics Evidence for an Unexpected Interaction on the Origin of Salting-In/Salting-Out Phenomena