Molecular Dynamics Simulation of Aerosol-OT Reverse Micelles

Chowdhary, Janamejaya; Ladanyi, Branka M.

doi:10.1021/jp906915q

Cited by 124 publications

(197 citation statements)

References 74 publications

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“…The IR spectra for water computed from those simulations, where the RMs exhibited nonspherical geometries, were found to be in good agreement with experiment. 44,45 Finally, Tian and Garcia 46 employed molecular dynamics simulations to study the self-assembly of AOT/water RMs (w 0 = 6 and 11) in isooctane. The RM systems included one helical AK4 (NH + 3 -YG(AKAAA) 4 AG-COO − ) peptide.…”

Section: B the Nature Of A Reverse Micelle Environment In Peptide Comentioning

confidence: 99%

Protein folding in a reverse micelle environment: The role of confinement and dehydration

Martinez

Domı́nguez

Rivera

et al. 2011

The Journal of Chemical Physics

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Characterization of the molecular interactions that stabilize the folded state of proteins including hydrogen bond formation, solvation, molecular crowding, and interaction with membrane environments is a fundamental goal of theoretical biophysics. Inspired by recent experimental studies by Gai and co-workers, we have used molecular dynamics simulations to explore the structure and dynamics of the alanine-rich AKA 2 peptide in bulk solution and in a reverse micelle environment. The simulated structure of the reverse micelle shows substantial deviations from a spherical geometry. The AKA 2 peptide is observed to (1) remain in a helical conformation within a spherically constrained reverse micelle and (2) partially unfold when simulated in an unconstrained reverse micelle environment, in agreement with experiment. While aqueous solvation is found to stabilize the N-and C-termini random coil portions of the peptide, the helical core region is stabilized by significant interaction between the nonpolar surface of the helix and the aliphatic chains of the AOT surfactant. The results suggest an important role for nonpolar peptide-surfactant and peptide-lipid interactions in stabilizing helical geometries of peptides in reverse micelle environments.

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Section: B the Nature Of A Reverse Micelle Environment In Peptide Comentioning

confidence: 99%

Protein folding in a reverse micelle environment: The role of confinement and dehydration

Martinez

Domı́nguez

Rivera

et al. 2011

The Journal of Chemical Physics

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“…any of the four oxygen atoms in the headgroup), but we found that the sulphur atom provides a better definition of the intrinsic profile, which features stronger oscillations in this case, making possible the identification of the water layers solvating different atoms. A similar choice has been made in recent work on simulations of AOT reverse micelles (Chowdhary & Ladanyi 2009).…”

Section: Methodology (A) Force-field and Computer Simulation Detailsmentioning

confidence: 99%

The intrinsic interfacial structure of ionic surfactant monolayers at water–oil and water–vapour interfaces

et al. 2011

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Using computer simulations, we investigate the interfacial structure of sodium dodecyl sulphate (SDS) monolayers adsorbed at the water surface and water-oil interfaces. Using an algorithm that removes the averaging effect of the capillary waves, we obtain a detailed view of the solvation structure of water around the monolayer. We investigate surface concentrations between 45 and 33 Å 2 per surfactant, which are near experimental conditions corresponding to the critical micellar concentration and the formation of Newton black films. The surfactants induce a layering structure in water, which disappears at approximately 1 nm from the monolayer plane. The water molecules exhibit a preferred orientation with the dipoles pointing towards the monolayer. The orientational order decays slowly, but it does not influence the hydrogen bond structure of water, which is significantly disrupted in the interfacial region only. These structural changes are qualitatively the same in SDS-water and oil-SDS-water interfaces. In the latter case, we find a small degree of penetration of oil in the monolayer (between 0.2 and 0.25 molecules per SDS). This small penetration has a measurable effect on the monolayer, which increases its thickness by approximately 10 per cent. The bending modulus of the SDS monolayers is of the order of the thermal energy, k B T .

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“…[32][33][34][35][36][37][38][39] In addition, the reorientational and diffusional dynamics are slowed, often dramatically. 10,[39][40][41][42][43][44][45][46][47][48][49] The effect of nanoscale confinement on water is more limited to the interfacial region compared to other liquids despite the fact that it is a networked liquid.…”

Section: Introductionmentioning

confidence: 99%

Simulations of the infrared, Raman, and 2D-IR photon echo spectra of water in nanoscale silica pores

Burris

Laage

Thompson

2016

The Journal of Chemical Physics

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Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for water confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D 2 O is considered. An empirical mapping approach is used to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of water in mesoporous silica reported in the literature. The key effect of confinement on the water spectrum is a vibrational blueshift for OH groups that are closest to the pore interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. The simulated spectra indicates that it should be possible to probe the slower spectral diffusion of confined water compared to the bulk liquid by analysis of the 2D-IR spectra. Published by AIP Publishing. [http://dx

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Molecular Dynamics Simulation of Aerosol-OT Reverse Micelles

Cited by 124 publications

References 74 publications

Protein folding in a reverse micelle environment: The role of confinement and dehydration

Protein folding in a reverse micelle environment: The role of confinement and dehydration

The intrinsic interfacial structure of ionic surfactant monolayers at water–oil and water–vapour interfaces

Simulations of the infrared, Raman, and 2D-IR photon echo spectra of water in nanoscale silica pores

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