Oleic Acid Phase Behavior from Molecular Dynamics Simulations

Janke, J. Joel; Bennett, William F.; Tieleman, D. Peter

doi:10.1021/la501962n

Cited by 67 publications

(55 citation statements)

References 46 publications

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“…During the prandial period, this pH microclimate might also favor the ionization of LCFA released by lingual lipase from dietary TG. Although the pK a value of LCFA is always discussed (87,90), OLA monomers in water appear to be essentially ionized at neutral pH (87). This physicochemical characteristic might maintain LCFA in the extracellular environment of the TBC because the plasma membrane is poorly permeable to ionized LCFA, in contrast to their protonated forms (89).…”

Section: Influence Of the Salivary Environmentmentioning

confidence: 99%

Taste of Fat: A Sixth Taste Modality?

Besnard

Passilly-Degrace

Khan

2016

Physiological Reviews

203

170

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An attraction for palatable foods rich in lipids is shared by rodents and humans. Over the last decade, the mechanisms responsible for this specific eating behavior have been actively studied, and compelling evidence implicates a taste component in the orosensory detection of dietary lipids [i.e., long-chain fatty acids (LCFA)], in addition to textural, olfactory, and postingestive cues. The interactions between LCFA and specific receptors in taste bud cells (TBC) elicit physiological changes that affect both food intake and digestive functions. After a short overview of the gustatory pathway, this review brings together the key findings consistent with the existence of a sixth taste modality devoted to the perception of lipids. The main steps leading to this new paradigm (i.e., chemoreception of LCFA in TBC, cell signaling cascade, transfer of lipid signals throughout the gustatory nervous pathway, and their physiological consequences) will be critically analyzed. The limitations to this concept will also be discussed in the light of our current knowledge of the sense of taste. Finally, we will analyze the recent literature on obesity-related dysfunctions in the orosensory detection of lipids ("fatty" taste?), in relation to the overconsumption of fat-rich foods and the associated health risks.

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Section: Influence Of the Salivary Environmentmentioning

confidence: 99%

Taste of Fat: A Sixth Taste Modality?

Besnard

Passilly-Degrace

Khan

2016

Physiological Reviews

203

170

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“…Previous studies have shown that the apparent pKa of oleic acid in different surfactant and lipid mixtures ranges from 6.0 to 9.5. For example, the pKa of pure oleic acid vesicles is 8.0- 9.5 [27,42,43]. While when mixed with monoolein, the pKa was 6.0-7.0 [24].…”

Section: Dissociation Of Oleic Acid In Mixed 7:3 Dppc-oleic Acid Membmentioning

confidence: 99%

Interaction forces and membrane charge tunability: Oleic acid containing membranes in different pH conditions

Kurniawan

Suga

Kuhl

2017

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Oleic acid is known to interact with saturated lipid molecules and increase the fluidity of gel phase lipid membranes. In this work, the thermodynamic properties of mixed monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and oleic acid at the air-water interface were determined using Langmuir isotherms. The isotherm study revealed an attractive interaction between oleic acid and DPPC. The incorporation of oleic acid also monotonically decreased the elastic modulus of the monolayer indicative of higher fluidity with increasing oleic acid content. Using the surface force apparatus, intermembrane force-distance profiles were obtained for substrate supported DPPC membranes containing 30 mol% oleic acid at pH 5.8 and 7.4. Three different preparation conditions resulted in distinct force profiles. Membranes prepared in pH 5.8 subphase had a low number of nanoscopic defects ≤1% and an adhesion magnitude of~0.6 mN/m. A slightly higher defect density of 1-4% was found for membranes prepared in a physiological pH 7.4 subphase. The presence of the exposed hydrophobic moieties resulted in a higher adhesion magnitude of 2.9 mN/m. Importantly, at pH 7.4, some oleic acid deprotonates resulting in a long-range electrostatic repulsion. Even though oleic acid increased the DPPC bilayer fluidity and the number of defects, no membrane restructuring was observed indicating that the system maintained a stable configuration.

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“…We did this to obtain OA aggregates that were as similar as possible to the aggregates of the liprotide core, which consist of deprotonated OA . Increasing protonation first causes micelle elongation and eventually bilayer structure formation as determined previously with the MARTINI force field, and this is not likely to be relevant for the liprotides. To determine the amount of OA molecules per micelle to use in this study we performed a CG MD simulation on a solution of 500 OA molecules in water (0.06 wt %) over the course of 1 μs.…”

Section: Resultsmentioning

confidence: 60%

Role of Charge and Hydrophobicity in Liprotide Formation: A Molecular Dynamics Study with Experimental Constraints

et al. 2018

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Bovine α-lactalbumin (aLA) and oleate (OA) form a complex that has been intensively studied for its tumoricidal activity. Small-angle X-ray scattering (SAXS) has revealed that this complex consists of a lipid core surrounded by partially unfolded protein. We call this type of complex a liprotide. Little is known of the molecular interactions between OA and aLA, and no technique has so far provided any high-resolution structure of a liprotide. Here we have used coarse-grained (CG) molecular dynamics (MD) simulations, isothermal titration calorimetry (ITC) and SAXS to investigate the interactions between aLA and OA during the process of liprotide formation. With ITC we found that the strongest enthalpic interactions occurred at a molar ratio of 12.0±1.4:1 OA/aLA. Liprotides formed between OA and aLA at several OA/aLA ratios in silico were stable both in CG and in all-atom simulations. From the simulated structures we calculated SAXS spectra that show good agreement with experimentally measured patterns of matching liprotides. The simulations showed that aLA assumes a molten globular (MG) state, exposing several hydrophobic patches involved in interactions with OA. Initial binding of aLA to OA occurs in an area of aLA in which a high amount of positive charge is located, and only later do hydrophobic interactions become important. The results reveal how unfolding of aLA to expose hydrophobic residues is important for complex formation between aLA and OA. Our findings suggest a general mechanism for liprotide formation and might explain the ability of a large number of proteins to form liprotides with OA.

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Oleic Acid Phase Behavior from Molecular Dynamics Simulations

Cited by 67 publications

References 46 publications

Taste of Fat: A Sixth Taste Modality?

Taste of Fat: A Sixth Taste Modality?

Interaction forces and membrane charge tunability: Oleic acid containing membranes in different pH conditions

Role of Charge and Hydrophobicity in Liprotide Formation: A Molecular Dynamics Study with Experimental Constraints

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