Micropolarities of lipid bilayers and micelles. 3. Effect of monovalent ions on the dielectric constant of the water-membrane interface of unilamellar phosphatidylcholine vesicles

Lessard, J.G.; Fragata, M.

doi:10.1021/j100277a022

Cited by 44 publications

(24 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…e is about 30 at the location of the carboxy groups of the fatty acid chain [150]. Other measurements averaged to e of 30 to 33 at the interface between polar head groups and the hydrocarbon core [176]. The e of the absorption site of pentachlorophenoxide, the deprotonated species of PCP, is approximately 8.4 for PC membranes and 18 for the negatively charged PG membranes [177].…”

Section: Site Of Interaction Of Hiocs With Membranesmentioning

confidence: 98%

Chemical Speciation of Organics and of Metals at Biological Interphases

Escher

Sigg

2004

Physicochemical Kinetics and Transport at Biointerfaces

View full text Add to dashboard Cite

Section: Site Of Interaction Of Hiocs With Membranesmentioning

confidence: 98%

Chemical Speciation of Organics and of Metals at Biological Interphases

Escher

Sigg

2004

Physicochemical Kinetics and Transport at Biointerfaces

View full text Add to dashboard Cite

“…The reagents for fatty acid analyses (see below) were from Pierce Chemical Company. CaC1;, MgC12 and NaC1 were from Sigma Chemical Company (St. Louis, MO) and were purified as described in Lessard and Fragata (1986); in brief, each salt was washed successively in three different organic solvents (methanol, benzene, chloroform), then dried at 150 °C for 24 h to remove any residual adsorbed solvent. Galactose was obtained from Fisher Scientific Company (Fair Lawn, N J) and shown to be a mixture of c~-and fi-anomers on the basis of FTIR spectroscopic analyses of the type 2a and 2b vibrational bands around 837 and 893 cm-1, respectively (see Parker 1971;Tu 1982).…”

Section: Chemicalsmentioning

confidence: 99%

“…For example, the diffusion of the ion out of the water-lipid interface where e~ is from 25 to 32 (cf. Lessard and Fragata 1986) into the bulk aqueous phase (e2 ~ 78) is energetically favourable, i.e. A# is between -27 and -18 kJ mol-1 which is a range that lies within the strength span of most hydrogen bonds, that is, from 10 to 40 kJ tool -1 (Israelachvili 1985).…”

Section: A# = 8n~o a -'mentioning

confidence: 99%

Fourier transform infrared spectroscopic study of ion binding and intramolecular interactions in the polar head of digalactosyldiacylglycerol

Menikh

Fragata

1993

Eur Biophys J

Self Cite

View full text Add to dashboard Cite

Lipid bilayers composed of digalactosyldiacylglycerol (DGDG), that is, Galp alpha 1-6Galp beta 1-3DAG, a non-ionic lipid of the thylakoid membrane of chloroplasts, aggregate in aqueous media containing mono- and divalent cations in amounts above a threshold concentration (Ct) of about 1.0, 4.7 and 10.0 mM for Ca2+, Mg2+ and Na+, respectively. In this work, we found that above Ct the DGDG membranes do not undergo fusion and that the aggregation can be reversed or disrupted. This means that the perturbation induced by the salts results from adsorption, or complexation of the ions in the polar head of DGDG. To investigate this question, we used Fourier transform infrared (FTIR) spectroscopy to identify the molecular sites in DGDG which are modified by interaction, or adduct formation with CaCl2, MgCl2 and NaCl. We also determined whether the ions affect the intramolecular hydrogen bonding between the sn2 ester C = O and the carbon-6 of the alpha-anomer of galactose (Gal). The major conclusions are: (i) the salts do not affect, at least directly, the ester carbonyl region of DGDG, (ii) the most probable sites of binding, or adsorption, for the ions are the ring oxygen, and (iii) the ring hydroxyls are the sites of either ion complexation or intra- and intermolecular H-bonding in interacting DGDG membranes. Within this framework, the complexation of the ions with Gal might induce total or partial dehydration of the galactolipid headgroup and thus provides the means to overcome the repulsive hydration forces that hinder aggregation of the DGDG membranes.

show abstract

“…This concentration was chosen to maximize effects of the salt on the relative water permittivity while minimizing direct effects on the membrane. In bulk solution, 1 M NaCl reduces water permittivity by about 14%, and at the membrane surface, the effect is reported to be even larger (22% reduction) [25,26]. This reduction would be expected to attenuate the solvent relaxation effect by more than 0.1 GP units depending on the distance between responsible waters and the depth of penetration of the salt.…”

Section: Effects Of Saltsmentioning

confidence: 96%

Relationships between membrane water molecules and Patman equilibration kinetics at temperatures far above the phosphatidylcholine melting point

Vaughn

Bell

Gibbons

et al. 2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

View full text Add to dashboard Cite

The naphthalene-based fluorescent probes Patman and Laurdan detect bilayer polarity at the level of the phospholipid glycerol backbone. This polarity increases with temperature in the liquid-crystalline phase of phosphatidylcholines and was observed even 90°C above the melting temperature. This study explores mechanisms associated with this phenomenon. Measurements of probe anisotropy and experiments conducted at 1M NaCl or KCl (to reduce water permittivity) revealed that this effect represents interactions of water molecules with the probes without proportional increases in probe mobility. Furthermore, comparison of emission spectra to Monte Carlo simulations indicated that the increased polarity represents elevation in probe access to water molecules rather than increased mobility of relevant bilayer waters. Equilibration of these probes with the membrane involves at least two steps which were distinguished by the membrane microenvironment reported by the probe. The difference in those microenvironments also changed with temperature in the liquid-crystalline phase in that the equilibrium state was less polar than the initial environment detected by Patman at temperatures near the melting point, more polar at higher temperatures, and again less polar as temperature was raised further. Laurdan also displayed this level of complexity during equilibration, although the relationship to temperature differed quantitatively from that experienced by Patman. This kinetic approach provides a novel way to study in molecular detail basic principles of what happens to the membrane environment around an individual amphipathic molecule as it penetrates the bilayer. Moreover, it provides evidence of unexpected and interesting membrane behaviors far from the phase transition.

show abstract

Micropolarities of lipid bilayers and micelles. 3. Effect of monovalent ions on the dielectric constant of the water-membrane interface of unilamellar phosphatidylcholine vesicles

Cited by 44 publications

References 3 publications

Chemical Speciation of Organics and of Metals at Biological Interphases

Chemical Speciation of Organics and of Metals at Biological Interphases

Fourier transform infrared spectroscopic study of ion binding and intramolecular interactions in the polar head of digalactosyldiacylglycerol

Relationships between membrane water molecules and Patman equilibration kinetics at temperatures far above the phosphatidylcholine melting point

Contact Info

Product

Resources

About