The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer
The molecular details of the passive water flux across the hydrophobic membrane interior are still a matter of debate. One of the postulated mechanisms is the spontaneous, water-filled pore opening, which facilitates the hydrophilic connection between aqueous phases separated by the membrane. In the...
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MDPI AG
2021-10-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/20/11099 |
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| author | Magdalena Przybyło Dominik Drabik Joanna Doskocz Aleš Iglič Marek Langner |
| author_facet | Magdalena Przybyło Dominik Drabik Joanna Doskocz Aleš Iglič Marek Langner |
| author_sort | Magdalena Przybyło |
| collection | DOAJ |
| description | The molecular details of the passive water flux across the hydrophobic membrane interior are still a matter of debate. One of the postulated mechanisms is the spontaneous, water-filled pore opening, which facilitates the hydrophilic connection between aqueous phases separated by the membrane. In the paper, we provide experimental evidence showing that the spontaneous lipid pore formation correlates with the membrane mechanics; hence, it depends on the composition of the lipid bilayer and the concentration of the osmotically active compound. Using liposomes as an experimental membrane model, osmotically induced water efflux was measured with the stopped-flow technique. Shapes of kinetic curves obtained at low osmotic pressure differences are interpreted in terms of two events: the lipid pore opening and water flow across the aqueous channel. The biological significance of the dependence of the lipid pore formation on the concentration difference of an osmotically active compound was illustrated by the demonstration that osmotically driven water flow can be accompanied by the dissipation of the pH gradient. The application of the Helfrich model to describe the probability of lipid pore opening was validated by demonstrating that the probability of pore opening correlates with the membrane bending rigidity. The correlation was determined by experimentally derived bending rigidity coefficients and probabilities of lipid pores opening. |
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| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T06:30:38Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-444c84abc0ce4fa8bb23a986898592ad2023-11-22T18:33:50ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-10-0122201109910.3390/ijms222011099The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid BilayerMagdalena Przybyło0Dominik Drabik1Joanna Doskocz2Aleš Iglič3Marek Langner4Department of Biomedical Engineering, Wroclaw University of Science and Technology, Grunwaldzki 13, 50-377 Wrocław, PolandDepartment of Biomedical Engineering, Wroclaw University of Science and Technology, Grunwaldzki 13, 50-377 Wrocław, PolandDepartment of Biomedical Engineering, Wroclaw University of Science and Technology, Grunwaldzki 13, 50-377 Wrocław, PolandLaboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, SloveniaDepartment of Biomedical Engineering, Wroclaw University of Science and Technology, Grunwaldzki 13, 50-377 Wrocław, PolandThe molecular details of the passive water flux across the hydrophobic membrane interior are still a matter of debate. One of the postulated mechanisms is the spontaneous, water-filled pore opening, which facilitates the hydrophilic connection between aqueous phases separated by the membrane. In the paper, we provide experimental evidence showing that the spontaneous lipid pore formation correlates with the membrane mechanics; hence, it depends on the composition of the lipid bilayer and the concentration of the osmotically active compound. Using liposomes as an experimental membrane model, osmotically induced water efflux was measured with the stopped-flow technique. Shapes of kinetic curves obtained at low osmotic pressure differences are interpreted in terms of two events: the lipid pore opening and water flow across the aqueous channel. The biological significance of the dependence of the lipid pore formation on the concentration difference of an osmotically active compound was illustrated by the demonstration that osmotically driven water flow can be accompanied by the dissipation of the pH gradient. The application of the Helfrich model to describe the probability of lipid pore opening was validated by demonstrating that the probability of pore opening correlates with the membrane bending rigidity. The correlation was determined by experimentally derived bending rigidity coefficients and probabilities of lipid pores opening.https://www.mdpi.com/1422-0067/22/20/11099lipid bilayerwater transportproton transportwater activitymembrane mechanics |
| spellingShingle | Magdalena Przybyło Dominik Drabik Joanna Doskocz Aleš Iglič Marek Langner The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer International Journal of Molecular Sciences lipid bilayer water transport proton transport water activity membrane mechanics |
| title | The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer |
| title_full | The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer |
| title_fullStr | The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer |
| title_full_unstemmed | The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer |
| title_short | The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer |
| title_sort | effect of the osmotically active compound concentration difference on the passive water and proton fluxes across a lipid bilayer |
| topic | lipid bilayer water transport proton transport water activity membrane mechanics |
| url | https://www.mdpi.com/1422-0067/22/20/11099 |
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