20.500.12556/RUL-136231 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 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. lipid bilayer water transport proton transport water activity membrane mechanics lipidni dvosloj transport vode transport protona vodna aktivnost membranska mehanika true false true Angleški jezik Slovenski jezik Članek v reviji 2022-04-20 14:54:13 2022-04-20 14:54:14 2022-09-15 04:13:36 0000-00-00 00:00:00 2021 0 0 19 str. iss. 20, art. 11099 Vol. 22 Oct. 2021 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 577 1422-0067 10.3390/ijms222011099 81110275 ijms-22-11099-v2.pdf ijms-22-11099-v2.pdf 1 58C9438376F56AC2EA1D7AF87D0C1A0E 84816ea500e4fd30b5a5d87bede38c5ec45d59390dbfca1f30971733783ea5e0 1d1f740c-c0a9-11ec-8aca-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=155770 https://www.mdpi.com/1422-0067/22/20/11099 1 eaf43c19-c0a8-11ec-8aca-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=155769 Fakulteta za elektrotehniko Medicinska fakulteta 0 0 0