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Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane

Lateral transport and release of protons at the water–membrane interface play crucial roles in cell bioenergetics. Therefore, versatile techniques need to be developed for investigating as well as clarifying the main features of these processes at the molecular level. Here, we experimentally measure...

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Autores principales: Sokolov, Valerij S., Tashkin, Vsevolod Yu., Zykova, Darya D., Kharitonova, Yulia V., Galimzyanov, Timur R., Batishchev, Oleg V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10456422/
https://www.ncbi.nlm.nih.gov/pubmed/37623783
http://dx.doi.org/10.3390/membranes13080722
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author Sokolov, Valerij S.
Tashkin, Vsevolod Yu.
Zykova, Darya D.
Kharitonova, Yulia V.
Galimzyanov, Timur R.
Batishchev, Oleg V.
author_facet Sokolov, Valerij S.
Tashkin, Vsevolod Yu.
Zykova, Darya D.
Kharitonova, Yulia V.
Galimzyanov, Timur R.
Batishchev, Oleg V.
author_sort Sokolov, Valerij S.
collection PubMed
description Lateral transport and release of protons at the water–membrane interface play crucial roles in cell bioenergetics. Therefore, versatile techniques need to be developed for investigating as well as clarifying the main features of these processes at the molecular level. Here, we experimentally measured the kinetics of binding of protons released from the photoactivated compound sodium 2-methoxy-5-nitrophenyl sulfate (MNPS) at the surface of a bilayer lipid membrane (BLM). We developed a theoretical model of this process describing the damage of MNPS coupled with the release of the protons at the membrane surface, as well as the exchange of MNPS molecules and protons between the membrane and solution. We found that the total change in the boundary potential difference across the membrane, ∆ϕ(b), is the sum of opposing effects of adsorption of MNPS anions and release of protons at the membrane–water interface. Steady-state change in the ∆ϕ(b) due to protons decreased with the concentration of the buffer and increased with the pH of the solution. The change in the concentration of protons evaluated from measurements of ∆ϕ(b) was close to that in the unstirred water layer near the BLM. This result, as well as rate constants of the proton exchange between the membrane and the bulk solution, indicated that the rate-limiting step of the proton surface to bulk release is the change in the concentration of protons in the unstirred layer. This means that the protons released from MNPS remain in equilibrium between the BLM surface and an adjacent water layer.
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spelling pubmed-104564222023-08-26 Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane Sokolov, Valerij S. Tashkin, Vsevolod Yu. Zykova, Darya D. Kharitonova, Yulia V. Galimzyanov, Timur R. Batishchev, Oleg V. Membranes (Basel) Article Lateral transport and release of protons at the water–membrane interface play crucial roles in cell bioenergetics. Therefore, versatile techniques need to be developed for investigating as well as clarifying the main features of these processes at the molecular level. Here, we experimentally measured the kinetics of binding of protons released from the photoactivated compound sodium 2-methoxy-5-nitrophenyl sulfate (MNPS) at the surface of a bilayer lipid membrane (BLM). We developed a theoretical model of this process describing the damage of MNPS coupled with the release of the protons at the membrane surface, as well as the exchange of MNPS molecules and protons between the membrane and solution. We found that the total change in the boundary potential difference across the membrane, ∆ϕ(b), is the sum of opposing effects of adsorption of MNPS anions and release of protons at the membrane–water interface. Steady-state change in the ∆ϕ(b) due to protons decreased with the concentration of the buffer and increased with the pH of the solution. The change in the concentration of protons evaluated from measurements of ∆ϕ(b) was close to that in the unstirred water layer near the BLM. This result, as well as rate constants of the proton exchange between the membrane and the bulk solution, indicated that the rate-limiting step of the proton surface to bulk release is the change in the concentration of protons in the unstirred layer. This means that the protons released from MNPS remain in equilibrium between the BLM surface and an adjacent water layer. MDPI 2023-08-08 /pmc/articles/PMC10456422/ /pubmed/37623783 http://dx.doi.org/10.3390/membranes13080722 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Sokolov, Valerij S.
Tashkin, Vsevolod Yu.
Zykova, Darya D.
Kharitonova, Yulia V.
Galimzyanov, Timur R.
Batishchev, Oleg V.
Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane
title Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane
title_full Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane
title_fullStr Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane
title_full_unstemmed Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane
title_short Electrostatic Potentials Caused by the Release of Protons from Photoactivated Compound Sodium 2-Methoxy-5-nitrophenyl Sulfate at the Surface of Bilayer Lipid Membrane
title_sort electrostatic potentials caused by the release of protons from photoactivated compound sodium 2-methoxy-5-nitrophenyl sulfate at the surface of bilayer lipid membrane
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10456422/
https://www.ncbi.nlm.nih.gov/pubmed/37623783
http://dx.doi.org/10.3390/membranes13080722
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