| Autor: |
Ewald Weichselbaum, Maria Österbauer, Denis G. Knyazev, Oleg V. Batishchev, Sergey A. Akimov, Trung Hai Nguyen, Chao Zhang, Günther Knör, Noam Agmon, Paolo Carloni, Peter Pohl |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
Scientific Reports, Vol 7, Iss 1, Pp 1-8 (2017) |
| Druh dokumentu: |
article |
| ISSN: |
2045-2322 |
| DOI: |
10.1038/s41598-017-04675-9 |
| Popis: |
Abstract Proton diffusion along biological membranes is vitally important for cellular energetics. Here we extended previous time-resolved fluorescence measurements to study the time and temperature dependence of surface proton transport. We determined the Gibbs activation energy barrier ΔG ‡ r that opposes proton surface-to-bulk release from Arrhenius plots of (i) protons’ surface diffusion constant and (ii) the rate coefficient for proton surface-to-bulk release. The large size of ΔG ‡ r disproves that quasi-equilibrium exists in our experiments between protons in the near-membrane layers and in the aqueous bulk. Instead, non-equilibrium kinetics describes the proton travel between the site of its photo-release and its arrival at a distant membrane patch at different temperatures. ΔG ‡ r contains only a minor enthalpic contribution that roughly corresponds to the breakage of a single hydrogen bond. Thus, our experiments reveal an entropic trap that ensures channeling of highly mobile protons along the membrane interface in the absence of potent acceptors. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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