%0 Journal Article
%A Weichselbaum, Ewald
%A Österbauer, Maria
%A Knyazev, Denis G.
%A Batishchev, Oleg V.
%A Akimov, Sergey A.
%A Hai Nguyen, Trung
%A Zhang, Chao
%A Knör, Günther
%A Agmon, Noam
%A Carloni, Paolo
%A Pohl, Peter
%T Origin of proton affinity to membrane/water interfaces
%J Scientific reports
%V 7
%N 1
%@ 2045-2322
%C London
%I Nature Publishing Group
%M FZJ-2017-04534
%P 4553
%D 2017
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000404618400067
%R 10.1038/s41598-017-04675-9
%U https://juser.fz-juelich.de/record/834626