TY  - JOUR
AU  - Weichselbaum, Ewald
AU  - Österbauer, Maria
AU  - Knyazev, Denis G.
AU  - Batishchev, Oleg V.
AU  - Akimov, Sergey A.
AU  - Hai Nguyen, Trung
AU  - Zhang, Chao
AU  - Knör, Günther
AU  - Agmon, Noam
AU  - Carloni, Paolo
AU  - Pohl, Peter
TI  - Origin of proton affinity to membrane/water interfaces
JO  - Scientific reports
VL  - 7
IS  - 1
SN  - 2045-2322
CY  - London
PB  - Nature Publishing Group
M1  - FZJ-2017-04534
SP  - 4553
PY  - 2017
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000404618400067
DO  - DOI:10.1038/s41598-017-04675-9
UR  - https://juser.fz-juelich.de/record/834626
ER  -