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Channel character of uncoupling protein‐mediated transport
Author(s) -
Ježek Petr,
Jabůrek Martin,
Garlid Keith D.
Publication year - 2010
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2010.02.068
Subject(s) - protonation , bilayer , chemistry , biophysics , function (biology) , inner mitochondrial membrane , flux (metallurgy) , membrane potential , ion , mitochondrion , biochemistry , biology , membrane , microbiology and biotechnology , organic chemistry
Mitochondrial uncoupling proteins (UCPs) are pure anion uniporters, which mediate fatty acid (FA) uniport leading to FA cycling. Protonated FAs then flip‐flop back across the lipid bilayer. An existence of pure proton channel in UCPs is excluded by the equivalent flux‐voltage dependencies for uniport of FAs and halide anions, which are best described by the Eyring barrier variant with a single energy well in the middle of two peaks. Experiments with FAs unable to flip and alkylsulfonates also support this view. Phylogenetically, UCPs took advantage of the common FA‐uncoupling function of SLC25 family carriers and dropped their solute transport function.