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A single mutation converts bacterial Na + ‐transporting rhodopsin into an H + transporter
Author(s) -
Mamedov Mahir D.,
Mamedov Adalyat M.,
Bertsova Yulia V.,
Bogachev Alexander V.
Publication year - 2016
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 - 10.1002/1873-3468.12324
Subject(s) - cytoplasm , rhodopsin , escherichia coli , chemistry , ion transporter , ion , transporter , conductance , biophysics , membrane transport , biochemistry , membrane , biology , physics , gene , retinal , organic chemistry , condensed matter physics
Na + ‐rhodopsins are light‐driven pumps used by marine bacteria to extrude Na + ions from the cytoplasm. We show here that replacement of Gln123 on the cytoplasmic side of the ion‐conductance channel with aspartate or glutamate confers H + transport activity to the Na + ‐rhodopsin from Dokdonia sp. PRO 95. The Q123E variant could transport H + out of Escherichia coli cells in a medium containing 100 m m Na + and SCN − as the penetrating anion. The rates of the photocycle steps of this variant were only marginally dependent on Na + , and the major electrogenic steps were the decays of the K and O intermediates.