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Energetics of tetracycline efflux system encoded by Tn10 in Escherichia coli
Author(s) -
Kaneko Midori,
Yamaguchi Akihito,
Sawai Tetsuo
Publication year - 1985
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 - 10.1016/0014-5793(85)80149-6
Subject(s) - nigericin , valinomycin , tetracycline , ionophore , antiporter , escherichia coli , chemistry , tn10 , biophysics , vesicle , membrane transport , biochemistry , chemiosmosis , efflux , membrane potential , membrane , enterobacteriaceae , biology , antibiotics , enzyme , atp synthase , gene
Tritiated tetracycline was actively accumulated in inverted membrane vesicles prepared from Escherichia coli W3104 rif , which has a transposon, Tn10, on the plasmid, R388, by means of a protonmotive force when NADH was added as an energy source. The tetracycline accumulation was reduced to about one‐half the full value on the addition of a cation/proton‐exchange ionophore, nigericin. In contrast, remarkable stimulation of the tetracycline accumulation was observed with a K + ‐specific ionophore, valinomycin. The accumulation of [ 3 H]tetracycline could also be driven by an artificially imposed interior‐acidic pH gradient (ΔpH), but not, however, by an artificially imposed interior‐positive membrane potential (Δψ). These results strongly indicate that the plasmid‐encoded tetracycline transport was mainly due to an electrically neutral proton/tetracycline antiport system.