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Electrogenic proton translocation by the chloroplast cytochrome b 6 / f complex reconstituted into phospholipid vesicles
Author(s) -
Hurt Eduard C.,
Hauska Günter,
Shahak Yosepha
Publication year - 1982
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(82)81103-4
Subject(s) - vesicle , valinomycin , cytochrome , chemistry , plastocyanin , biophysics , phospholipid , cytochrome c , uncoupling agents , chloroplast , cytochrome f , proton transport , liposome , proton , mitochondrion , membrane , biochemistry , biology , thylakoid , enzyme , physics , photosystem i , quantum mechanics , gene
When the cytochrome b 6 / f complex from chloroplasts is incorporated into liposomes, reduction of external plastocyanin by plastoquinol is stimulated under uncoupling conditions. An extra H + /e − is ejected from the vesicles during the reaction, in addition to the scalar proton liberated from plastoquinol. This is stimulated by valinomycin/K + and abolished under uncoupling conditions. Furthermore, the formation of a membrane potential during the reaction, negative inside the vesicles, is observed with the help of carbocyanine dyes. We conclude that the cytochrome b 6 / f complex, like the cytochrome bc 1 from mitochondria, functions as an electrogenic proton translocator.