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The efficiency of energized protons for ATP synthesis depends on the membrane topography in thylakoids
Author(s) -
Haraux Francis,
Sigalat Claude,
Moreau Annie,
de Kouchkovsky Yaroslav
Publication year - 1983
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)80614-5
Subject(s) - thylakoid , proton , electrochemical gradient , coupling (piping) , chemistry , biophysics , membrane , chemiosmosis , chain (unit) , chloroplast , physics , materials science , atp synthase , biochemistry , biology , nuclear physics , astronomy , metallurgy , gene , enzyme
In thylakoids system II water‐splitting proton generation is mainly localized in grana stacks, whereas system I plastoquinol reoxidation, is essentially restricted to non‐appressed regions, such as stromal lamellae; the same is true for the coupling factor. For a given mean proton gradient, a system II chain was found to be less able to drive phosphorylation than a system I or a system I + II chain. These results support our microchemiosmotic hypothesis, based on the existence of lateral resistances to H + movements. They confirm that the proton gradients at the redox chain and at the coupling factor are unequal and that both are different from their mean experimentally measured value.