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Protonmotive force generation by a redox loop mechanism
Author(s) -
Jormakka Mika,
Byrne Bernadette,
Iwata So
Publication year - 2003
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/s0014-5793(03)00389-2
Subject(s) - redox , chemiosmosis , chemistry , formate dehydrogenase , biophysics , formate , respiratory chain , inner membrane , atp synthase , mitochondrion , dehydrogenase , half reaction , biochemistry , enzyme , biology , inorganic chemistry , catalysis
Respiration involves the oxidation and reduction of substrate for the redox‐linked formation of a protonmotive force (PMF) across the inner membrane of mitochondria or the plasma membrane of bacteria. A mechanism for PMF generation was first suggested by Mitchell in his chemiosmotic theory. In the original formulations of the theory, Mitchell envisaged that proton translocation was driven by a ‘redox loop’ between two catalytically distinct enzyme complexes. Experimental data have shown that this redox loop does not operate in mitochondria, but has been confirmed as an important mechanism in bacteria. The nitrate respiratory pathway in Escherichia coli is a paradigm for a protonmotive redox loop. The structure of one of the enzymes in this two‐component system, formate dehydrogenase‐N, has revealed the structural basis for the PMF generation by the redox loop mechanism and this forms the basis of this review.