Aerobic respiratory chain of Escherichia coli is not allowed to work in fully uncoupled mode
| Autor: | Michael I. Verkhovsky, Dmitry A. Bloch, Marina Verkhovskaya, Ranjani Murali, Huazhi Han, Vitaliy B. Borisov, Robert B. Gennis |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Cytochrome
Ubiquinol oxidase Respiratory chain Models Biological Membrane Potentials Electron Transport Adenosine Triphosphate Cytochrome C1 Escherichia coli Multidisciplinary biology ATP synthase Chemistry Chemiosmosis Escherichia coli Proteins Proton-Motive Force Biological Sciences Cytochrome b Group NAD Electron transport chain Aerobiosis Biochemistry Electron Transport Chain Complex Proteins Coenzyme Q – cytochrome c reductase biology.protein Cytochromes Oxidoreductases |
| Popis: | Escherichia coli is known to couple aerobic respiratory catabolism to ATP synthesis by virtue of the primary generators of the proton motive force—NADH dehydrogenase I, cytochrome bo 3 , and cytochrome bd -I. An E. coli mutant deficient in NADH dehydrogenase I, bo 3 and bd -I can, nevertheless, grow aerobically on nonfermentable substrates, although its sole terminal oxidase cytochrome bd -II has been reported to be nonelectrogenic. In the current work, the ability of cytochrome bd -II to generate a proton motive force is reexamined. Absorption and fluorescence spectroscopy and oxygen pulse methods show that in the steady-state, cytochrome bd -II does generate a proton motive force with a H + /e - ratio of 0.94 ± 0.18. This proton motive force is sufficient to drive ATP synthesis and transport of nutrients. Microsecond time-resolved, single-turnover electrometry shows that the molecular mechanism of generating the proton motive force is identical to that in cytochrome bd -I. The ability to induce cytochrome bd -II biosynthesis allows E. coli to remain energetically competent under a variety of environmental conditions. |
| Databáze: | OpenAIRE |
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