期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 108, 期 42, 页码 17320-17324出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1108217108
关键词
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资金
- Russian Foundation for Basic Research [11-04-00031-a]
- National Institutes of Health [HL16101]
- Biocentrum Helsinki, Sigrid Juselius Foundation
- Magnus Ehrnrooth Foundation
- Academy of Finland
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, bo3 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.
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