Aerobic respiratory chain of Escherichia coli is not allowed to work in fully uncoupled mode.
Proc Natl Acad Sci U S A
; 108(42): 17320-4, 2011 Oct 18.
Article
in En
| MEDLINE
| ID: mdl-21987791
ABSTRACT
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Electron Transport
/
Escherichia coli
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
2011
Document type:
Article
Affiliation country:
RUSSIA