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The past and present of sodium energetics: may the sodium-motive force be with you.

ABSTRACT: All living cells routinely expel Na(+) ions, maintaining lower concentration of Na(+) in the cytoplasm than in the surrounding milieu. In the vast majority of bacteria, as well as in mitochondria and chloroplasts, export of Na(+) occurs at the expense of the proton-motive force. Some bacteria, however, possess primary generators of the transmembrane electrochemical gradient of Na(+) (sodium-motive force). These primary Na(+) pumps have been traditionally seen as adaptations to high external pH or to high temperature. Subsequent studies revealed, however, the mechanisms for primary sodium pumping in a variety of non-extremophiles, such as marine bacteria and certain bacterial pathogens. Further, many alkaliphiles and hyperthermophiles were shown to rely on H(+), not Na(+), as the coupling ion. We review here the recent progress in understanding the role of sodium-motive force, including (i) the conclusion on evolutionary primacy of the sodium-motive force as energy intermediate, (ii) the mechanisms, evolutionary advantages and limitations of switching from Na(+) to H(+) as the coupling ion, and (iii) the possible reasons why certain pathogenic bacteria still rely on the sodium-motive force.

SUBMITTER: Mulkidjanian AY

PROVIDER: S-EPMC2695506 | biostudies-literature | 2008 Jul-Aug

REPOSITORIES: biostudies-literature

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The past and present of sodium energetics: may the sodium-motive force be with you.

Mulkidjanian Armen Y AY Dibrov Pavel P Galperin Michael Y MY

Biochimica et biophysica acta 20080427 7-8

All living cells routinely expel Na(+) ions, maintaining lower concentration of Na(+) in the cytoplasm than in the surrounding milieu. In the vast majority of bacteria, as well as in mitochondria and chloroplasts, export of Na(+) occurs at the expense of the proton-motive force. Some bacteria, however, possess primary generators of the transmembrane electrochemical gradient of Na(+) (sodium-motive force). These primary Na(+) pumps have been traditionally seen as adaptations to high external pH o ...[more]

PMID: 18485887

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The past and present of sodium energetics: may the sodium-motive force be with you.

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The past and present of sodium energetics: may the sodium-motive force be with you.

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