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 i

SUBMITTER: Mulkidjanian AY 

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

REPOSITORIES: biostudies-literature