Encyclopedia of Metalloproteins

2013 Edition
| Editors: Robert H. Kretsinger, Vladimir N. Uversky, Eugene A. Permyakov

Sodium as Primary and Secondary Coupling Ion in Bacterial Energetics

Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-1533-6_240



Primary coupling ion – ion whose transmembrane electrochemical gradient could directly be generated at the expense of the external energy source and used to perform chemical (ATP synthesis), osmotic (active transport), or mechanical (motility) work. Secondary coupling ion – can be actively transported across the membrane only at the expense of the transmembrane electrochemical gradient of the primary coupling ion.


Perhaps the most prominent biological role of sodium-binding/transporting proteins is their involvement into the transformation of energy in biomembranes. All mitochondria and chloroplasts, as well as most bacteria on our planet, transform a plethora of available external energy sources into the transmembrane electrochemical gradient of H+ ions (proton-motive force, or PMF). The PMFcould be directly used to drive a variety of endergonic processes, such...

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  1. Caplan DA, Subbotina JO, Noskov SY (2008) Molecular mechanism of ion-ion and ion-substrate coupling in the Na+-dependent leucine transporter LeuT. Biophys J 95:4613–4621CrossRefPubMedGoogle Scholar
  2. Dimroth P (1997) Primary sodium ion translocating enzymes. Biochim Biophys Acta 1318:11–51CrossRefPubMedGoogle Scholar
  3. Häse CC, Fedorova N, Galperin MY, Dibrov P (2001) Sodium ion cycle in bacterial pathogens: evidence from cross-genome comparisons. Microbiol Mol Biol Rev 65:353–370CrossRefPubMedGoogle Scholar
  4. Krishnamurthy H, Chayne L, Piscitelli CL, Gouaux E (2009) Unlocking the molecular secrets of sodium-coupled transporters. Nature 459:347–355CrossRefPubMedGoogle Scholar
  5. Mulkidjanian AY, Dibrov P, Galperin MY (2008) The past and present of sodium energetics: may the sodium-motive force be with you. Biochim Biophys Acta 1777:985–992CrossRefPubMedGoogle Scholar
  6. Padan E (2008) The enlightening encounter between structure and function in the NhaA Na+/H+ antiporter. Trends Biochem Sci 33:435–443CrossRefPubMedGoogle Scholar
  7. Saier MH Jr (2000) A functional-phylogenetic classification system for transmembrane solute transporters. Microbiol Mol Biol Rev 64:354–411CrossRefPubMedGoogle Scholar
  8. Skulachev VP (1988) Membrane bioenergetics. Springer, BerlinCrossRefGoogle Scholar
  9. Slonczewski JL, Fujisawa M, Dopson M, Krulwich TA (2009) Cytoplasmic pH measurement and homeostasis in bacteria and archaea. Adv Microb Physiol 55:1–80CrossRefPubMedGoogle Scholar
  10. Thormann KM, Paulick A (2010) Tuning the flagellar motor. Microbiology 156:1275–1283CrossRefPubMedGoogle Scholar
  11. von Ballmoos C, Wiedenmann A, Dimroth P (2009) Essentials of ATP synthesis by F1F0 ATP synthases. Annu Rev Biochem 78:649–672CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.Department of MicrobiologyUniversity of ManitobaWinnipegCanada