Department of Cell Biochemistry, Netherlands Cancer Institute, 1066 OX Amsterdam, The Nether-lands.
Nark is a nitrite-extrusion system involved in anaerobic nitrate respiration by Escherichia coli
Article first published online: 27 OCT 2006
Volume 12, Issue 4, pages 579–586, May 1994
How to Cite
Rowe, J. J., Ubbink-Kok, T., Molenaar, D., Konings, W. N. and Driessen, A. J. M. (1994), Nark is a nitrite-extrusion system involved in anaerobic nitrate respiration by Escherichia coli. Molecular Microbiology, 12: 579–586. doi: 10.1111/j.1365-2958.1994.tb01044.x
- Issue published online: 27 OCT 2006
- Article first published online: 27 OCT 2006
- Received 3 December, 1993; revised 18 February, 1994; accepted 21 February 1994.
Escherichia coli can use nitrate as a terminal electron acceptor for anaerobic respiration. A polytopic membrane protein, termed NarK, has been implicated in nitrate uptake and nitrite excretion and is thought to function as a nitrate/nitrite antiporter. The longest-lived radioactive isotope of nitrogen, 13N-nitrate (half-life = 9.96 min) and the nitrite-sensitive fluorophore N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide have now been used to define the function of NarK. At low concentrations of nitrate, NarK mediates the electrogenic excretion of nitrite rather than nitrate/nitrite exchange. This process prevents intracellular accumulation of toxic levels of nitrite and allows further detoxification in the periplasm through the action of nitrite reductase.