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. 1992 Aug;174(15):4893–4898. doi: 10.1128/jb.174.15.4893-4898.1992

Mechanism of Na(+)-dependent citrate transport in Klebsiella pneumoniae.

M E van der Rest 1, D Molenaar 1, W N Konings 1
PMCID: PMC206300  PMID: 1629151

Abstract

Citrate transport via CitS of Klebsiella pneumoniae has been shown to depend on the presence of Na+. This transport system has been expressed in Escherichia coli, and uptake of citrate in E. coli membrane vesicles via this uptake system was found to be an electrogenic process, although the pH gradient is the main driving force for citrate uptake (M. E. van der Rest, R. M. Siewe, T. Abee, E. Schwartz, D. Oesterhelt, and W. N. Konings, J. Biol. Chem. 267:8971-8976, 1992). Analysis of the affinity constants for the different citrate species at different pH values of the medium indicates that H-citrate2- is the transported species. Since the electrical potential across the membrane is a driving force for citrate transport, this indicates that transport occurs in symport with at least three monovalent cations. Citrate efflux is stimulated by Na+ concentrations of up to 5 mM but inhibited by higher Na+ concentrations. Citrate exchange, however, is stimulated by all Na+ concentrations, indicating sequential events in which Na+ binds before citrate for translocation followed by a release of Na+ after release of citrate. CitS has, at pH 6.0 and in the presence of 5 mM citrate on both sides of the membrane, an apparent affinity (K(app)) for Na+ of 200 microM. The Na+/citrate stoichiometry was found to be 1. It is postulated that H-citrate2- is transported via CitS in symport with one Na+ and at least two H+ ions.

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Selected References

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  1. Bae-Lee M., Carman G. M. Regulation of yeast phosphatidylserine synthase and phosphatidylinositol synthase activities by phospholipids in Triton X-100/phospholipid mixed micelles. J Biol Chem. 1990 May 5;265(13):7221–7226. [PubMed] [Google Scholar]
  2. Baldwin S. A., Henderson P. J. Homologies between sugar transporters from eukaryotes and prokaryotes. Annu Rev Physiol. 1989;51:459–471. doi: 10.1146/annurev.ph.51.030189.002331. [DOI] [PubMed] [Google Scholar]
  3. Dimroth P. Sodium ion transport decarboxylases and other aspects of sodium ion cycling in bacteria. Microbiol Rev. 1987 Sep;51(3):320–340. doi: 10.1128/mr.51.3.320-340.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Dimroth P., Thomer A. Citrate transport in Klebsiella pneumoniae. Biol Chem Hoppe Seyler. 1986 Aug;367(8):813–823. doi: 10.1515/bchm3.1986.367.2.813. [DOI] [PubMed] [Google Scholar]
  5. Konings W. N., Barnes E. M., Jr, Kaback H. R. Mechanisms of active transport in isolated membrane vesicles. 2. The coupling of reduced phenazine methosulfate to the concentrative uptake of beta-galactosides and amino acids. J Biol Chem. 1971 Oct 10;246(19):5857–5861. [PubMed] [Google Scholar]
  6. Koser S. A. CORRELATION OF CITRATE UTILIZATION BY MEMBERS OF THE COLON-AEROGENES GROUP WITH OTHER DIFFERENTIAL CHARACTERISTICS AND WITH HABITAT. J Bacteriol. 1924 Jan;9(1):59–77. doi: 10.1128/jb.9.1.59-77.1924. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. LARA F. J. S., STOKES J. L. Oxidation of citrate by Escherichia coli. J Bacteriol. 1952 Mar;63(3):415–420. doi: 10.1128/jb.63.3.415-420.1952. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  9. Schwarz E., Oesterhelt D. Cloning and expression of Klebsiella pneumoniae genes coding for citrate transport and fermentation. EMBO J. 1985 Jun;4(6):1599–1603. doi: 10.1002/j.1460-2075.1985.tb03823.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Van der Rest M. E., Abee T., Molenaar D., Konings W. N. Mechanism and energetics of a citrate-transport system of Klebsiella pneumoniae. Eur J Biochem. 1991 Jan 1;195(1):71–77. doi: 10.1111/j.1432-1033.1991.tb15677.x. [DOI] [PubMed] [Google Scholar]
  11. van der Rest M. E., Schwarz E., Oesterhelt D., Konings W. N. DNA sequence of a citrate carrier of Klebsiella pneumoniae. Eur J Biochem. 1990 Apr 30;189(2):401–407. doi: 10.1111/j.1432-1033.1990.tb15502.x. [DOI] [PubMed] [Google Scholar]
  12. van der Rest M. E., Siewe R. M., Abee T., Schwarz E., Oesterhelt D., Konings W. N. Nucleotide sequence and functional properties of a sodium-dependent citrate transport system from Klebsiella pneumoniae. J Biol Chem. 1992 May 5;267(13):8971–8976. [PubMed] [Google Scholar]

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