Gene Symbol: trkA
Description: NAD-binding component of TrK potassium transporter
Alias: ECK3276, JW3251, sapG
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Rhoads D, Waters F, Epstein W. Cation transport in Escherichia coli. VIII. Potassium transport mutants. J Gen Physiol. 1976;67:325-41 pubmed
    ..This system is repressed by growth in high concentrations of K. Two constitutive systems, TrkA and TrkD, have Km's of 1.5 and 0.5 mM and Vmax's of 550 and 40 at 37 and 30 degrees C, respectively...
  2. Stumpe S, Bakker E. Requirement of a large K+-uptake capacity and of extracytoplasmic protease activity for protamine resistance of Escherichia coli. Arch Microbiol. 1997;167:126-36 pubmed
    ..Experiments with a set of strains carrying mutations in the K+-uptake gene trkA showed a reasonably satisfactory correlation between inhibition of net K+ uptake and the lag time for resumption of ..
  3. Parra Lopez C, Baer M, Groisman E. Molecular genetic analysis of a locus required for resistance to antimicrobial peptides in Salmonella typhimurium. EMBO J. 1993;12:4053-62 pubmed
    ..The SapABCDF system constitutes a novel transporter for enteric bacteria and the first one harboring a periplasmic component with a role in virulence...
  4. Bakker E, Mangerich W. The effects of weak acids on potassium uptake by Escherichia coli K-12 inhibition by low cytoplasmic pH. Biochim Biophys Acta. 1983;730:379-86 pubmed
    The activity of the Escherichia coli K+ transport system TrkA was measured as a function of the cytoplasmic pH of the cell...
  5. Bagramyan K, Mnatsakanyan N, Trchounian A. Formate increases the F0F1-ATPase activity in Escherichia coli growing on glucose under anaerobic conditions at slightly alkaline pH. Biochem Biophys Res Commun. 2003;306:361-5 pubmed
    ..The increase in ATPase activity was absent in atp, trkA, and hyf but not in hyc mutants...
  6. Epstein W, Kim B. Potassium transport loci in Escherichia coli K-12. J Bacteriol. 1971;108:639-44 pubmed
    ..The trk loci are widely scattered over the E. coli chromosome; none of them is very near any other trk locus or near the kdp genes. ..
  7. Bagramyan K, Martirosov S. Formation of an ion transport supercomplex in Escherichia coli. An experimental model of direct transduction of energy. FEBS Lett. 1989;246:149-52 pubmed
    ..Within this supercomplex direct transduction of energy is accomplished via oxidation of 2 SH to S-S. ..
  8. Trchunian A, Ogandzhanian E, Mironova G, Martirosov S. [K+-dependent enzyme activity of H+-ATPase in the E. coli membrane]. Biofizika. 1991;36:102-4 pubmed
    ..coli depended on K+ activity. F1F0 include two additional proteins which correspond to the Trk system. The data improve the possibility to form supercomplex (F1F0-Trk) functioning as the H(+)-K(+)-pump. ..
  9. Mazel D, Co c E, Blanchard S, Saurin W, Marli re P. A survey of polypeptide deformylase function throughout the eubacterial lineage. J Mol Biol. 1997;266:939-49 pubmed publisher
    ..Furthermore, the species of origin of each protein appears to be more recognizable than its function, considering only its amino acid composition...

More Information


  1. Epstein W, Buurman E, McLaggan D, Naprstek J. Multiple mechanisms, roles and controls of K+ transport in Escherichia coli. Biochem Soc Trans. 1993;21:1006-10 pubmed
  2. Meek D, Hayward R. Nucleotide sequence of the rpoA-rplQ DNA of Escherichia coli: a second regulatory binding site for protein S4?. Nucleic Acids Res. 1984;12:5813-21 pubmed
    ..The rpoA-rplQ intercistronic region shows strong primary, and potential secondary structural homologies with the S4-binding sites on 16S rRNA and S13 mRNA. We suggest that S4 represses L17 translation directly. ..
  3. Harms C, Domoto Y, Celik C, Rahe E, Stumpe S, Schmid R, et al. Identification of the ABC protein SapD as the subunit that confers ATP dependence to the K+-uptake systems Trk(H) and Trk(G) from Escherichia coli K-12. Microbiology. 2001;147:2991-3003 pubmed
    ..coli ATP dependence of Trk activity can be independent of Sap proteins. These data are interpreted to mean that Trk systems can interact with an ABC protein other than SapD...
  4. Trchunian A, Vasilian A. [ATPase activity and K+ transport in membranes of anaerobically grown trk-mutants of Escherichia coli]. Biokhimiia. 1993;58:1062-70 pubmed
    ..of Rb+ concentration (but not that of Na+, CL- or NO3-) and only in the wild precursor strain and trkG (but not in trkA, trkE, or trkH mutants)...
  5. Rhoads D, Epstein W. Cation transport in Escherichia coli. IX. Regulation of K transport. J Gen Physiol. 1978;72:283-95 pubmed
    ..and of net K uptake after osmotic upshock are reported for the four K transport systems of Escherichia coli: Kdp, TrkA, TrkD, and TrkF. Energy requirements for K exchange are reported for the Kdp and TrkA systems...
  6. Trchounian A, Kobayashi H. Kup is the major K+ uptake system in Escherichia coli upon hyper-osmotic stress at a low pH. FEBS Lett. 1999;447:144-8 pubmed
    ..10 micromol K+/min/mg protein. Such a K+ uptake was investigated using a mutant defective in Kdp and TrkA but with a functional Kup and a mutant defective in Kdp and Kup but having an active TrkA...
  7. Meinnel T, Blanquet S. Characterization of the Thermus thermophilus locus encoding peptide deformylase and methionyl-tRNA(fMet) formyltransferase. J Bacteriol. 1994;176:7387-90 pubmed
    ..coli. Further sequence analysis of the region surrounding the E. coli fms-fmt locus indicates that the genes bordering the fms-fmt region are not conserved in T. thermophilus. ..
  8. Trchounian A, Kobayashi H. K+ uptake by fermenting Escherichia coli cells: pH dependent mode of the TrkA system operating. Biosci Rep. 2000;20:277-88 pubmed
    Escherichia coli accumulates K+ by means of multiple transport systems, of which TrkA is the most prominent at neutral and alkaline pH while Kup is major at acidic pH...
  9. Trchunian A, Durgar ian S, Ogandzhanian E, Ter Nikogosian V, Vardanian A. [The capacity of anaerobically grown bacteria to exchange the 2H+ of the cell for the K+ of the medium and to maintain a high K+ distribution between cell and medium]. Nauchnye Doki Vyss Shkoly Biol Nauki. 1986;:82-8 pubmed
  10. Dosch D, Helmer G, Sutton S, Salvacion F, Epstein W. Genetic analysis of potassium transport loci in Escherichia coli: evidence for three constitutive systems mediating uptake potassium. J Bacteriol. 1991;173:687-96 pubmed
    ..suggests that high rates of transport, previously considered to represent the activity of a single system, named TrkA, appear to be the sum of two systems, here named TrkG and TrkH...
  11. Buurman E, McLaggan D, Naprstek J, Epstein W. Multiple paths for nonphysiological transport of K+ in Escherichia coli. J Bacteriol. 2004;186:4238-45 pubmed
    ..These results support the view that TrkF is composed of multiple, "aberrant" K+ transport activities, i.e., paths that, regardless of their physiological function, allow K+ to cross the cell membrane by a uniport process. ..
  12. Bossemeyer D, Borchard A, Dosch D, Helmer G, Epstein W, Booth I, et al. K+-transport protein TrkA of Escherichia coli is a peripheral membrane protein that requires other trk gene products for attachment to the cytoplasmic membrane. J Biol Chem. 1989;264:16403-10 pubmed
    The TrkA protein, which is essential for the activity of the constitutive Trk K+-uptake system of Escherichia coli, is a peripheral membrane protein...
  13. Lee C, Cho S, Yoon M, Peterkofsky A, Seok Y. Escherichia coli enzyme IIANtr regulates the K+ transporter TrkA. Proc Natl Acad Sci U S A. 2007;104:4124-9 pubmed
    ..the nitrogen-metabolic phosphotransferase system interacts with and regulates the Escherichia coli K(+) transporter TrkA. Previously we reported that an E...
  14. Kirakosyan G, Bagramyan K, Trchounian A. Redox sensing by Escherichia coli: effects of dithiothreitol, a redox reagent reducing disulphides, on bacterial growth. Biochem Biophys Res Commun. 2004;325:803-6 pubmed
  15. Durand A, Sinha A, Dard Dascot C, Michel B. Mutations Affecting Potassium Import Restore the Viability of the Escherichia coli DNA Polymerase III holD Mutant. PLoS Genet. 2016;12:e1006114 pubmed publisher
    ..Here we describe the isolation and characterization of two suppressor mutations in the trkA and trkE genes, involved in the main E. coli potassium import system...
  16. Trchounian A. Ion exchange in facultative anaerobes: does a proton-potassium pump exist in anaerobic Escherichia Coli?. Anaerobe. 1997;3:355-71 pubmed
  17. Parra Lopez C, Lin R, Aspedon A, Groisman E. A Salmonella protein that is required for resistance to antimicrobial peptides and transport of potassium. EMBO J. 1994;13:3964-72 pubmed
    ..We conducted a molecular genetic analysis of the sapG locus and showed that it encodes a product that is 99% identical to the NAD+ binding protein TrkA, a component of a ..
  18. Meury J, Kepes A. The regulation of potassium fluxes for the adjustment and maintenance of potassium levels in Escherichia coli. Eur J Biochem. 1981;119:165-70 pubmed
    ..It appears that the trkA system, which is the only functional system under these experimental conditions is not a 'pump and leak' type of ..
  19. Meury J, Lebail S, Kepes A. Opening of potassium channels in Escherichia coli membranes by thiol reagents and recovery of potassium tightness. Eur J Biochem. 1980;113:33-8 pubmed
    ..a derepressed kdp uptake system working in the micromolar range of the K+ concentration is responsible for the intracellular pool of K+ and when, in a medium millimolar K+ concentration range, the trkA and trkD systems are predominant.
  20. Hamann A, Bossemeyer D, Bakker E. Physical mapping of the K+ transport trkA gene of Escherichia coli and overproduction of the TrkA protein. J Bacteriol. 1987;169:3138-45 pubmed
    The position on the Escherichia coli chromosome of trkA, a gene coding for a membrane protein involved in K+ transport by the constitutive uptake system Trk, was determined...
  21. Groisman E, Parra Lopez C, Salcedo M, Lipps C, Heffron F. Resistance to host antimicrobial peptides is necessary for Salmonella virulence. Proc Natl Acad Sci U S A. 1992;89:11939-43 pubmed
    ..Our data indicate that the ability to resist the killing effect of host antimicrobial peptides is a virulence property and that several resistance mechanisms operate in S. typhimurium. ..
  22. Trchounian A, Bagramyan K, Poladian A. Formate hydrogenlyase is needed for proton-potassium exchange through the F0F1-ATPase and the TrkA system in anaerobically grown and glycolysing Escherichia coli. Curr Microbiol. 1997;35:201-6 pubmed
    ..H2 production was observed in the trkA trkD kdpA mutant...
  23. Trchounian A, Bagramyan K, Vassilian A, Poladian A. Relationship between formate hydrogen lyase and proton-potassium pump under heterolactic fermentation in Escherichia coli: functional multienzyme associations in the cell membrane. Membr Cell Biol. 2000;13:511-26 pubmed
    ..This mutant acidified the medium and uptook K+ with Km typical for TrkA, but the stoichiometry of the DCC-inhibited fluxes was variable, and the K+ gradient between the cytoplasm and the ..
  24. Trchounian A, Vassilian A. Relationship between the F0F1-ATPase and the K(+)-transport system within the membrane of anaerobically grown Escherichia coli. N,N'-dicyclohexylcarbodiimide-sensitive ATPase activity in mutants with defects in K(+)-transport. J Bioenerg Biomembr. 1994;26:563-71 pubmed
    ..This effect was observed only in parent and in the trkG, but not in the trkA, trkE, or trkH mutants...
  25. Rhoads D, Epstein W. Energy coupling to net K+ transport in Escherichia coli K-12. J Biol Chem. 1977;252:1394-401 pubmed
    ..the Kdp system, a repressible high affinity (Km=2 muM) system probably coded for by four linked Kdp genes; (b) the Trka system, a constitutive system with high rate and modest affinity (Km=1...
  26. Trchounian A, Ohanjayan E, Zakharyan E. Regulation of intracellular pH and proton-potassium exchange in fermenting Escherichia coli grown anaerobically in alkaline medium. Membr Cell Biol. 1998;12:67-78 pubmed
    ..coli mutants with the defect in the alpha-subunit of H(+)-ATPase F0F1 complex (uncA) or in the TrkA system of K+ uptake (trkA trkD)...
  27. Schlosser A, Hamann A, Bossemeyer D, Schneider E, Bakker E. NAD+ binding to the Escherichia coli K(+)-uptake protein TrkA and sequence similarity between TrkA and domains of a family of dehydrogenases suggest a role for NAD+ in bacterial transport. Mol Microbiol. 1993;9:533-43 pubmed
    The nucleotide sequence of trkA, a gene encoding a surface component of the constitutive K(+)-uptake systems TrkG and TrkH from Escherichia coli, was determined...
  28. Stewart L, Bakker E, Booth I. Energy coupling to K+ uptake via the Trk system in Escherichia coli: the role of ATP. J Gen Microbiol. 1985;131:77-85 pubmed
    ..Using inhibitors and unc mutants we show that Trk is not an ATPase but may be regulated by ATP. Possible mechanisms of energy coupling to Trk are discussed. ..
  29. Trchunian A, Ogandzhanian E, Martirosov S. [N,N'-dicyclohexylcarbodiimide-sensitive K+-dependent ATPase activity in Escherichia coli]. Nauchnye Doki Vyss Shkoly Biol Nauki. 1989;:90-5 pubmed
  30. Guo Y, Xue Y, Liu J, Wang Q, Ma Y. Characterization and function analysis of a Halo-alkaline-adaptable Trk K+ uptake system in Alkalimonas amylolytica strain N10. Sci China C Life Sci. 2009;52:949-57 pubmed publisher
    ..These two genes, Aa-trkA (1337 bp) and Aa-trkH (1452 bp), were adjacent on the A...
  31. Stumpe -, Bakker -. Requirement of a large K+-uptake capacity and of extracytoplasmic protease activity for protamine resistance of Escherichia coli. Arch Microbiol. 1997;167:126-36 pubmed
    ..Experiments with a set of strains carrying mutations in the K+-uptake gene trkA showed a reasonably satisfactory correlation between inhibition of net K+ uptake and the lag time for resumption of ..