Gene Symbol: proX
Description: glycine betaine/proline ABC transporter periplasmic binding protein; cold shock protein
Alias: ECK2673, JW2654, osrA, proU
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Laurent Winter C, Ngo S, Danchin A, Bertin P. Role of Escherichia coli histone-like nucleoid-structuring protein in bacterial metabolism and stress response--identification of targets by two-dimensional electrophoresis. Eur J Biochem. 1997;244:767-73 pubmed
    ..Finally, synthesis of several proteins belonging to the heat-shock regulon, more particularly molecular chaperones, was induced in an hns mutant. ..
  2. Verheul A, Wouters J, Rombouts F, Abee T. A possible role of ProP, ProU and CaiT in osmoprotection of Escherichia coli by carnitine. J Appl Microbiol. 1998;85:1036-46 pubmed
    ..that, under osmotic stress, carnitine accumulates in the cytoplasm following import through the ProP and ProU transport systems. Betaine and carnitine also protect E...
  3. Polissi A, De Laurentis W, Zangrossi S, Briani F, Longhi V, Pesole G, et al. Changes in Escherichia coli transcriptome during acclimatization at low temperature. Res Microbiol. 2003;154:573-80 pubmed
    ..Interestingly, we found that PNPase both negatively and positively modulated the transcript abundance of some of these genes, thus suggesting a complex role of PNPase in controlling cold adaptation. ..
  4. Gul N, Poolman B. Functional reconstitution and osmoregulatory properties of the ProU ABC transporter from Escherichia coli. Mol Membr Biol. 2013;30:138-48 pubmed publisher
    The ATP-binding cassette (ABC) transporter ProU from Escherichia coli translocates a wide range of compatible solutes and contributes to the regulation of cell volume, which is particularly important when the osmolality of the environment ..
  5. Stirling D, Hulton C, Waddell L, Park S, Stewart G, Booth I, et al. Molecular characterization of the proU loci of Salmonella typhimurium and Escherichia coli encoding osmoregulated glycine betaine transport systems. Mol Microbiol. 1989;3:1025-38 pubmed
    The proU loci of Salmonella typhimurium and Escherichia coli encode high-affinity glycine betaine transport systems which play an important role in survival under osmotic stress...
  6. Prince W, Villarejo M. Osmotic control of proU transcription is mediated through direct action of potassium glutamate on the transcription complex. J Biol Chem. 1990;265:17673-9 pubmed
    Osmoregulated transcription from the proU promoter of Escherichia coli has been successfully reconstituted from purified components in a simple in vitro system consisting of plasmid DNA template, RNA polymerase, and nucleotides in the ..
  7. Sutherland L, Cairney J, Elmore M, Booth I, Higgins C. Osmotic regulation of transcription: induction of the proU betaine transport gene is dependent on accumulation of intracellular potassium. J Bacteriol. 1986;168:805-14 pubmed
    The proU locus, which encodes a high-affinity betaine transport system, and the kdp operon, which encodes a potassium transport system, are the principal osmoresponsive genes in Escherichia coli and Salmonella typhimurium...
  8. Gowrishankar J, Jayashree P, Rajkumari K. Molecular cloning of an osmoregulatory locus in Escherichia coli: increased proU gene dosage results in enhanced osmotolerance. J Bacteriol. 1986;168:1197-204 pubmed
    The proU locus in Escherichia coli encodes an important osmoregulatory function which mediates the growth-promoting effect of L-proline and glycine betaine in high-osmolarity media...
  9. Weber A, Kögl S, Jung K. Time-dependent proteome alterations under osmotic stress during aerobic and anaerobic growth in Escherichia coli. J Bacteriol. 2006;188:7165-75 pubmed
    ..The protein profiles revealed an induction of 12 proteins (Dps, HchA, HdhA, InfB, OsmC, OsmY, ProX, KatE, PspA, TalA, TktB, and TreF) under osmotic stress in an aerobic milieu...

More Information


  1. Kirkpatrick C, Maurer L, Oyelakin N, Yoncheva Y, Maurer R, Slonczewski J. Acetate and formate stress: opposite responses in the proteome of Escherichia coli. J Bacteriol. 2001;183:6466-77 pubmed
    ..levels of 37 proteins, including periplasmic transporters for amino acids and peptides (ArtI, FliY, OppA, and ProX), metabolic enzymes (YfiD and GatY), the RpoS growth phase regulon, and the autoinducer synthesis protein LuxS...
  2. Barron A, Jung J, Villarejo M. Purification and characterization of a glycine betaine binding protein from Escherichia coli. J Biol Chem. 1987;262:11841-6 pubmed
    ..The protein was absent in mutants with lambda placMu insertions in the proU region, a locus involved in transport of the osmoprotectant glycine betaine...
  3. Gowrishankar J. Identification of osmoresponsive genes in Escherichia coli: evidence for participation of potassium and proline transport systems in osmoregulation. J Bacteriol. 1985;164:434-45 pubmed
    ..obtained to support the notion that osrA codes for an osmoresponsive L-proline transport system and is homologus to proU in Salmonella typhimurium...
  4. May G, Faatz E, Villarejo M, Bremer E. Binding protein dependent transport of glycine betaine and its osmotic regulation in Escherichia coli K12. Mol Gen Genet. 1986;205:225-33 pubmed
    ..of a high-affinity, binding protein dependent transport system for glycine betaine, which is encoded by the proU region...
  5. Faatz E, Middendorf A, Bremer E. Cloned structural genes for the osmotically regulated binding-protein-dependent glycine betaine transport system (ProU) of Escherichia coli K-12. Mol Microbiol. 1988;2:265-79 pubmed
    The proU locus of Escherichia coli encodes a high-affinity, binding-protein-dependent transport system (ProU) for the osmoprotectant glycine betaine...
  6. Grothe S, Krogsrud R, McClellan D, Milner J, Wood J. Proline transport and osmotic stress response in Escherichia coli K-12. J Bacteriol. 1986;166:253-9 pubmed
    ..Mutation proU205, which was similar in genetic map location and phenotype to other proU mutations isolated in E...
  7. Schiefner A, Breed J, B sser L, Kneip S, Gade J, Holtmann G, et al. Cation-pi interactions as determinants for binding of the compatible solutes glycine betaine and proline betaine by the periplasmic ligand-binding protein ProX from Escherichia coli. J Biol Chem. 2004;279:5588-96 pubmed publisher
    ..the periplasmic ligand-binding protein ProX from the Escherichia coli ATP-binding cassette transport system ProU binds the compatible solutes glycine betaine and proline betaine with high affinity and specificity...
  8. Dattananda C, Gowrishankar J. Osmoregulation in Escherichia coli: complementation analysis and gene-protein relationships in the proU locus. J Bacteriol. 1989;171:1915-22 pubmed
    ..The data indicate that proU is an operon with three genes, designated in order proV, proW, and proX, encoding respectively the gene products above...
  9. Lucht J, Bremer E. Adaptation of Escherichia coli to high osmolarity environments: osmoregulation of the high-affinity glycine betaine transport system proU. FEMS Microbiol Rev. 1994;14:3-20 pubmed
    ..In this overview, we discuss the properties of the high-affinity glycine betaine transport system ProU and the osmotic regulation of its structural genes.
  10. Sigdel T, Cilliers R, Gursahaney P, Thompson P, Easton J, Crowder M. Probing the adaptive response of Escherichia coli to extracellular Zn(II). Biometals. 2006;19:461-71 pubmed
    ..coli proteins, and the results are discussed in light of recent genomic profiling studies on the adaptive response of E. coli cells to stress by Zn(II) excess. ..
  11. Gowrishankar J. Nucleotide sequence of the osmoregulatory proU operon of Escherichia coli. J Bacteriol. 1989;171:1923-31 pubmed
    The sequence of 4,362 nucleotides encompassing the proU operon of Escherichia coli was determined...