Purification and properties of the Escherichia coli nucleoside transporter NupG, a paradigm for a major facilitator transporter sub-family

Hao Xie, Simon G. Patching, Maurice P. Gallagher, Gary Litherland, Adrian R. Brough, Henrietta Venter, Sylvia Y.M. Yao, Amy M.L. Ng, James D. Young, Richard B. Herbert, Peter J.F. Henderson, Stephen A. Baldwin

Research output: Contribution to journalArticle

33 Citations (Scopus)


NupG from Escherichia coli is the archetype of a family of nucleoside transporters found in several eubacterial groups and has distant homologues in eukaryotes, including man. To facilitate investigation of its molecular mechanism, we developed methods for expressing an oligohistidine-tagged form of NupG both at high levels (>20% of the inner membrane protein) in E. coli and in Xenopus laevis oocytes. In E. coli recombinant NupG transported purine (adenosine) and pyrimidine (uridine) nucleosides with apparent Km values of ∼20–30 μM and transport was energized primarily by the membrane potential component of the proton motive force. Competition experiments in E. coli and measurements of uptake in oocytes confirmed that NupG was a broad-specificity transporter of purine and pyrimidine nucleosides. Importantly, using high-level expression in E. coli and magic-angle spinning cross-polarization solid-state nuclear magnetic resonance, we have for the first time been able directly to measure the binding of the permeant ([1′-13C]uridine) to the protein and to assess its relative mobility within the binding site, under non-energized conditions. Purification of over-expressed NupG to near homogeneity by metal chelate affinity chromatography, with retention of transport function in reconstitution assays, was also achieved. Fourier transform infrared and circular dichroism spectroscopy provided further evidence that the purified protein retained its 3D conformation and was predominantly α-helical in nature, consistent with a proposed structure containing 12 transmembrane helices. These findings open the way to elucidating the molecular mechanism of transport in this key family of membrane transporters.
Original languageEnglish
Pages (from-to)323-336
Number of pages14
JournalMolecular Membrane Biology
Issue number5
Publication statusPublished - 2004
Externally publishedYes


  • bacteria
  • solid-state NMR
  • major facilitator superfamily
  • transport
  • Nucleoside

Fingerprint Dive into the research topics of 'Purification and properties of the Escherichia coli nucleoside transporter NupG, a paradigm for a major facilitator transporter sub-family'. Together they form a unique fingerprint.

  • Research Output

    • 33 Citations
    • 4 Article

    Expression and modulation of TUB by insulin and thyroid hormone in primary rat and murine 3T3-L1 adipocytes

    Stretton, C., Litherland, G. J., Moynihan, A., Hajduch, E. & Hundal, H. S., 25 Dec 2009, In : Biochemical and Biophysical Research Communications. 390, 4, p. 1328-1333

    Research output: Contribution to journalArticle

    6 Citations (Scopus)

    Fructose transport and metabolism in adipose tissue of Zucker rats: diminished GLUT5 activity during obesity and insulin resistance

    Litherland, G. J., Hajduch, E., Gould, G. W. & Hundal, H. S., 2004, In : Molecular and Cellular Biochemistry. 261, 1, p. 23-33 11 p.

    Research output: Contribution to journalArticle

  • 36 Citations (Scopus)

    Insulin regulates the expression of the GLUT5 transporter in L6 skeletal muscle cells

    Hajduch, E., Litherland, G., Turban, S., Brot-Laroche, E. & Hundal, H. S., 14 Aug 2003, In : FEBS Letters. 549, 1-3, p. 77-82 6 p.

    Research output: Contribution to journalArticle

    Open Access
  • 12 Citations (Scopus)

    Cite this

    Xie, H., Patching, S. G., Gallagher, M. P., Litherland, G., Brough, A. R., Venter, H., Yao, S. Y. M., Ng, A. M. L., Young, J. D., Herbert, R. B., Henderson, P. J. F., & Baldwin, S. A. (2004). Purification and properties of the Escherichia coli nucleoside transporter NupG, a paradigm for a major facilitator transporter sub-family. Molecular Membrane Biology, 21(5), 323-336. https://doi.org/10.1080/09687860400003941