Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 1995 Aug 1;309(Pt 3):877–882. doi: 10.1042/bj3090877

The hydrophobic mannoside Man alpha 1-6Man alpha 1-S-(CH2)7-CH3 acts as an acceptor for the UDP-Gal:glycosylphosphatidylinositol anchor alpha 1,3-galactosyltransferase of Trypanosoma brucei.

S Pingel 1, R A Field 1, M L Güther 1, M Duszenko 1, M A Ferguson 1
PMCID: PMC1135713  PMID: 7639705

Abstract

The variant surface glycoproteins (VSGs) of Trypanosoma brucei are attached to the plasma membrane via a glycosylphosphatidylinositol (GPI) membrane anchor. This anchor contains the core sequence ethanolamine-PO4-6Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN alpha 1-6myo-inositol, which is conserved in all GPI anchors, and a unique alpha Gal side chain attached to the 3-position of the alpha Man residue adjacent to the alpha GlcN residue. Here we report that trypanosome membranes can catalyse the transfer of Gal from UDP-Gal to the hydrophobic thioglycoside Man alpha 1-6Man alpha 1-S-(CH2)7-CH3. Characterization of the galactosylated products by electrospray mass spectrometry, exoglycosidase digestion and periodate-oxidation studies revealed that the major product was Man alpha 1-6(Gal alpha 1-3)Man alpha 1-S-(CH2)7-CH3. The similarity of this product to part of the mature VSG GPI anchor suggests that the thioglycoside is able to act as an acceptor for the trypanosome-specific UDP-Gal-GPI anchor alpha 1,3-galactosyltransferase.

Full text

PDF
879

Images in this article

879Figure 1
on p.879

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Cross G. A. Cellular and genetic aspects of antigenic variation in trypanosomes. Annu Rev Immunol. 1990;8:83–110. doi: 10.1146/annurev.iy.08.040190.000503. [DOI] [PubMed] [Google Scholar]
  2. Cross G. A. Identification, purification and properties of clone-specific glycoprotein antigens constituting the surface coat of Trypanosoma brucei. Parasitology. 1975 Dec;71(3):393–417. doi: 10.1017/s003118200004717x. [DOI] [PubMed] [Google Scholar]
  3. Ferguson M. A., Homans S. W., Dwek R. A., Rademacher T. W. Glycosyl-phosphatidylinositol moiety that anchors Trypanosoma brucei variant surface glycoprotein to the membrane. Science. 1988 Feb 12;239(4841 Pt 1):753–759. doi: 10.1126/science.3340856. [DOI] [PubMed] [Google Scholar]
  4. Ferguson M. A., Masterson W. J., Homans S. W., McConville M. J. Evolutionary aspects of GPI metabolism in kinetoplastid parasites. Cell Biol Int Rep. 1991 Nov;15(11):991–1005. doi: 10.1016/0309-1651(91)90052-k. [DOI] [PubMed] [Google Scholar]
  5. Ferguson M. A. What can GPI do for you? Parasitol Today. 1994 Feb;10(2):48–52. doi: 10.1016/0169-4758(94)90392-1. [DOI] [PubMed] [Google Scholar]
  6. Homans S. W., Edge C. J., Ferguson M. A., Dwek R. A., Rademacher T. W. Solution structure of the glycosylphosphatidylinositol membrane anchor glycan of Trypanosoma brucei variant surface glycoprotein. Biochemistry. 1989 Apr 4;28(7):2881–2887. doi: 10.1021/bi00433a020. [DOI] [PubMed] [Google Scholar]
  7. Masterson W. J., Doering T. L., Hart G. W., Englund P. T. A novel pathway for glycan assembly: biosynthesis of the glycosyl-phosphatidylinositol anchor of the trypanosome variant surface glycoprotein. Cell. 1989 Mar 10;56(5):793–800. doi: 10.1016/0092-8674(89)90684-3. [DOI] [PubMed] [Google Scholar]
  8. McConville M. J., Ferguson M. A. The structure, biosynthesis and function of glycosylated phosphatidylinositols in the parasitic protozoa and higher eukaryotes. Biochem J. 1993 Sep 1;294(Pt 2):305–324. doi: 10.1042/bj2940305. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Pingel S., Duszenko M. Identification of two distinct galactosyltransferase activities acting on the variant surface glycoprotein of Trypanosoma brucei. Biochem J. 1992 Apr 15;283(Pt 2):479–485. doi: 10.1042/bj2830479. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES