Identification of a second catalytically active trans-sialidase in Trypanosoma brucei

Biochem Biophys Res Commun. 2011 Nov 18;415(2):421-5. doi: 10.1016/j.bbrc.2011.10.085. Epub 2011 Oct 21.

Abstract

The procyclic stage of Trypanosoma brucei is covered by glycosylphosphatidylinositol (GPI)-anchored surface proteins called procyclins. The procyclin GPI anchor contains a side chain of N-acetyllactosamine repeats terminated by sialic acids. Sialic acid modification is mediated by trans-sialidases expressed on the parasite's cell surface. Previous studies suggested the presence of more than one active trans-sialidases, but only one has so far been reported. Here we cloned and examined enzyme activities of four additional trans-sialidase homologs, and show that one of them, Tb927.8.7350, encodes another active trans-sialidase, designated as TbSA C2. In an in vitro assay, TbSA C2 utilized α2-3 sialyllactose as a donor, and produced an α2-3-sialylated product, suggesting that it is an α2-3 trans-sialidase. We suggest that TbSA C2 plays a role in the sialic acid modification of the trypanosome cell surface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Sugars / chemistry
  • Catalysis
  • Cell Membrane / metabolism
  • Cloning, Molecular
  • Glycoproteins / chemistry
  • Glycoproteins / genetics
  • Glycoproteins / metabolism*
  • Glycosylphosphatidylinositols / chemistry
  • Glycosylphosphatidylinositols / metabolism
  • Mutation
  • N-Acetylneuraminic Acid / chemistry
  • N-Acetylneuraminic Acid / metabolism*
  • Neuraminidase / chemistry
  • Neuraminidase / genetics
  • Neuraminidase / metabolism*
  • Trypanosoma brucei brucei / enzymology*
  • Trypanosoma brucei brucei / genetics

Substances

  • Amino Sugars
  • Glycoproteins
  • Glycosylphosphatidylinositols
  • N-acetyllactosamine
  • trans-sialidase
  • Neuraminidase
  • N-Acetylneuraminic Acid