Service interruption on Monday 11 July from 12:30 to 13:00: all the sites of the CCSD (HAL, EpiSciences, SciencesConf, AureHAL) will be inaccessible (network hardware connection).
Skip to Main content Skip to Navigation
Journal articles

The trans-sialidase from the African trypanosome Trypanosoma brucei

Abstract : Trypanosoma brucei is the cause of the diseases known as sleeping sickness in humans (T. brucei ssp. gambiense and ssp. rhodesiense) and ngana in domestic animals (T. brucei brucei) in Africa. Procyclic trypomastigotes, the tsetse vector stage, express a surface-bound trans-sialidase that transfers sialic acid to the glycosylphosphatidylinositol anchor of procyclin, a surface glycoprotein covering the parasite surface. Trans-sialidase is a unique enzyme expressed by a few trypanosomatids that allows them to scavenge sialic acid from sialylated compounds present in the infected host. The only enzyme extensively characterized is that of the American trypanosome T. cruzi (TcTS). In this work we identified and characterized the gene encoding the trans-sialidase from T. brucei brucei (TbTS). TbTS genes are present at a small copy number, at variance with American trypanosomes where a large gene family is present. The recombinant TbTS protein has both sialidase and trans-sialidase activity, but it is about 10 times more efficient in transferring than in hydrolysing sialic acid. Its N-terminus contains a region of 372 amino acids that is 45% identical to the catalytic domain of TcTS and contains the relevant residues required for catalysis. The enzymatic activity of mutants at key positions involved in the transfer reaction revealed that the catalytic sites of TcTS and TbTS are likely to be similar, but are not identical. As in the case of TcTS and TrSA, the substitution of a conserved tryptophanyl residue changed the substrate specificity rendering a mutant protein capable of hydrolysing both alpha-(2,3) and alpha-(2,6)-linked sialoconjugates.
Complete list of metadata

Cited literature [43 references]  Display  Hide  Download
Contributor : Alejandro Buschiazzo Connect in order to contact the contributor
Submitted on : Friday, April 24, 2020 - 11:28:23 PM
Last modification on : Thursday, April 7, 2022 - 10:10:27 AM




Georgina Montagna, M. Laura Cremona, Gastón Paris, María Fernanda Amaya, Alejandro Buschiazzo, et al.. The trans-sialidase from the African trypanosome Trypanosoma brucei. European Journal of Biochemistry, Wiley, 2002, 269 (12), pp.2941-2950. ⟨10.1046/j.1432-1033.2002.02968.x⟩. ⟨pasteur-02554091⟩



Record views