Cloning and characterisation of the UDP-glucose 4 '-epimerase of Trypanosoma cruzi

Janine R. Roper, Michael A. J. Ferguson

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    23 Citations (Scopus)

    Abstract

    Trypanosoma cruzi incorporates galactose into many of its cell-surface glycoconjugates but it is unable to transport this sugar through its hexose transporter. Epimerisation of UDP-glucose to UDP-galactose by UDP-glucose 4'-epimerase may be the only way that the parasites can obtain galactose. Here, we describe cloning the T. cruzi UDP-Glc 4'-epimerase (TcGALE) gene and show that it is functional by complementing an Escherichia coli epimerase-deficient strain. The T. cruzi GALE gene encodes a 42.4 kDa protein and the recombinant protein expressed in E. coli is a homodimer in solution with a specific activity of 3.8 U mg(-1) and K-m for UDP-Gal of 114 µM. Unlike the human epimerase. T. cruzi UDP-Glc 4'-epimerase is unable to inter-convert UDP-N-acetylglucosamine and UDP-N-acetylgalactosamine. This may explain why T. cruzi initiates O-glycosylation of its abundant GPI-anchored surface mucins via GlcNAcalpha1-O-Thr/Ser rather than the GalNAcalpha1-O-Thr/Ser linkage that is common for mucins from many other eukaryotes. (C) 2003 Elsevier B.V. All rights reserved.

    Original languageEnglish
    Pages (from-to)47-53
    Number of pages7
    JournalMolecular and Biochemical Parasitology
    Volume132
    Issue number1
    DOIs
    Publication statusPublished - Nov 2003

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