Transketolase in Trypanosoma brucei

Stoffel, S.A., Alibu, V.P., Hubert, J., Ebikeme, C., Portais, J.C., Bringaud, F., Schweingruber, M.E. and Barrett, M. (2011) Transketolase in Trypanosoma brucei. Molecular and Biochemical Parasitology, 179(1), pp. 1-7. (doi:10.1016/j.molbiopara.2011.04.006)

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Publisher's URL: http://dx.doi.org/10.1016/j.molbiopara.2011.04.006

Abstract

A single copy gene, encoding a protein highly similar to transketolase from other systems, was identified in the Trypanosoma brucei genome. The gene was expressed in E. coli and the purified protein demonstrated transketolase activity with Km values of 0.2 mM and 0.8 mM respectively for xylulose 5-phosphate and ribose 5-phosphate. A peroxisomal targeting signal (PTS-1) present at the C-terminus of the protein suggested a glycosomal localisation. However, subcellular localisation experiments revealed that while the protein was present in glycosomes it was found mainly within the cytosol and thus has a dual localisation. Transketolase activity was absent from the long slender bloodstream form of the parasite and the protein was not detectable in this life cycle stage, with the RNA present only at low abundance, indicating a strong differential regulation, being present predominantly in the procyclic form. The gene was knocked out from procyclic T. brucei and transketolase activity was lost but no growth phenotype was evident in the null mutants. Metabolite profiling to compare wild type and TKT null mutants revealed substantial increases in transketolase substrate metabolites coupled to loss of sedoheptulose 7-phosphate, a principal product of the transketolase reaction.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Barrett, Professor Michael and Alibu, Dr Vincent
Authors: Stoffel, S.A., Alibu, V.P., Hubert, J., Ebikeme, C., Portais, J.C., Bringaud, F., Schweingruber, M.E., and Barrett, M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Molecular and Biochemical Parasitology
Publisher:Elsevier BV
ISSN:0166-6851
ISSN (Online):1872-9428
Published Online:01 September 2011

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