Allosteric activation of trypanosomatid deoxyhypusine synthase by a catalytically dead paralog

Suong Nguyen, Deuan C. Jones, Susan Wyllie, Alan H. Fairlamb, Margaret A. Phillips

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Polyamine biosynthesis is a key drug target in African trypanosomes. The "resurrection drug" eflornithine (difluoromethylornithine), which is used clinically to treat human African trypanosomiasis, inhibits the first step in polyamine (spermidine) biosynthesis, a highly regulated pathway in most eukaryotic cells. Previously, we showed that activity of a key trypanosomatid spermidine biosynthetic enzyme, S-adenosylmethionine decarboxylase, is regulated by heterodimer formation with a catalytically dead paralog (a prozyme). Here, we describe an expansion of this prozyme paradigm to the enzyme deoxyhypusine synthase, which is required for spermidine-dependent hypusine modification of a lysine residue in the essential translation factor eIF5A. Trypanosoma brucei encodes two deoxyhypusine synthase paralogs, one that is catalytically functional but grossly impaired, and the other is inactive. Co-expression in Escherichia coli results in heterotetramer formation with a 3000-fold increase in enzyme activity. This functional complex is also present in T. brucei, and conditional knock-out studies indicate that both DHS genes are essential for in vitro growth and infectivity in mice. The recurrent evolution of paralogous, catalytically dead enzyme-based activating mechanisms may be a consequence of the unusual gene expression in the parasites, which lack transcriptional regulation. Our results suggest that this mechanism may be more widely used by trypanosomatids to control enzyme activity and ultimately influence pathogenesis than currently appreciated.

Original languageEnglish (US)
Pages (from-to)15256-15267
Number of pages12
JournalJournal of Biological Chemistry
Volume288
Issue number21
DOIs
StatePublished - May 24 2013

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Spermidine
Eflornithine
Chemical activation
Biosynthesis
Polyamines
Enzyme activity
Enzymes
Adenosylmethionine Decarboxylase
Trypanosoma brucei brucei
Gene expression
Pharmaceutical Preparations
Escherichia coli
Lysine
African Trypanosomiasis
Genes
Trypanosomiasis
Essential Genes
Eukaryotic Cells
Parasites
deoxyhypusine synthase

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Allosteric activation of trypanosomatid deoxyhypusine synthase by a catalytically dead paralog. / Nguyen, Suong; Jones, Deuan C.; Wyllie, Susan; Fairlamb, Alan H.; Phillips, Margaret A.

In: Journal of Biological Chemistry, Vol. 288, No. 21, 24.05.2013, p. 15256-15267.

Research output: Contribution to journalArticle

Nguyen, Suong ; Jones, Deuan C. ; Wyllie, Susan ; Fairlamb, Alan H. ; Phillips, Margaret A. / Allosteric activation of trypanosomatid deoxyhypusine synthase by a catalytically dead paralog. In: Journal of Biological Chemistry. 2013 ; Vol. 288, No. 21. pp. 15256-15267.
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