Projects per year
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 language | English |
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Pages (from-to) | 15256-15267 |
Number of pages | 12 |
Journal | Journal of Biological Chemistry |
Volume | 288 |
Issue number | 21 |
Early online date | 21 Mar 2013 |
DOIs | |
Publication status | Published - 24 May 2013 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology
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Dive into the research topics of 'Allosteric activation of trypanosomatid deoxyhypusine synthase by a catalytically dead paralog'. Together they form a unique fingerprint.Projects
- 2 Finished
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Aref#d: 19815. Wellcome Trust Centre for Drug Discovery (Strategic Award)
Fairlamb, A. (Investigator), Ferguson, M. (Investigator) & Frearson, J. (Investigator)
1/01/08 → 31/12/12
Project: Research
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Aref#d: 18185. Characterization and validation of drug targets in the Kinetoplastida (Principal Research Fellowship/Programme Grant)
Fairlamb, A. (Investigator)
1/10/06 → 30/09/17
Project: Research