Purine salvage pathways in the apicomplexan parasite Toxoplasma gondii

Kshitiz Chaudhary, John A. Darling, Leah M. Fohl, William Sullivan, Robert G K Donald, Elmer R. Pfefferkorn, Buddy Ullman, David S. Roost

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

We have exploited a variety of molecular genetic, biochemical, and genomic techniques to investigate the roles of purine salvage enzymes in the protozoan parasite Toxoplasma gondii. The ability to generate defined genetic knockouts and target transgenes to specific loci demonstrates that T. gondii uses two (and only two) pathways for purine salvage, defined by the enzymes hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) and adenosine kinase (AK). Both HXGPRT and AK are single-copy genes, and either one can be deleted, indicating that either one of these pathways is sufficient to meet parasite purine requirements. Fitness defects suggest both pathways are important for the parasite, however, and that the salvage of adenosine is more important than salvage of hypoxanthine and other purine nucleobases. HXGPRT and AK cannot be deleted simultaneously unless one of these enzymes is provided in trans, indicating that alternative routes of functionally significant purine salvage are lacking. Despite previous reports to the contrary, we found no evidence of adenine phosphoribosyltransferase (APRT) activity when parasites were propagated in APRT-deficient host cells, and no APRT ortholog is evident in the T. gondii genome. Expression of Leishmania donovani APRT in transgenic T. gondii parasites yielded low levels of activity but did not permit genetic deletion of both HXGPRT and AK. A detailed comparative genomic study of the purine salvage pathway in various apicomplexan species highlights important differences among these parasites.

Original languageEnglish (US)
Pages (from-to)31221-31227
Number of pages7
JournalJournal of Biological Chemistry
Volume279
Issue number30
DOIs
StatePublished - Jul 23 2004
Externally publishedYes

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Salvaging
Toxoplasma
Adenine Phosphoribosyltransferase
Adenosine Kinase
Parasites
Enzymes
Genes
Leishmania donovani
Hypoxanthine
Transgenes
Adenosine
purine
Molecular Biology
Genome
Defects
hypoxanthine-guanine-xanthine phosphoribosyltransferase

ASJC Scopus subject areas

  • Biochemistry

Cite this

Chaudhary, K., Darling, J. A., Fohl, L. M., Sullivan, W., Donald, R. G. K., Pfefferkorn, E. R., ... Roost, D. S. (2004). Purine salvage pathways in the apicomplexan parasite Toxoplasma gondii. Journal of Biological Chemistry, 279(30), 31221-31227. https://doi.org/10.1074/jbc.M404232200

Purine salvage pathways in the apicomplexan parasite Toxoplasma gondii. / Chaudhary, Kshitiz; Darling, John A.; Fohl, Leah M.; Sullivan, William; Donald, Robert G K; Pfefferkorn, Elmer R.; Ullman, Buddy; Roost, David S.

In: Journal of Biological Chemistry, Vol. 279, No. 30, 23.07.2004, p. 31221-31227.

Research output: Contribution to journalArticle

Chaudhary, K, Darling, JA, Fohl, LM, Sullivan, W, Donald, RGK, Pfefferkorn, ER, Ullman, B & Roost, DS 2004, 'Purine salvage pathways in the apicomplexan parasite Toxoplasma gondii', Journal of Biological Chemistry, vol. 279, no. 30, pp. 31221-31227. https://doi.org/10.1074/jbc.M404232200
Chaudhary K, Darling JA, Fohl LM, Sullivan W, Donald RGK, Pfefferkorn ER et al. Purine salvage pathways in the apicomplexan parasite Toxoplasma gondii. Journal of Biological Chemistry. 2004 Jul 23;279(30):31221-31227. https://doi.org/10.1074/jbc.M404232200
Chaudhary, Kshitiz ; Darling, John A. ; Fohl, Leah M. ; Sullivan, William ; Donald, Robert G K ; Pfefferkorn, Elmer R. ; Ullman, Buddy ; Roost, David S. / Purine salvage pathways in the apicomplexan parasite Toxoplasma gondii. In: Journal of Biological Chemistry. 2004 ; Vol. 279, No. 30. pp. 31221-31227.
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