کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10972832 | 1107325 | 2009 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Genetic identification of essential indels and domains in carbamoyl phosphate synthetase II of Toxoplasma gondii
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موضوعات مرتبط
علوم زیستی و بیوفناوری
ایمنی شناسی و میکروب شناسی
انگل شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
New treatments need to be developed for the significant human diseases of toxoplasmosis and malaria to circumvent problems with current treatments and drug resistance. Apicomplexan parasites causing these lethal diseases are deficient in pyrimidine salvage, suggesting that selective inhibition of de novo pyrimidine biosynthesis can lead to a severe loss of uridine 5â²-monophosphate (UMP) and thymidine 5â²-monophosphate (dTMP) pools, thereby inhibiting parasite RNA and DNA synthesis. Disruption of Toxoplasma gondii carbamoyl phosphate synthetase II (CPSII) induces a severe uracil auxotrophy with no detectable parasite replication in vitro and complete attenuation of virulence in mice. Here we show that a CPSII cDNA minigene efficiently complements the uracil auxotrophy of CPSII-deficient mutants, restoring parasite growth and virulence. Our complementation assays reveal that engineered mutations within, or proximal to, the catalytic triad of the N-terminal glutamine amidotransferase (GATase) domain inactivate the complementation activity of T. gondii CPSII and demonstrate a critical dependence on the apicomplexan CPSII GATase domain in vivo. Surprisingly, indels present within the T. gondii CPSII GATase domain as well as the C-terminal allosteric regulatory domain are found to be essential. In addition, several mutations directed at residues implicated in allosteric regulation in Escherichia coli CPS either abolish or markedly suppress complementation and further define the functional importance of the allosteric regulatory region. Collectively, these findings identify novel features of T. gondii CPSII as potential parasite-selective targets for drug development.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal for Parasitology - Volume 39, Issue 5, April 2009, Pages 533-539
Journal: International Journal for Parasitology - Volume 39, Issue 5, April 2009, Pages 533-539
نویسندگان
Barbara A. Fox, Jessica G. Ristuccia, David J. Bzik,