Discovery of potent and selective inhibitors of toxoplasma gondii thymidylate synthase for opportunistic infections

Nilesh Zaware, Hitesh Sharma, Jie Yang, Ravi Kumar Vyas Devambatla, Sherry F. Queener, Karen S. Anderson, Aleem Gangjee

Research output: Contribution to journalArticle

16 Scopus citations


Infection by the parasite Toxoplasma gondii (tg) can lead to toxoplasmosis in immunocompromised patients such as organ transplant, cancer, and HIV/AIDS patients. The bifunctional thymidylate synthase-dihydrofolate reductase (TS-DHFR) enzyme is crucial for nucleotide synthesis in T. gondii and represents a potential target to combat T. gondii infection. While species selectivity with drugs has been attained for DHFR, TS is much more conserved across species, and specificity is significantly more challenging. We discovered novel substituted-9H-pyrimido[4,5-b]indoles 1-3 with single-digit nanomolar K i for tgTS, two of which, 2 and 3, are 28- and 122-fold selective over human TS (hTS). The synthesis of these compounds, and their structures in complex with tgTS-DHFR are presented along with binding measurements and cell culture data. These results show, for the very first time, that, in spite of the high degree of conservation of active site residues between hTS and the parasite TS, specificity has been accomplished via novel structures and provides a new target (TS) for selective drug development against parasitic infections.

Original languageEnglish (US)
Pages (from-to)1148-1151
Number of pages4
JournalACS Medicinal Chemistry Letters
Issue number12
StatePublished - Dec 12 2013


  • active-site inhibitors
  • crystal structure
  • Opportunistic infection
  • thymidylate-synthase inhibitors
  • Toxoplasma gondii

ASJC Scopus subject areas

  • Organic Chemistry
  • Drug Discovery
  • Biochemistry

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