A molecular docking strategy identifies eosin B as a non-active site inhibitor of protozoal bifunctional thymidylate synthase-dihydrofolate reductase

Chloé E. Atreya, Eric F. Johnson, John J. Irwin, Antonia Dow, Kristen M. Massimine, Isabelle Coppens, Valeska Stempliuk, Stephen Beverley, Keith A. Joiner, Brian K. Shoichet, Karen S. Anderson

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Protozoal parasites are unusual in that their thymidylate synthase (TS) and dihydrofolate reductase (DHFR) enzymes exist on a single polypeptide. In an effort to probe the possibility of substrate channeling between the TS and DHFR active sites and to identify inhibitors specific for bifunctional TS-DHFR, we used molecular docking to screen for inhibitors targeting the shallow groove connecting the two active sites. Eosin B is a 100 μM non-active site inhibitor of Leishmania major TS-DHFR identified by molecular docking. Eosin B slows both the TS and DHFR reaction rates. When Arg-283, a key residue to which eosin B is predicted to bind, is mutated to glutamate, however, eosin B only minimally inhibits the TS-DHFR reaction. Additionally, eosin B was found to be a 180 μM inhibitor of Toxoplasma gondii in both biochemical and cell culture assays.

Original languageEnglish (US)
Pages (from-to)14092-14100
Number of pages9
JournalJournal of Biological Chemistry
Volume278
Issue number16
DOIs
StatePublished - Apr 18 2003

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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