Active site closure facilitates juxtaposition of reactant atoms for initiation of catalysis by human dUTPase

Balázs Varga, Orsolya Barabás, Júlia Kovári, Judit Tóth, Éva Hunyadi-Gulyás, Éva Klement, Katalin F. Medzihradszky, Ferenc Tölgyesi, Judit Fidy, Beáta G. Vértessy

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Human dUTPase, essential for DNA integrity, is an important survival factor for cancer cells. We determined the crystal structure of the enzyme:α,β-imino-dUTP:Mg complex and performed equilibrium binding experiments in solution. Ordering of the C-terminus upon the active site induces close juxtaposition of the incoming nucleophile attacker water oxygen and the α-phosphorus of the substrate, decreasing their distance below the van der Waals limit. Complex interactions of the C-terminus with both substrate and product were observed via a specifically designed tryptophan sensor, suitable for further detailed kinetic and ligand binding studies. Results explain the key functional role of the C-terminus.

Original languageEnglish
Pages (from-to)4783-4788
Number of pages6
JournalFEBS letters
Volume581
Issue number24
DOIs
Publication statusPublished - Oct 2 2007

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Keywords

  • Enzyme mechanism
  • Flexible C-terminus
  • High-throughput screening for ligand binding
  • Initiation of catalysis
  • Tryptophan sensor

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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