Identification of tyrosine as a functional residue in the active site of Escherichia coli dUTPase

Beata G. Vertessy, Petra Zalud, Per O. Nyman, Michael Zeppezauer

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26 Citations (Scopus)


dUTP nucleotidohydrolase (dUTPase, EC from E. coli contains a total of six tyrosine residues per trimer. About half of them were found to be susceptible to acetylation with N-acetylimidazole or to nitration with tetranitromethane with concomitant loss of activity. Deacetylation with N-hydroxylamine leads to full reactivation. Inhibitory products of dUTP hydrolysis, i.e., dUMP and inorganic pyrophosphate together with the cofactor Mg2+ protect significantly against inactivation and chemical modification. In the Cu2+-dUTPase complex, charge transfer from Cu2+ to the tyrosinate anion was perturbed by the presence of the substrate dUTP. These results, together with the occurrence of one tyrosine residue in a strictly conserved sequence motif suggest the critical importance of this residue for the function of the enzyme.

Original languageEnglish
Pages (from-to)146-150
Number of pages5
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number1
Publication statusPublished - Mar 16 1994



  • (E. coli)
  • Copper-tyrosinate charge-transfer complex
  • Nitrotyrosine spectral titration
  • Tyrosinate charge-transfer complex, copper
  • Tyrosine modification
  • dUTPase

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology

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