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Cysteine Residues Contribute To The Dimerization And Enzymatic Activity Of Human Nuclear Dutp Nucleotidohydrolase (Ndut)., Shawna M Rotoli, Julia L Jones, Salvatore J Caradonna

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

dUTPase is an enzyme found in all organisms that have thymine as a constituent of DNA. Through evolution, humans have two major isoforms of dUTPase: a mitochondrial (mDut) and a nuclear (nDut) isoform. The nuclear isoform of dUTPase is a 164-amino-acids-long protein containing three cysteine residues. nDut's starting methionine is post-translationally cleaved, leaving four unique amino acids on its amino-terminus including one cysteine residue (C3). These are not present in the mitochondrial isoform (mDut). Using mass spectrometry analyses of recombinant dUTPase constructs, we have discovered an intermolecular disulfide bridge between cysteine-3 of each nDut monomer. We have found that these …