Escherichia coli Orf135 hydrolyzes oxidatively damaged nucleotides such as 2-hydroxy-dATP, 8-oxo-dGTP and 5-hydroxy-CTP, in addition to 5-methyl-dCTP, dCTP and CTP. Nucleotide pool sanitization by Orf135 is important since nucleotides are continually subjected to potential damage by reactive oxygen species produced during respiration. Orf135 is a member of the Nudix family of proteins which hydrolyze nucleoside diphosphate derivatives. Nudix hydrolases are characterized by the presence of a conserved motif, even though they recognize various substrates and possess a variety of substrate binding pockets. We investigated the tertiary structure of Orf135 and its interaction with a 2-hydroxy-dATP analog using NMR. We report on the solution structure of Orf135, which should contribute towards a structural understanding of Orf135 and its interaction with substrates. (C) 2012 Elsevier Inc. All rights reserved.