DEDDy 3'-5' exonuclease domain of Caenorhabditis elegans mut-7 and similar proteins
The mut-7 subfamily is composed of Caenorhabditis elegans mut-7 and similar proteins found in plants and metazoans. Mut-7 is implicated in posttranscriptional gene silencing. It contains a DEDDy-type DnaQ-like 3'-5' exonuclease domain possessing three conserved sequence motifs, termed ExoI, ExoII and ExoIII, with a specific YX(3)D pattern at ExoIII. These motifs are clustered around the active site and contain four conserved acidic residues that serve as ligands for the two metal ions required for catalysis.