3'-5' exonuclease that prefers single-stranded DNA and RNA. May play a role in the H(2)O(2)-induced DNA damage repair. No activity in the presence of Ca(2+) or Zn(2+). Monomer. Constitutively expressed. Knockout cells are less resistant to the DNA damaging agent H(2)O(2). Belongs to the metallo-dependent hydrolases superfamily. TatD-type hydrolase family. TatD subfamily. Was suggested to be a central component of a quality control system that is linked to the Tat translocation system (PubMed:19343049). However, it was shown later that malfolded Tat substrates are Tat-independently degraded and that TatD is not involved in quality control of the Tat substrates (PubMed:20659466). Extended N-terminus.