<p>Members of this uncharacterised family share a motif approximating DXH(X25)GDXXD(X25)GNHD as found in several phosphoesterases, including the nucleases SbcD and Mre11. SbcD is a subunit of the SbcCD nuclease of <taxon tax_id="562">Escherichia coli</taxon> that can cleave DNA hairpins to unblock stalled DNA replication. All members of this family are archaeal.</p>