<p>This domain forms a ribonuclease H fold consisting of two beta sheets and one alpha helix, arranged as a beta-alpha-beta motif. Each beta sheet has five strands, arranged in a 32145 order, with the second strand being antiparallel to the rest. They are capable of resolving Holliday junctions and cleave DNA after 5'-CT-3, and 5'-TT-3, sequences [<cite idref="PUB00026683"/>]. This entry also includes a domain found in the mitochondrial RNA-splicing protein MRS1 which is involved in the excision of group I introns [<cite idref="PUB00055561"/>, <cite idref="PUB00055559"/>].</p>