<p>This is a conserved region from DNA primase. This corresponds to the Toprim (topoisomerase-primase) domain common to DnaG primases, topoisomerases, OLD family nucleases and RecR/M DNA repair proteins [<cite idref="PUB00005780"/>]. Both DnaG motifs IV and V are present in the alignment, the DxD (V) motif may be involved in Mg2+ binding and mutations to the conserved glutamate (IV) completely abolish DnaG type primase activity. DNA primase <db_xref db="EC" dbkey="2.7.7.6"/> is a nucleotidyltransferase it synthesizes the oligoribonucleotide primers required for DNA replication on the lagging strand of the replication fork; it can also prime the leading stand and has been implicated in cell division [<cite idref="PUB00001839"/>]. This family also includes the atypical archaeal A subunit from type II DNA topoisomerases [<cite idref="PUB00004485"/>]. Type II DNA topoisomerases catalyse the relaxation of DNA supercoiling by causing transient double strand breaks.</p>