<p>This family includes the replicative DNA helicases, helicase DnaB, which exhibit DNA-dependent ATPase activity. Helicase DnaB is a homohexameric protein required for DNA replication. The homohexamer can form a ring around a single strand of DNA near a replication fork. An intein of more than 400 residues is found at a conserved location in DnaB of Synechocystis PCC6803, <taxon tax_id="29549">Rhodothermus marinus</taxon> (both experimentally confirmed), and <taxon tax_id="1773">Mycobacterium tuberculosis</taxon>. The intein removes itself by a self-splicing reaction. Replication protein, GP12 from <taxon tax_id="10754">Enterobacteria phage P22</taxon> also belongs to this family [<cite idref="PUB00019435"/>].</p>