Members of this family adopt a structure consisting of a core of antiparallel beta sheets. They are found in various bacterial hypothetical proteins, and have been shown to harbour both primase and polymerase activities [1].

1: Structure of a bifunctional DNA primase-polymerase. Lipps G, Weinzierl AO, von Scheven G, Buchen C, Cramer P; Nat Struct Mol Biol. 2004;11:157-162. PMID:14730355