The Rep family helicases are composed of four structural domains. The Rep family function as dimers. REP helicases catalyse ATP dependent unwinding of double stranded DNA to single stranded DNA. P23478 P08394 have large insertions near to the carboxy-terminus relative to other members of the family.
Helicases have been classified in 5 superfamilies (SF1-SF5). All of the proteins bind ATP and, consequently, all of them carry the classical Walker A (phosphate-binding loop or P-loop) and Walker B (Mg2+-binding aspartic acid) motifs. For the two largest groups, commonly referred to as SF1 and SF2, a total of seven characteristic motifs have been identified [PUBMED:2546125] which are distributed over two structural domains, an N-terminal ATP-binding domain and a C-terminal domain. UvrD-like DNA helicases belong to SF1, but they differ from classical SF1/SF2 by a large insertion in each domain. UvrD-like DNA helicases unwind DNA with a 3'-5' polarity [PUBMED:10679457].