This domain is found in E.coli primosomal protein 1 (Pp1). PP1 domain (residues 84-153) in Swiss:P0A8J2 can bind to different types of ssDNA, which is fundamental for its physiological substrate bindings. Functional analysis indicate that both N- and C- terminals are essential to having the cooperative effect in binding ssDNA. The ssDNA bound complex displays a spiral filament assembly that is adopted by many proteins that are involved in DNA replication, such as DnaA, RecA and PriB. This domain is similar to Pfam:PF08585 except that it contains an extra loop at the N-terminus (84-99). Structural analysis indicate that this extra loop might be essential for the stabilisation of the three-helix bundle [1].

1: Structure and mechanism of the primosome protein DnaT-functional structures for homotrimerization, dissociation of ssDNA from the PriB.ssDNA complex, and formation of the DnaT.ssDNA complex. Fujiyama S, Abe Y, Tani J, Urabe M, Sato K, Aramaki T, Katayama T, Ueda T; FEBS J. 2014;281:5356-5370. PMID:25265331

2: Crystal structure of DnaT84-153-dT10 ssDNA complex reveals a novel single-stranded DNA binding mode. Liu Z, Chen P, Wang X, Cai G, Niu L, Teng M, Li X; Nucleic Acids Res. 2014;42:9470-9483. PMID:25053836