(A) Schematic of DnaA, DnaD, DnaB, DnaC, and DnaI divided into their individual domains. Amino acid boundaries of each protein fragment are indicated. WHD = Winged Helix Domain; CTD = C-terminal Domain; NTD = N-terminal Domain; ZBD = Zinc Binding Domain. (B) SDS-polyacrylamide gel showing purified domains from DnaD and DnaB. (C) B2H of T25-tagged DnaA domains co-expressed with T18-tagged full-length YabA (YabAFL), full-length SirA (SirAFL), or the domains from DnaD. (D) B2H of T25-tagged DnaB domains co-expressed with T18-tagged DnaD domains. (E) B2H of T25-tagged DnaI or DnaB domains co-expressed with T18-tagged DnaC domains. (F) B2H of T25-tagged DnaB domains co-expressed with T18-tagged DnaI domains.