Plays a key role in the initiation and regulation of chromosomal replication. Binds in an ATP-dependent fashion to the origin of replication (oriC) to initiate formation of the DNA replication initiation complex exactly once per cell cycle. Binds the DnaA box (consensus sequence 5'-TTATC[CA]A[CA]A-3'); subsequent binding of DNA polymerase III subunits leads to replisome formation. The DnaA-ATP form converts to DnaA-ADP; once converted to ADP the protein cannot initiate replication, ensuring only 1 round of replication per cell cycle. DnaA can inhibit its own gene expression as well as that of other genes such as dam, rpoH, ftsA and mioC. Also required for replication of plasmid DNA; binds 4 dnaA boxes in the minimal plasmid RK2 replication origin (oriV). Acetylation decreases the binding abilities to ATP and ADP and leads to inhibition of DNA replication initiation. Some 20 DnaA protein molecules bind their sites in oriC. Forms the RIDA (regulatory inactivation of DnaA) complex with ATP-DnaA, ADP-Hda and the DNA-loaded sliding beta clamp (dnaN). Interacts with DiaA; this stimulates the association of DnaA with the origin of replication. Acetylated at Lys-178 by PatZ. Deacetylated by CobB. Is also acetylated nonenzymatically by acetyl-phosphate. Acetylation level increases in a growth phase-dependent manner and peaks at the stationnary phase. At least 4 systems specifically target DnaA to prevent more than 1 round of replication initiation per cell cycle. 1: SeqA binds to and sequesters hemimethylated oriC, preventing DnaA binding. 2: ATP-DnaA binds to the chromosomal datA locus, sequestering ATP-DnaA. 3: ATP-DnaA binds to its own promoter, repressing transcription. 4: RIDA (regulatory inactivation of DnaA) via Hda and the DNA-loaded beta clamp hydrolyzes ATP-DnaA to ADP-DnaA. Belongs to the DnaA family. Extended N-terminus.