DnaA is a protein that controls the initiation of DNA replication in bacteria. It can be in either an ATP- or ADP- bound form, with DnaA-ATP being the active form.
In order for replication to occur, the ratio of DnaA-ATP : DnaA-ADP must reach a certain level before being able to initiate. Where the level of DnaA-ADP is too high, the cell is in the eclipse period. During this time, it is not possible to initiate DNA replication, due to there not being adequate ATP in the cell. The ATP in the cell must be replenished prior to starting the replication, with the ratio determining whether there is adequate ATP to complete DNA replication.
Hemi-methylated DNA attracts DnaA-ATP, bringing it into closer proximity to the DNA for it to be ready and in high concentration when the DNA polymerase translocates along.