HIGH-AFFINITY BINDING-SITES FOR THE INITIATOR PROTEIN DNAA ON THE CHROMOSOME OF ESCHERICHIA-COLI

The initiator protein DnaA of Escherichia coli binds with unusually hi gh affinity to five regions on the chromosome, in addition to the repl ication origin, oriC. Using a solid-phase DNA binding assay, in which the DNA binding C-terminal domain of DnaA is bound via a biotin tag to magnetic beads, we could fish only fragments with these six regions f rom different chromosomal digests. Except for oriC, these fragments co ntain only one or two consensus DnaA binding sites, DnaA boxes. The di stribution of these high-affinity DnaA boxes on the chromosome is rand om.