title: DnaA binding locus datA promotes DnaA-ATP hydrolysis to enable cell cycle-coordinated replication initiation.
abstract: The initiation of chromosomal DNA replication is rigidly regulated to ensure that it occurs in a cell cycle-coordinated manner. To ensure this in Escherichia coli, multiple systems regulate the activity of the replication initiator ATP-DnaA. The level of ATP-DnaA increases before initiation after which it drops via DnaA-ATP hydrolysis, yielding initiation-inactive ADP-DnaA. DnaA-ATP hydrolysis is crucial to regulation of initiation and mainly occurs by a replication-coupled feedback mechanism named RIDA (regulatory inactivation of DnaA). Here, we report a second DnaA-ATP hydrolysis system that occurs at the chromosomal site datA. This locus has been annotated as a reservoir for DnaA that binds many DnaA molecules in a manner dependent upon the nucleoid-associated factor IHF (integration host factor), resulting in repression of untimely initiations; however, there is no direct evidence for the binding of many DnaA molecules at this locus. We reveal that a complex consisting of datA and IHF promotes DnaA-ATP hydrolysis in a manner dependent on specific inter-DnaA interactions. Deletion of datA or the ihf gene increased ATP-DnaA levels to the maximal attainable levels in RIDA-defective cells. Cell-cycle analysis suggested that IHF binds to datA just after replication initiation at a time when RIDA is activated. We propose a model in which cell cycle-coordinated ATP-DnaA inactivation is regulated in a concerted manner by RIDA and datA.
authors.affiliation: Department of Molecular Biology, Graduate School of Pharmaceutical Sciences,  Kyushu University, Fukuoka 812-8582,  Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Kasho
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Katayama
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002453:Cell Cycle; D002876:Chromosomes, Bacterial / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics / Q000502:physiology*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D006868:Hydrolysis; D034982:Integration Host Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D051738:Origin Recognition Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; D034982:Integration Host Factors; C114650:OriC chromosomal replication origin; D051738:Origin Recognition Complex; C440502:integration host factor, E coli; D000255:Adenosine Triphosphate