The initiator function of DnaA protein is negatively regulated by the sliding clamp of the E. coli chromosomal replicase.
The beta subunit of DNA polymerase III is essential for negative regulation of the initiator protein, DnaA. DnaA inactivation occurs through accelerated hydrolysis of ATP bound to DnaA; the resulting ADP-DnaA fails to initiate replication. The ability of beta subunit to promote DnaA inactivation depends on its assembly as a sliding clamp on DNA and must be accompanied by a partially purified factor, IdaB protein. DnaA inactivation in the presence of IdaB and DNA polymerase III is further stimulated by DNA synthesis, indicating close linkage between initiator inactivation and replication. In vivo, DnaA predominantly takes on the ADP form in a beta subunit-dependent manner. Thus, the initiator is negatively regulated by action of the replicase, a mechanism that may be key to effective control of the replication cycle.
Katayama
T
T
Department of Microbiology, Kyushu University Faculty of Pharmaceutical Sciences, Fukuoka, Japan.
Kubota
T
T
Kurokawa
K
K
Crooke
E
E
Sekimizu
K
K
D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002474:Cell-Free System / Q000378:metabolism; D002876:Chromosomes, Bacterial / Q000378:metabolism*; D004258:DNA Polymerase III / Q000378:metabolism*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli; D008957:Models, Genetic; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D018741:Replication Origin; D017421:Sequence Analysis
D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D018809:Proliferating Cell Nuclear Antigen; D000255:Adenosine Triphosphate; D004258:DNA Polymerase III