Regulatory dynamics in the ternary DnaA complex for initiation of chromosomal replication in Escherichia coli.

ABSTRACT: In Escherichia coli, the level of the ATP-DnaA initiator is increased temporarily at the time of replication initiation. The replication origin, oriC, contains a duplex-unwinding element (DUE) flanking a DnaA-oligomerization region (DOR), which includes twelve DnaA-binding sites (DnaA boxes) and the DNA-bending protein IHF-binding site (IBS). Although complexes of IHF and ATP-DnaA assembly on the DOR unwind the DUE, the configuration of the crucial nucleoprotein complexes remains elusive. To resolve this, we analyzed individual DnaA protomers in the complex and here demonstrate that the DUE-DnaA-box-R1-IBS-DnaA-box-R5M region is essential for DUE unwinding. R5M-bound ATP-DnaA predominantly promotes ATP-DnaA assembly on the DUE-proximal DOR, and R1-bound DnaA has a supporting role. This mec

SUBMITTER: Sakiyama Y 

PROVIDER: S-EPMC5716108 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature