2012年2月
Highly organized DnaA-oriC complexes recruit the single-stranded DNA for replication initiation
NUCLEIC ACIDS RESEARCH
- ,
- 巻
- 40
- 号
- 4
- 開始ページ
- 1648
- 終了ページ
- 1665
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1093/nar/gkr832
- 出版者・発行元
- OXFORD UNIV PRESS
In Escherichia coli, the replication origin oriC consists of two functional regions: the duplex unwinding element (DUE) and its flanking DnaA-assembly region (DAR). ATP-DnaA molecules multimerize on DAR, unwinding DUE for DnaB helicase loading. However, DUE-unwinding mechanisms and functional structures in DnaA-oriC complexes supporting those remain unclear. Here, using various in vitro reconstituted systems, we identify functionally distinct DnaA sub-complexes formed on DAR and reveal novel mechanisms in DUE unwinding. The DUE-flanking left-half DAR carrying high-affinity DnaA box R1 and the ATP-DnaA-preferential DnaA box R5, tau 1-2 and I1-2 sites formed a DnaA sub-complex competent in DUE unwinding and ssDUE binding, thereby supporting basal DnaB loading activity. This sub-complex is further subdivided into two; the DUE-distal DnaA sub-complex formed on the ATP-DnaA-preferential sites binds ssDUE. Notably, the DUE-flanking, DnaA box R1-DnaA sub-complex recruits DUE to the DUE-distal DnaA sub-complex in concert with a DNA-bending nucleoid protein IHF, thereby promoting DUE unwinding and binding of ssDUE. The right-half DAR-DnaA sub-complex stimulated DnaB loading, consistent with in vivo analyses. Similar features are seen in DUE unwinding of the hyperthermophile, Thermotoga maritima, indicating evolutional conservation of those mechanisms.
- リンク情報
- ID情報
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- DOI : 10.1093/nar/gkr832
- ISSN : 0305-1048
- PubMed ID : 22053082
- Web of Science ID : WOS:000301069400027