DiaA dynamics are coupled with changes in initial origin complexes leading to helicase loading

Kenji Keyamura, Yoshito Abe, Masahiro Higashi, Tadashi Ueda, Tsutomu Katayama

研究成果: ジャーナルへの寄稿学術誌査読

64 被引用数 (Scopus)


Chromosomal replication initiation requires the regulated formation of dynamic higher order complexes. Escherichia coli ATP-DnaA forms a specific multimer on oriC, resulting inDNA unwinding and DnaB helicase loading. DiaA, a DnaA-binding protein, directly stimulates the formation of ATP-DnaA multimers on oriC and ensures timely replication initiation. In this study, DnaA Phe-46 was identified as the crucial DiaA-binding site required for DiaA-stimulated ATP-DnaA assembly on oriC. Moreover, we show that DiaA stimulation requires only a subgroup of DnaA molecules binding to oriC, that DnaA Phe-46 is also important in the loading of DnaB helicase onto the oriC-DnaA complexes, and that this process also requires only a subgroup of DnaA molecules. Despite the use of only a DnaA subgroup, DiaA inhibited DnaB loading on oriC-DnaA complexes, suggesting that DiaA and DnaB bind to a common DnaA subgroup. A cellular factor can relieve the DiaA inhibition, allowing DnaB loading. Consistently, DnaA F46A caused retarded initiations in vivo in a DiaA-independent manner. It is therefore likely that DiaA dynamics are crucial in the regulated sequential progress of DnaA assembly and DnaB loading. We accordingly propose a model for dynamic structural changes of initial oriC complexes loading DiaA or DnaB helicase.

ジャーナルJournal of Biological Chemistry
出版ステータス出版済み - 9月 11 2009

!!!All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学


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