The interaction of DiaA and DnaA regulates the replication cycle in E. coli by directly promoting ATP-DnaA-specific initiation complexes

Kenji Keyamura, Norie Fujikawa, Takuma Ishida, Shogo Ozaki, Masayuki Su'etsugu, Kazuyuki Fujimitsu, Wataru Kagawa, Shigeyuki Yokoyama, Hitoshi Kurumizaka, Tsutomu Katayama

    Research output: Contribution to journalArticlepeer-review

    94 Citations (Scopus)

    Abstract

    Escherichia coli DiaA is a DnaA-binding protein that is required for the timely initiation of chromosomal replication during the cell cycle. In this study, we determined the crystal structure of DiaA at 1.8 Å resolution. DiaA forms a homotetramer consisting of a symmetrical pair of homodimers. Mutational analysis revealed that the DnaA-binding activity and formation of homotetramers are required for the stimulation of initiation by DiaA. DiaA tetramers can bind multiple DnaA molecules simultaneously. DiaA stimulated the assembly of multiple DnaA molecules on oriC, conformational changes in ATP-DnaA-specific initiation complexes, and unwinding of oriC duplex DNA. The mutant DiaA proteins are defective in these stimulations. DiaA associated also with ADP-DnaA, and stimulated the assembly of inactive ADP-DnaA-oriC complexes. Specific residues in the putative phosphosugar-binding motif of DiaA were required for the stimulation of initiation and formation of ATP-DnaA-specific- oriC complexes. Our data indicate that DiaA regulates initiation by a novel mechanism, in which DiaA tetramers most likely bind to multiple DnaA molecules and stimulate the assembly of specific ATP-DnaA-oriC complexes. These results suggest an essential role for DiaA in the promotion of replication initiation in a cell cycle coordinated manner.

    Original languageEnglish
    Pages (from-to)2083-2099
    Number of pages17
    JournalGenes and Development
    Volume21
    Issue number16
    DOIs
    Publication statusPublished - 2007 Aug 15

    Keywords

    • Cell cycle regulation
    • Complex structure
    • DNA dynamics
    • Initiation of replication
    • Initiator regulation
    • Protein complex

    ASJC Scopus subject areas

    • Genetics
    • Developmental Biology

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