The DnaA homolog of the hyperthermophilic eubacterium Thermotoga maritima an open complex with a minimal 149-bp origin region in an ATP-dependent manner

Shogo Ozaki, Kazuyuki Fujimitsu, Hitoshi Kurumizaka, Tsutomu Katayama

    研究成果: Article査読

    25 被引用数 (Scopus)

    抄録

    In Escherichia coli, ATP-DnaA, but not ADP-DnaA, forms an initiation complex that undergoes site-specific duplex DNA unwinding, open complex formation. However, it remains unclear how highly the ATP-dependent activation of the initiation factor is conserved in evolution. The hyperthermophile Thermotoga maritima is one of the most ancient eubacteria in evolution. Here, we show that the DnaA homolog (tmaDnaA) of this bacterium forms open complexes with the predicted origin region (tma-oriC) in vitro. Tma DnaA has a strong and specific affinity for ATP/ADP as well as for 12-mer repeating sequences within the tma-oriC. Unlike ADPtma DnaA, ATPtma DnaA ishighly cooperative in DNA binding and forms open complexes in a manner that depends on temperature and the superhelical tension of the tma-oriC-bearing plasmid. The minimal tma-oriC required for unwinding is a 149-bp region containing five repeats of the 12-mer sequence and two AT-rich 9-mer repeats. Tma DnaA-binding to the 12-mer motif provokes DNA bending. The 9-mer region is the duplex-unwinding site. The tma DnaA-binding and unwinding motifs of tma-oriC share sequence homology with corresponding archaeal and eukaryotic sequences. These findings suggest that the ATP-dependent molecular switch of the initiator and the mechanisms in the replication initiation complex are highly conserved in eubacterial evolution.

    本文言語English
    ページ(範囲)425-438
    ページ数14
    ジャーナルGenes to Cells
    11
    4
    DOI
    出版ステータスPublished - 2006 4

    ASJC Scopus subject areas

    • Genetics
    • Cell Biology

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