The exceptionally tight affinity of DnaA for ATP/ADP requires a unique aspartic acid residue in the AAA+ sensor 1 motif

Hironori Kawakami, Shogo Ozaki, Shigeo Suzuki, Kenta Nakamura, Takayuki Senriuchi, Masayuki Su'etsugu, Kazuyuki Fujimitsu, Tsutomu Katayama

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Escherichia coli DnaA, an AAA+ superfamily protein, initiates chromosomal replication in an ATP-binding-dependent manner. Although DnaA has conserved Walker A/B motifs, it binds adenine nucleotides 10- to 100-fold more tightly than do many other AAA+ proteins. This study shows that the DnaA Asp-269 residue, located in the sensor 1 motif, plays a specific role in supporting high-affinity ATP/ADP binding. The affinity of the DnaA D269A mutant for ATP/ADP is at least 10- to 100-fold reduced compared with that of the wild-type and DnaA R270A proteins. In contrast, the abilities of DnaA D269A to bind a typical DnaA box, unwind oriC duplex in the presence of elevated concentrations of ATP, load DnaB onto DNA and support minichromosomal replication in a reconstituted system are retained. Whereas the acidic Asp residue is highly conserved among eubacterial DnaA homologues, the corresponding residue in many other AAA+ proteins is Asn/Thr and in some AAA+ proteins these neutral residues are essential for ATP hydrolysis but not ATP binding. As the intrinsic ATPase activity of DnaA is extremely weak, this study reveals a novel and specific function for the sensor 1 motif in tight ATP/ADP binding, one that depends on the alternate key residue Asp.

Original languageEnglish
Pages (from-to)1310-1324
Number of pages15
JournalMolecular Microbiology
Volume62
Issue number5
DOIs
Publication statusPublished - Dec 1 2006

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology

Fingerprint Dive into the research topics of 'The exceptionally tight affinity of DnaA for ATP/ADP requires a unique aspartic acid residue in the AAA+ sensor 1 motif'. Together they form a unique fingerprint.

Cite this