Identification of functional domains of the Escherichia coli SeqA protein

Norie Fujikawa, Hitoshi Kurumizaka, Mitsuyoshi Yamazoe, Sota Hiraga, Shigeyuki Yokoyama*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The Escherichia coli SeqA protein, a negative regulator of chromosomal DNA replication, prevents the overinitiation of replication within one cell cycle by binding to hemimethylated G-mA-T-C sequences in the replication origin, oriC. In addition to the hemimethylated DNA-binding activity, the SeqA protein has a self-association activity, which is also considered to be essential for its regulatory function in replication initiation. To study the functional domains responsible for the DNA-binding and self-association activities, we performed a deletion analysis of the SeqA protein and found that the N-terminal (amino acid residues 1-59) and the C-terminal (amino acid residues 71-181) regions form structurally distinct domains. The N-terminal domain, which is not involved in DNA binding, has the self-association activity. In contrast, the C-terminal domain, which lacks the self-association activity, specifically binds to the hemimethylated G-mA-T-C sequence. Therefore, two essential SeqA activities, self-association and DNA-binding, are independently performed by the structurally distinct N-terminal and C-terminal domains, respectively.

Original languageEnglish
Pages (from-to)699-705
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number3
Publication statusPublished - 2003 Jan 17
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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