We report in this paper that the amino acid residues Ile-26 and Leu-40 of the DnaA protein are essential for the DNA replication activity in vitro. Lines of evidence to support this conclusion are as follows. Variants of the DnaA protein containing either an Ile-26-Ser or Leu-40-Ser replacement were unable to support oriC DNA replication in vitro. Though the mutant DnaA proteins retained the capability to bind oriC DNA, they were unable to open the duplex DNA at oriC. Based on these and other results, we conclude that the N-terminal region of the DnaA, protein is involved in the oligomerization of this protein, an essential step for the duplex opening activity at oriC.
ASJC Scopus subject areas
- Molecular Biology