Mima S, Yamagachi Y, Kondo T, Tsuchiya T, Mizushima T
Faculty of Pharmaceutical Sciences, Okayama University, Japan.
FEMS Microbiol Lett. 1999 Jul 1;176(1):163-7. doi: 10.1111/j.1574-6968.1999.tb13657.x.
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.
我们在本文中报告，DnaA蛋白的氨基酸残基Ile-26和Leu-40对于体外DNA复制活性至关重要。支持这一结论的证据如下。含有Ile-26-Ser或Leu-40-Ser替代的DnaA蛋白变体在体外无法支持oriC DNA复制。尽管突变的DnaA蛋白保留了结合oriC DNA的能力，但它们无法在oriC处打开双链DNA。基于这些及其他结果，我们得出结论，DnaA蛋白的N端区域参与了该蛋白的寡聚化，这是oriC处双链打开活性的关键步骤。
