Krause M, Rückert B, Lurz R, Messer W
Max-Planck-Institut für molekulare Genetik, Berlin-Dahlem, Germany.
J Mol Biol. 1997 Dec 5;274(3):365-80. doi: 10.1006/jmbi.1997.1404.
The initial steps in the formation of the initiation complex at oriC of Bacillus subtilis were analyzed with special emphasis on the exchangeability of B. subtilis DnaA protein by DnaA of Escherichia coli. The DNA binding domain of B. subtilis DnaA protein was localized in the 93 C-terminal amino acids. Formation of the "initial complex", as analyzed by electron microscopy, was indistinguishable with B. subtilis DnaA protein or with E. coli DnaA. Similarly, both proteins were able to form loops by interaction of DnaA proteins bound to the DnaA box regions upstream and downstream of the dnaA gene in B. subtilis oriC. The region of local unwinding in the "open complex" was precisely defined. It is located at one side of a region of helical instability, a DNA unwinding element (DUE). Unwinding in oriC could only be catalyzed by the homologous DnaA protein.
对枯草芽孢杆菌oriC处起始复合物形成的初始步骤进行了分析，特别强调了大肠杆菌DnaA蛋白对枯草芽孢杆菌DnaA蛋白的可交换性。枯草芽孢杆菌DnaA蛋白的DNA结合结构域位于C末端的93个氨基酸处。通过电子显微镜分析，“初始复合物”的形成在枯草芽孢杆菌DnaA蛋白或大肠杆菌DnaA蛋白作用下并无差异。同样，两种蛋白都能够通过与枯草芽孢杆菌oriC中dnaA基因上游和下游的DnaA框区域结合的DnaA蛋白相互作用形成环。“开放复合物”中局部解旋区域得到了精确界定。它位于螺旋不稳定区域（一种DNA解旋元件，DUE）的一侧。oriC中的解旋只能由同源DnaA蛋白催化。
