Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA.
Curr Opin Chem Biol. 2011 Oct;15(5):606-13. doi: 10.1016/j.cbpa.2011.07.016. Epub 2011 Aug 18.
To initiate DNA replication, DnaA recognizes and binds to specific sequences within the Escherichia coli chromosomal origin (oriC), and then unwinds a region within oriC. Next, DnaA interacts with DnaB helicase in loading the DnaB-DnaC complex on each separated strand. Primer formation by primase (DnaG) induces the dissociation of DnaC from DnaB, which involves the hydrolysis of ATP bound to DnaC. Recent evidence indicates that DnaC acts as a checkpoint in the transition from initiation to the elongation stage of DNA replication. Freed from DnaC, DnaB helicase unwinds the parental duplex DNA while interacting the cellular replicase, DNA polymerase III holoenzyme, and primase as it intermittently forms primers that are extended by the replicase in duplicating the chromosome.
为了启动 DNA 复制，DnaA 识别并结合大肠杆菌染色体起始点（oriC）内的特定序列，然后解开 oriC 内的一个区域。接下来，DnaA 与 DnaB 解旋酶相互作用，将 DnaB-DnaC 复合物加载到每个分离的链上。引物形成酶（DnaG）引发 DnaC 从 DnaB 上解离，这涉及到与 DnaC 结合的 ATP 的水解。最近的证据表明，DnaC 在从起始到 DNA 复制延伸阶段的转变中起检查点作用。从 DnaC 上释放出来后，DnaB 解旋酶解开亲本双链 DNA，同时与细胞复制酶、DNA 聚合酶 III 全酶和引物酶相互作用，形成引物，复制酶在复制染色体时延伸引物。
