Indiani Chiara, McInerney Peter, Georgescu Roxana, Goodman Myron F, O'Donnell Mike
Laboratory of DNA Replication, The Rockefeller University, 1230 York Avenue, New York, New York 10021, USA.
Mol Cell. 2005 Sep 16;19(6):805-15. doi: 10.1016/j.molcel.2005.08.011.
This report demonstrates that the beta sliding clamp of E. coli binds two different DNA polymerases at the same time. One is the high-fidelity Pol III chromosomal replicase and the other is Pol IV, a low-fidelity lesion bypass Y family polymerase. Further, polymerase switching on the primed template junction is regulated in a fashion that limits the action of the low-fidelity Pol IV. Under conditions that cause Pol III to stall on DNA, Pol IV takes control of the primed template. After the stall is relieved, Pol III rapidly regains control of the primed template junction from Pol IV and retains it while it is moving, becoming resistant to further Pol IV takeover events. These polymerase dynamics within the beta toolbelt complex restrict the action of the error-prone Pol IV to only the area on DNA where it is required.
本报告表明，大肠杆菌的β滑动夹可同时结合两种不同的DNA聚合酶。一种是高保真的Pol III染色体复制酶，另一种是Pol IV，一种低保真的损伤旁路Y家族聚合酶。此外，在引发模板连接处的聚合酶切换受到调控，限制了低保真的Pol IV的作用。在导致Pol III在DNA上停滞的条件下，Pol IV控制引发模板。停滞解除后，Pol III迅速从Pol IV重新获得对引发模板连接处的控制，并在移动时保持控制，从而抵抗进一步的Pol IV接管事件。β工具带复合物内的这些聚合酶动态变化将易出错的Pol IV的作用限制在DNA上仅需要它的区域。
