Structure of the processive human Pol δ holoenzyme
Structure of the processive human Pol δ holoenzyme
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DOI：
10.1038/s41467-020-14898-6
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发表时间：
2020-02-28
影响因子：
16.6
通讯作者：
De Biasio，Alfredo
中科院分区：
文献类型：
--
作者：
Lancey，Claudia;Tehseen，Muhammad;De Biasio，Alfredo
在真核生物中，与增殖细胞核抗原（PCNA）结合的DNA聚合酶δ（Pol δ）复制滞后链，并与瓣状核酸内切酶1（FEN 1）合作处理冈崎片段进行连接。我们提出了高分辨率的冷冻电镜结构的人进行性Pol δ-DNA-PCNA复合物在FEN 1的存在和不存在。Pol δ通过催化亚基的C-末端结构域锚定到三个PCNA单体之一。催化核心以开放构型位于PCNA顶部，而调节亚基横向突出。这种安排允许PCNA线程和稳定的DNA退出催化裂缝和招聘FEN 1到一个未占用的单体在工具带的方式。替代全酶构象揭示了重要的功能相互作用，保持PCNA的方向在合成过程中。这项工作揭示了Pol δ复制人类基因组的结构基础。
In eukaryotes, DNA polymerase δ (Pol δ) bound to the proliferating cell nuclear antigen (PCNA) replicates the lagging strand and cooperates with flap endonuclease 1 (FEN1) to process the Okazaki fragments for their ligation. We present the high-resolution cryo-EM structure of the human processive Pol δ–DNA–PCNA complex in the absence and presence of FEN1. Pol δ is anchored to one of the three PCNA monomers through the C-terminal domain of the catalytic subunit. The catalytic core sits on top of PCNA in an open configuration while the regulatory subunits project laterally. This arrangement allows PCNA to thread and stabilize the DNA exiting the catalytic cleft and recruit FEN1 to one unoccupied monomer in a toolbelt fashion. Alternative holoenzyme conformations reveal important functional interactions that maintain PCNA orientation during synthesis. This work sheds light on the structural basis of Pol δ’s activity in replicating the human genome.