Cryo-EM structure and dynamics of eukaryotic DNA polymerase δ holoenzyme
Cryo-EM structure and dynamics of eukaryotic DNA polymerase δ holoenzyme
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DOI：
10.1038/s41594-019-0305-z
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发表时间：
2019-10-01
影响因子：
16.8
通讯作者：
Aggarwal，Aneel K.
中科院分区：
文献类型：
--
作者：
Jain，Rinku;Rice，William J.;Aggarwal，Aneel K.
DNA聚合酶δ（Polδ）在真核生物DNA复制和修复过程中起着重要作用。Polδ在酵母和人类中是保守的，并且人类Polδ中的突变与多种癌症有关。酵母菌Pol δ由催化Pol 3和调节Pol 31和Pol 32亚基组成。本文报道了酵母Polδ全酶在DNA合成过程中的近原子分辨率（3.2 μ m）冷冻电镜结构。该结构揭示了一种意想不到的排列，其中调节亚基（Pol 31和Pol 32）位于Pol 3的核酸外切酶结构域旁边，但不与DNA接合。Pol 3的C-末端结构域包含一个4Fe−4S簇，并成为Polδ组装的基石。我们还表明，催化和调节亚基旋转相对于彼此，这是一个内在的功能的Polδ架构。总的来说，该结构为理解复制叉处的DNA事务提供了一个框架。
DNA polymerase δ (Polδ) plays pivotal roles in eukaryotic DNA replication and repair. Polδ is conserved from yeast to humans, and mutations in human Polδ have been implicated in various cancers.Saccharomyces cerevisiaePolδ consists of catalytic Pol3 and the regulatory Pol31 and Pol32 subunits. Here, we present the near atomic resolution (3.2 Å) cryo-EM structure of yeast Polδ holoenzyme in the act of DNA synthesis. The structure reveals an unexpected arrangement in which the regulatory subunits (Pol31 and Pol32) lie next to the exonuclease domain of Pol3 but do not engage the DNA. The Pol3 C-terminal domain contains a 4Fe−4S cluster and emerges as the keystone of Polδ assembly. We also show that the catalytic and regulatory subunits rotate relative to each other and that this is an intrinsic feature of the Polδ architecture. Collectively, the structure provides a framework for understanding DNA transactions at the replication fork.