3D architecture of DNA Pol α reveals the functional core of multi‐subunit replicative polymerases

作者：Sebastian Klinge, Rafael Núñez‐Ramírez, Óscar Llorca, Luca Pellegrini · 发表于：The EMBO Journal · 年份：2009 · DOI：10.1038/emboj.2009.150 · 被引用次数：112 · 研究领域：DNA Repair Mechanisms、Genomics and Chromatin Dynamics、Bacterial Genetics and Biotechnology

Eukaryotic DNA replication requires the coordinated activity of the multi-subunit DNA polymerases: Pol alpha, Pol delta and Pol epsilon. The conserved catalytic and regulatory B subunits associate in a constitutive heterodimer that represents the functional core of all three replicative polymerases. Here, we combine X-ray crystallography and electron microscopy (EM) to describe subunit interaction and 3D architecture of heterodimeric yeast Pol alpha. The crystal structure of the C-terminal domain (CTD) of the catalytic subunit bound to the B subunit illustrates a conserved mechanism of accessory factor recruitment by replicative polymerases. The EM reconstructions of Pol alpha reveal a bilobal shape with separate catalytic and regulatory modules. Docking of the B-CTD complex in the EM reconstruction shows that the B subunit is tethered to the polymerase domain through a structured but flexible linker. Our combined findings provide a structural template for the common functional architecture of the three major replicative DNA polymerases.