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

• Sebastian Klinge ^[1] ; Rafael Núñez-Ramírez ^[2] ; Oscar Llorca ^[2] ; Luca Pellegrini ^[1]
  1. [1] University of Cambridge

     University of Cambridge

     Cambridge District, Reino Unido

     
  2. [2] Consejo Superior de Investigaciones Científicas

     Consejo Superior de Investigaciones Científicas

     Madrid, España

     
• Localización: EMBO journal: European Molecular Biology Organization, ISSN 0261-4189, Vol. 28, Nº. 13, 2009, págs. 1978-1987
• Idioma: inglés
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• Resumen

  • Eukaryotic DNA replication requires the coordinated activity of the multi-subunit DNA polymerases: Pol α, Pol δ and Pol ɛ. 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 α. 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 α 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.