6HV8

Cryo-EM structure of S. cerevisiae Polymerase epsilon deltacat mutant

Summary for 6HV8

• Entry DOI: 10.2210/pdb6hv8/pdb
• EMDB information: 0287
• Descriptor: DNA polymerase epsilon subunit B, DNA polymerase epsilon catalytic subunit A, ZINC ION (3 entities in total)
• Functional Keywords: polymerase epsilon, dna replication, enzyme, dna polymerase, dna binding protein
• Biological source: Saccharomyces cerevisiae (Baker's yeast); More
• Total number of polymer chains: 2
• Total formula weight: 183524.42

Authors

Goswami, P.,Purkiss, A.,Cheung, A.,Costa, A. (deposition date: 2018-10-10, release date: 2018-12-12, Last modification date: 2024-10-16)

Primary citation

Goswami, P.,Abid Ali, F.,Douglas, M.E.,Locke, J.,Purkiss, A.,Janska, A.,Eickhoff, P.,Early, A.,Nans, A.,Cheung, A.M.C.,Diffley, J.F.X.,Costa, A.
Structure of DNA-CMG-Pol epsilon elucidates the roles of the non-catalytic polymerase modules in the eukaryotic replisome.
Nat Commun, 9:5061-5061, 2018

PubMed Abstract: Eukaryotic origin firing depends on assembly of the Cdc45-MCM-GINS (CMG) helicase. A key step is the recruitment of GINS that requires the leading-strand polymerase Pol epsilon, composed of Pol2, Dpb2, Dpb3, Dpb4. While a truncation of the catalytic N-terminal Pol2 supports cell division, Dpb2 and C-terminal Pol2 (C-Pol2) are essential for viability. Dpb2 and C-Pol2 are non-catalytic modules, shown or predicted to be related to an exonuclease and DNA polymerase, respectively. Here, we present the cryo-EM structure of the isolated C-Pol2/Dpb2 heterodimer, revealing that C-Pol2 contains a DNA polymerase fold. We also present the structure of CMG/C-Pol2/Dpb2 on a DNA fork, and find that polymerase binding changes both the helicase structure and fork-junction engagement. Inter-subunit contacts that keep the helicase-polymerase complex together explain several cellular phenotypes. At least some of these contacts are preserved during Pol epsilon-dependent CMG assembly on path to origin firing, as observed with DNA replication reconstituted in vitro.

PubMed: 30498216
DOI: 10.1038/s41467-018-07417-1

Experimental method

ELECTRON MICROSCOPY (4.4 Å)