title: Structure of Saccharomyces cerevisiae DNA polymerase epsilon by cryo-electron microscopy.
abstract: The structure of the multisubunit yeast DNA polymerase epsilon (Pol epsilon) was determined to 20-A resolution using cryo-EM and single-particle image analysis. A globular domain comprising the catalytic Pol2 subunit is flexibly connected to an extended structure formed by subunits Dpb2, Dpb3 and Dpb4. Consistent with the reported involvement of the latter in interaction with nucleic acids, the Dpb portion of the structure directly faces a single cleft in the Pol2 subunit that seems wide enough to accommodate double-stranded DNA. Primer-extension experiments reveal that Pol epsilon processivity requires a minimum length of primer-template duplex that corresponds to the dimensions of the extended Dpb structure. Together, these observations suggest a mechanism for interaction of Pol epsilon with DNA that might explain how the structure of the enzyme contributes to its intrinsic processivity.
authors.affiliation: Department of Structural Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA. asturias@scripps.edu
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Asturias
authors.forename: Iris K
authors.initials: IK
authors.lastname: Cheung
authors.forename: Nasim
authors.initials: N
authors.lastname: Sabouri
authors.forename: Olga
authors.initials: O
authors.lastname: Chilkova
authors.forename: Daniel
authors.initials: D
authors.lastname: Wepplo
authors.forename: Erik
authors.initials: E
authors.lastname: Johansson
mesh_terms: D002384:Catalysis; D020285:Cryoelectron Microscopy; D053487:DEAD-box RNA Helicases; D004257:DNA Polymerase II / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D004271:DNA, Fungal / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D008958:Models, Molecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D020365:RNA Helicases / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D004271:DNA, Fungal; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D004257:DNA Polymerase II; C438898:Dbp2 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases