PDBsum entry 4c8h

DNA replication

PDB id: 4c8h

Contents

Protein chains

431 a.a.

Waters ×163

PDB id:

4c8h

Name:

DNA replication

Title:

Crystal structure of thE C-terminal region of yeast ctf4, selenomethionine protein.

Structure:

Ctf4. Chain: a, b, c. Fragment: c-terminal domain. Engineered: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932. Expressed in: escherichia coli. Expression_system_taxid: 469008. Expression_system_variant: rosetta2.

Resolution:

2.69Å R-factor: 0.191 R-free: 0.225

Authors:

A.C.Simon,L.Pellegrini

Key ref:

A.C.Simon et al. (2014). A Ctf4 trimer couples the CMG helicase to DNA polymerase α in the eukaryotic replisome. Nature, 510, 293-297. PubMed id: 24805245 DOI: 10.1038/nature13234

Date:

01-Oct-13 Release date: 30-Apr-14

Protein chains

Q01454  (CTF4_YEAST) -  DNA polymerase alpha-binding protein from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 927 a.a.

Struc: 431 a.a.

DOI no: 10.1038/nature13234

Nature 510:293-297 (2014)

PubMed id: 24805245

A Ctf4 trimer couples the CMG helicase to DNA polymerase α in the eukaryotic replisome.

A.C.Simon, J.C.Zhou, R.L.Perera, F.van Deursen, C.Evrin, M.E.Ivanova, M.L.Kilkenny, L.Renault, S.Kjaer, D.Matak-Vinković, K.Labib, A.Costa, L.Pellegrini.

ABSTRACT

Efficient duplication of the genome requires the concerted action of helicase and DNA polymerases at replication forks to avoid stalling of the replication machinery and consequent genomic instability. In eukaryotes, the physical coupling between helicase and DNA polymerases remains poorly understood. Here we define the molecular mechanism by which the yeast Ctf4 protein links the Cdc45-MCM-GINS (CMG) DNA helicase to DNA polymerase α (Pol α) within the replisome. We use X-ray crystallography and electron microscopy to show that Ctf4 self-associates in a constitutive disk-shaped trimer. Trimerization depends on a β-propeller domain in the carboxy-terminal half of the protein, which is fused to a helical extension that protrudes from one face of the trimeric disk. Critically, Pol α and the CMG helicase share a common mechanism of interaction with Ctf4. We show that the amino-terminal tails of the catalytic subunit of Pol α and the Sld5 subunit of GINS contain a conserved Ctf4-binding motif that docks onto the exposed helical extension of a Ctf4 protomer within the trimer. Accordingly, we demonstrate that one Ctf4 trimer can support binding of up to three partner proteins, including the simultaneous association with both Pol α and GINS. Our findings indicate that Ctf4 can couple two molecules of Pol α to one CMG helicase within the replisome, providing a new model for lagging-strand synthesis in eukaryotes that resembles the emerging model for the simpler replisome of Escherichia coli. The ability of Ctf4 to act as a platform for multivalent interactions illustrates a mechanism for the concurrent recruitment of factors that act together at the fork.