The eukaryotic CMG helicase pumpjack and integration into the replisome.
The eukaryotic replisome is α multiprotein machine that contains DNA polymerases, sliding clamps, helicase, and primase along with several factors that participate in cell cycle and checkpoint control. The detailed structure of the 11-subunit CMG helicase (Cdc45/Mcm2-7/GINS) has been solved recently by cryoEM single-particle 3D reconstruction and reveals pumpjack motions that imply an unexpected mechanism of DNA translocation. CMG is also the organizing center of the replisome. Recent in vitro reconstitution of leading and lagging strand DNA synthesis has enabled structural analysis of the replisome. By building the replisome in stages from pure proteins, single-particle EM studies have identified the overall architecture of the eukaryotic replisome. Suprisingly leading and lagging strand polymerases bind to opposite faces of the CMG helicase, unlike the long-held view that DNA polymerases are located in back of the helicase to act on the unwound strands.
a Biology Department , Brookhaven National Laboratory , Upton , NY , USA.
Jingchuan
J
Sun
b Department of Biochemistry & Cell Biology , Stony Brook University , Stony Brook , NY , USA.
Zuanning
Z
Yuan
c Howard Hughes Medical Institute and the DNA Replication Laboratory , The Rockefeller University , New York , NY , USA.
Roxanna
R
Georgescu
a Biology Department , Brookhaven National Laboratory , Upton , NY , USA.|b Department of Biochemistry & Cell Biology , Stony Brook University , Stony Brook , NY , USA.
Huilin
H
Li
c Howard Hughes Medical Institute and the DNA Replication Laboratory , The Rockefeller University , New York , NY , USA.
Mike
M
O'Donnell
D000818:Animals; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism*; D004261:DNA Replication; D056890:Eukaryota / Q000201:enzymology* / Q000235:genetics*; D006801:Humans
D004247:DNA; D004265:DNA Helicases
3D reconstruction; CMG; DNA helicase; DNA polymerase; cryoelectron microscopy; primase; replication fork; replisome