The mechanism of eukaryotic CMG helicase activation
نویسندگان
چکیده
منابع مشابه
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 unexpecte...
متن کاملStructure of the eukaryotic replicative CMG helicase suggests a pumpjack motion for translocation
In eukaryotes, two Mcm2–7 rings are loaded onto DNA at origins of replication during G1 phase1,2. The double hexamer is inactive as a heli case but is activated upon entry into S phase by the Dbf4dependent Cdc7 kinase, cyclindependent kinase and several transient factors that activate origins; subsequently, Cdc45 and GINS assemble onto each Mcm2–7 complex, thereby forming two active CMG heli...
متن کاملDNA binding polarity, dimerization, and ATPase ring remodeling in the CMG helicase of the eukaryotic replisome
The Cdc45/Mcm2-7/GINS (CMG) helicase separates DNA strands during replication in eukaryotes. How the CMG is assembled and engages DNA substrates remains unclear. Using electron microscopy, we have determined the structure of the CMG in the presence of ATPγS and a DNA duplex bearing a 3' single-stranded tail. The structure shows that the MCM subunits of the CMG bind preferentially to single-stra...
متن کاملIsolation of the Cdc45/Mcm2-7/GINS (CMG) complex, a candidate for the eukaryotic DNA replication fork helicase.
The protein Cdc45 plays a critical but poorly understood role in the initiation and elongation stages of eukaryotic DNA replication. To study Cdc45's function in DNA replication, we purified Cdc45 protein from Drosophila embryo extracts by a combination of traditional and immunoaffinity chromatography steps and found that the protein exists in a stable, high-molecular-weight complex with the Mc...
متن کاملAction of CMG with strand-specific DNA blocks supports an internal unwinding mode for the eukaryotic replicative helicase
Replicative helicases are ring-shaped hexamers that encircle DNA for duplex unwinding. The currently accepted view of hexameric helicase function is by steric exclusion, where the helicase encircles one DNA strand and excludes the other, acting as a wedge with an external DNA unwinding point during translocation. Accordingly, strand-specific blocks only affect these helicases when placed on the...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nature
سال: 2018
ISSN: 0028-0836,1476-4687
DOI: 10.1038/nature25787