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Yorodumi- EMDB-8520: Structure of Eukaryotic CMG Helicase at a Replication Fork and Im... -
+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-8520 | |||||||||
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Title | Structure of Eukaryotic CMG Helicase at a Replication Fork and Implications to Replisome Architecture and Origin Initiation | |||||||||
Map data | Eukaryotic CMG Helicase at a Replication Fork | |||||||||
Sample |
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Function / homology | Function and homology information Unwinding of DNA / DNA strand elongation involved in mitotic DNA replication / MCM core complex / Assembly of the pre-replicative complex / Switching of origins to a post-replicative state / nuclear DNA replication / MCM complex binding / GINS complex / mitotic DNA replication preinitiation complex assembly / premeiotic DNA replication ...Unwinding of DNA / DNA strand elongation involved in mitotic DNA replication / MCM core complex / Assembly of the pre-replicative complex / Switching of origins to a post-replicative state / nuclear DNA replication / MCM complex binding / GINS complex / mitotic DNA replication preinitiation complex assembly / premeiotic DNA replication / pre-replicative complex assembly involved in nuclear cell cycle DNA replication / mitotic DNA replication / Activation of the pre-replicative complex / CMG complex / nuclear pre-replicative complex / Activation of ATR in response to replication stress / MCM complex / DNA replication preinitiation complex / double-strand break repair via break-induced replication / single-stranded DNA helicase activity / replication fork protection complex / mitotic DNA replication initiation / silent mating-type cassette heterochromatin formation / regulation of DNA-templated DNA replication initiation / DNA strand elongation involved in DNA replication / DNA unwinding involved in DNA replication / nuclear replication fork / DNA replication origin binding / subtelomeric heterochromatin formation / DNA replication initiation / heterochromatin formation / DNA helicase activity / helicase activity / DNA-templated DNA replication / single-stranded DNA binding / DNA helicase / chromosome, telomeric region / DNA damage response / chromatin binding / ATP hydrolysis activity / nucleoplasm / ATP binding / metal ion binding / nucleus / cytoplasm Similarity search - Function | |||||||||
Biological species | Saccharomyces cerevisiae (brewer's yeast) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 6.2 Å | |||||||||
Authors | Georgescu R / Yuan Z / Bai L / Santos R / Sun J / Zhang D / Yurieva O / Li H / O'Donnell M | |||||||||
Funding support | United States, 2 items
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Citation | Journal: Proc Natl Acad Sci U S A / Year: 2017 Title: Structure of eukaryotic CMG helicase at a replication fork and implications to replisome architecture and origin initiation. Authors: Roxana Georgescu / Zuanning Yuan / Lin Bai / Ruda de Luna Almeida Santos / Jingchuan Sun / Dan Zhang / Olga Yurieva / Huilin Li / Michael E O'Donnell / Abstract: The eukaryotic CMG (Cdc45, Mcm2-7, GINS) helicase consists of the Mcm2-7 hexameric ring along with five accessory factors. The Mcm2-7 heterohexamer, like other hexameric helicases, is shaped like a ...The eukaryotic CMG (Cdc45, Mcm2-7, GINS) helicase consists of the Mcm2-7 hexameric ring along with five accessory factors. The Mcm2-7 heterohexamer, like other hexameric helicases, is shaped like a ring with two tiers, an N-tier ring composed of the N-terminal domains, and a C-tier of C-terminal domains; the C-tier contains the motor. In principle, either tier could translocate ahead of the other during movement on DNA. We have used cryo-EM single-particle 3D reconstruction to solve the structure of CMG in complex with a DNA fork. The duplex stem penetrates into the central channel of the N-tier and the unwound leading single-strand DNA traverses the channel through the N-tier into the C-tier motor, 5'-3' through CMG. Therefore, the N-tier ring is pushed ahead by the C-tier ring during CMG translocation, opposite the currently accepted polarity. The polarity of the N-tier ahead of the C-tier places the leading Pol ε below CMG and Pol α-primase at the top of CMG at the replication fork. Surprisingly, the new N-tier to C-tier polarity of translocation reveals an unforeseen quality-control mechanism at the origin. Thus, upon assembly of head-to-head CMGs that encircle double-stranded DNA at the origin, the two CMGs must pass one another to leave the origin and both must remodel onto opposite strands of single-stranded DNA to do so. We propose that head-to-head motors may generate energy that underlies initial melting at the origin. | |||||||||
History |
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-Structure visualization
Movie |
Movie viewer |
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Structure viewer | EM map: SurfViewMolmilJmol/JSmol |
Supplemental images |
-Downloads & links
-EMDB archive
Map data | emd_8520.map.gz | 59.6 MB | EMDB map data format | |
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Header (meta data) | emd-8520-v30.xml emd-8520.xml | 8.6 KB 8.6 KB | Display Display | EMDB header |
Images | emd_8520.png | 73.7 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-8520 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-8520 | HTTPS FTP |
-Related structure data
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Related items in Molecule of the Month |
-Map
File | Download / File: emd_8520.map.gz / Format: CCP4 / Size: 64 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Annotation | Eukaryotic CMG Helicase at a Replication Fork | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.3 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
-Sample components
-Entire : CMG-short ssDNA (9 base)
Entire | Name: CMG-short ssDNA (9 base) |
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Components |
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-Supramolecule #1: CMG-short ssDNA (9 base)
Supramolecule | Name: CMG-short ssDNA (9 base) / type: complex / ID: 1 / Parent: 0 |
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Source (natural) | Organism: Saccharomyces cerevisiae (brewer's yeast) |
Recombinant expression | Organism: Saccharomyces cerevisiae (brewer's yeast) / Recombinant plasmid: pRS402 |
Molecular weight | Theoretical: 750 KDa |
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Buffer | pH: 7.5 |
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Vitrification | Cryogen name: ETHANE |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
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Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELDBright-field microscopy |
Image recording | Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Average electron dose: 10.0 e/Å2 |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |
-Image processing
Startup model | Type of model: OTHER / Details: EMD-6535 |
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Initial angle assignment | Type: PROJECTION MATCHING |
Final angle assignment | Type: PROJECTION MATCHING |
Final reconstruction | Applied symmetry - Point group: C1 (asymmetric) / Resolution.type: BY AUTHOR / Resolution: 6.2 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 83043 |