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- EMDB-8519: Structure of Eukaryotic CMG Helicase at a Replication Fork and Im... -
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Open data
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Basic information
Entry | Database: EMDB / ID: EMD-8519 | |||||||||
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Title | Structure of Eukaryotic CMG Helicase at a Replication Fork and Implications | |||||||||
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Function / homology | ![]() Unwinding of DNA / MCM core complex / Assembly of the pre-replicative complex / Switching of origins to a post-replicative state / MCM complex binding / GINS complex / DNA strand elongation involved in mitotic DNA replication / nuclear DNA replication / mitotic DNA replication preinitiation complex assembly / premeiotic DNA replication ...Unwinding of DNA / MCM core complex / Assembly of the pre-replicative complex / Switching of origins to a post-replicative state / MCM complex binding / GINS complex / DNA strand elongation involved in mitotic DNA replication / nuclear DNA replication / 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 / MCM complex / Activation of ATR in response to replication stress / DNA replication preinitiation complex / replication fork protection complex / double-strand break repair via break-induced replication / mitotic DNA replication initiation / single-stranded DNA helicase activity / 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 / DNA replication initiation / subtelomeric heterochromatin formation / DNA helicase activity / helicase activity / transcription elongation by RNA polymerase II / heterochromatin formation / DNA-templated DNA replication / single-stranded DNA binding / DNA helicase / chromosome, telomeric region / DNA damage response / chromatin binding / ATP hydrolysis activity / nucleoplasm / ATP binding / nucleus / metal ion binding / cytoplasm Similarity search - Function | |||||||||
Biological species | ![]() ![]() ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 4.9 Å | |||||||||
![]() | Li B / Georgescu R / Yuan Z / Santos R / Sun J / Zhang D / Yurieva O / Li H / O'Donnell ME | |||||||||
Funding support | ![]()
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![]() | ![]() 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 |
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Structure viewer | EM map: ![]() ![]() ![]() |
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 59.7 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 29.5 KB 29.5 KB | Display Display | ![]() |
Images | ![]() | 86.4 KB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 5u8tMC ![]() 8518C ![]() 8520C ![]() 5u8sC M: atomic model generated by this map C: citing same article ( |
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Similar structure data |
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
File | ![]() | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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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
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Sample components
+Entire : CMG-ssDNA
+Supramolecule #1: CMG-ssDNA
+Macromolecule #1: DNA replication licensing factor MCM2
+Macromolecule #2: DNA replication licensing factor MCM3
+Macromolecule #3: DNA replication licensing factor MCM4
+Macromolecule #4: Minichromosome maintenance protein 5
+Macromolecule #5: DNA replication licensing factor MCM6
+Macromolecule #6: DNA replication licensing factor MCM7
+Macromolecule #7: DNA replication complex GINS protein PSF1
+Macromolecule #8: DNA replication complex GINS protein PSF2
+Macromolecule #9: DNA replication complex GINS protein PSF3
+Macromolecule #10: DNA replication complex GINS protein SLD5
+Macromolecule #11: Cell division control protein 45
+Macromolecule #12: DNA (5'-D(P*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*T)-3')
+Macromolecule #13: PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 7.5 |
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Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Average electron dose: 10.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
Startup model | Type of model: OTHER / Details: EMD-6535 |
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Final reconstruction | Applied symmetry - Point group: C1 (asymmetric) / Resolution.type: BY AUTHOR / Resolution: 4.9 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 395443 |
Initial angle assignment | Type: PROJECTION MATCHING |
Final angle assignment | Type: PROJECTION MATCHING |
-Atomic model buiding 1
Refinement | Space: REAL / Protocol: RIGID BODY FIT |
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Output model | ![]() PDB-5u8t: |