+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-9400 | |||||||||
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Title | Cryo-EM structure of Mcm2-7 double hexamer on dsDNA | |||||||||
Map data | Mcm2-7 double hexamer on dsDNA | |||||||||
Sample |
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Keywords | complex / DNA replication / HYDROLASE-DNA complex | |||||||||
Function / homology | Function and homology information MCM core complex / Assembly of the pre-replicative complex / Switching of origins to a post-replicative state / MCM complex binding / nuclear DNA replication / 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 ...MCM core complex / Assembly of the pre-replicative complex / Switching of origins to a post-replicative state / MCM complex binding / nuclear DNA replication / 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 / DNA replication preinitiation complex / MCM complex / replication fork protection complex / double-strand break repair via break-induced replication / mitotic DNA replication initiation / single-stranded DNA helicase activity / regulation of DNA-templated DNA replication initiation / DNA strand elongation involved in DNA replication / silent mating-type cassette heterochromatin formation / 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 / 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 | Saccharomyces cerevisiae (brewer's yeast) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.9 Å | |||||||||
Authors | Li H / Yuan Z | |||||||||
Funding support | United States, 1 items
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Citation | Journal: Proc Natl Acad Sci U S A / Year: 2017 Title: Cryo-EM structure of Mcm2-7 double hexamer on DNA suggests a lagging-strand DNA extrusion model. Authors: Yasunori Noguchi / Zuanning Yuan / Lin Bai / Sarah Schneider / Gongpu Zhao / Bruce Stillman / Christian Speck / Huilin Li / Abstract: During replication initiation, the core component of the helicase-the Mcm2-7 hexamer-is loaded on origin DNA as a double hexamer (DH). The two ring-shaped hexamers are staggered, leading to a kinked ...During replication initiation, the core component of the helicase-the Mcm2-7 hexamer-is loaded on origin DNA as a double hexamer (DH). The two ring-shaped hexamers are staggered, leading to a kinked axial channel. How the origin DNA interacts with the axial channel is not understood, but the interaction could provide key insights into Mcm2-7 function and regulation. Here, we report the cryo-EM structure of the Mcm2-7 DH on dsDNA and show that the DNA is zigzagged inside the central channel. Several of the Mcm subunit DNA-binding loops, such as the oligosaccharide-oligonucleotide loops, helix 2 insertion loops, and presensor 1 (PS1) loops, are well defined, and many of them interact extensively with the DNA. The PS1 loops of Mcm 3, 4, 6, and 7, but not 2 and 5, engage the lagging strand with an approximate step size of one base per subunit. Staggered coupling of the two opposing hexamers positions the DNA right in front of the two Mcm2-Mcm5 gates, with each strand being pressed against one gate. The architecture suggests that lagging-strand extrusion initiates in the middle of the DH that is composed of the zinc finger domains of both hexamers. To convert the Mcm2-7 DH structure into the Mcm2-7 hexamer structure found in the active helicase, the N-tier ring of the Mcm2-7 hexamer in the DH-dsDNA needs to tilt and shift laterally. We suggest that these N-tier ring movements cause the DNA strand separation and lagging-strand extrusion. | |||||||||
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_9400.map.gz | 9.8 MB | EMDB map data format | |
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Header (meta data) | emd-9400-v30.xml emd-9400.xml | 24.8 KB 24.8 KB | Display Display | EMDB header |
Images | emd_9400.png | 175.8 KB | ||
Filedesc metadata | emd-9400.cif.gz | 9.1 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-9400 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-9400 | HTTPS FTP |
-Validation report
Summary document | emd_9400_validation.pdf.gz | 450.2 KB | Display | EMDB validaton report |
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Full document | emd_9400_full_validation.pdf.gz | 449.7 KB | Display | |
Data in XML | emd_9400_validation.xml.gz | 6 KB | Display | |
Data in CIF | emd_9400_validation.cif.gz | 6.9 KB | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-9400 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-9400 | HTTPS FTP |
-Related structure data
Related structure data | 5bk4MC M: atomic model generated by this map C: citing same article (ref.) |
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Similar 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_9400.map.gz / Format: CCP4 / Size: 64 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Annotation | Mcm2-7 double hexamer on dsDNA | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.088 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 : Mcm double hexamer bound to double-stranded DNA
+Supramolecule #1: Mcm double hexamer bound to double-stranded DNA
+Supramolecule #2: Mcm double hexamer
+Supramolecule #3: synthetic double-stranded DNA
+Macromolecule #1: DNA replication licensing factor MCM2
+Macromolecule #2: DNA replication licensing factor MCM3
+Macromolecule #3: DNA replication licensing factor MCM4
+Macromolecule #4: DNA replication licensing factor MCM5
+Macromolecule #5: DNA replication licensing factor MCM6
+Macromolecule #6: DNA replication licensing factor MCM7
+Macromolecule #7: DNA (60-mer), strand 1
+Macromolecule #8: DNA (60-mer), strand 2
+Macromolecule #9: ADENOSINE-5'-DIPHOSPHATE
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Buffer | pH: 8 |
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Vitrification | Cryogen name: ETHANE |
-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: FIELD EMISSION GUN |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |
-Image processing
Startup model | Type of model: PDB ENTRY PDB model - PDB ID: |
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Final reconstruction | Resolution.type: BY AUTHOR / Resolution: 3.9 Å / Resolution method: FSC 0.143 CUT-OFF / Software - Name: RELION (ver. 2) / Number images used: 58772 |
Initial angle assignment | Type: ANGULAR RECONSTITUTION / Software - Name: RELION (ver. 2) |
Final angle assignment | Type: ANGULAR RECONSTITUTION / Software - Name: RELION (ver. 2) |