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Open data
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Basic information
Entry | Database: PDB / ID: 5bk4 | ||||||
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Title | Cryo-EM structure of Mcm2-7 double hexamer on dsDNA | ||||||
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![]() | HYDROLASE/DNA / complex / DNA replication / HYDROLASE-DNA complex | ||||||
Function / homology | ![]() 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 / 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 / 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 | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.9 Å | ||||||
![]() | Li, H. / Yuan, Z. / Bai, L. | ||||||
Funding support | ![]()
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![]() | ![]() 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 |
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Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 1.4 MB | Display | ![]() |
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PDB format | ![]() | 1.1 MB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 9400MC M: map data used to model this data C: citing same article ( |
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Similar structure data |
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Links
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Assembly
Deposited unit | ![]()
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Components
-DNA replication licensing factor ... , 6 types, 12 molecules 2A3B4C5D6E7F
#1: Protein | Mass: 98911.539 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: MCM2, YBL023C, YBL0438 / Production host: ![]() ![]() #2: Protein | Mass: 107653.508 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: MCM3, YEL032W, SYGP-ORF23 / Production host: ![]() ![]() #3: Protein | Mass: 105138.375 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: MCM4, CDC54, HCD21, YPR019W, YP9531.13 / Production host: ![]() ![]() #4: Protein | Mass: 86505.734 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: MCM5, CDC46, YLR274W, L9328.1 / Production host: ![]() ![]() #5: Protein | Mass: 113110.211 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: MCM6, YGL201C / Production host: ![]() ![]() #6: Protein | Mass: 95049.875 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: MCM7, CDC47, YBR202W, YBR1441 / Production host: ![]() ![]() |
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-DNA (60-mer), strand ... , 2 types, 2 molecules SO
#7: DNA chain | Mass: 18491.848 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) ![]() ![]() |
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#8: DNA chain | Mass: 18491.848 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) ![]() ![]() |
-Non-polymers , 1 types, 8 molecules ![](data/chem/img/ADP.gif)
#9: Chemical | ChemComp-ADP / |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
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Source (natural) |
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Source (recombinant) | Organism: ![]() ![]() | ||||||||||||||||||||||||
Buffer solution | pH: 8 | ||||||||||||||||||||||||
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | ||||||||||||||||||||||||
Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD |
Image recording | Electron dose: 10 e/Å2 / Film or detector model: GATAN K2 SUMMIT (4k x 4k) |
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Processing
Software | Name: PHENIX / Version: 1.11.1_2575: / Classification: refinement | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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EM software |
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CTF correction | Type: NONE | ||||||||||||||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 3.9 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 58772 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Refine LS restraints |
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