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Open data
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Basic information
Entry | Database: PDB / ID: 8gj2 | ||||||
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Title | E. coli clamp loader with closed clamp on primed template DNA | ||||||
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![]() | DNA BINDING PROTEIN/DNA / clamp loader / DNA clamp / AAA+ / ATPase / DNA BINDING PROTEIN-DNA complex | ||||||
Function / homology | ![]() DNA polymerase III, clamp loader complex / Hda-beta clamp complex / bacterial-type DNA replication / replication inhibiting complex / DNA clamp loader activity / DNA polymerase III complex / replisome / regulation of DNA-templated DNA replication initiation / DNA strand elongation involved in DNA replication / DNA polymerase processivity factor activity ...DNA polymerase III, clamp loader complex / Hda-beta clamp complex / bacterial-type DNA replication / replication inhibiting complex / DNA clamp loader activity / DNA polymerase III complex / replisome / regulation of DNA-templated DNA replication initiation / DNA strand elongation involved in DNA replication / DNA polymerase processivity factor activity / error-prone translesion synthesis / negative regulation of DNA-templated DNA replication initiation / 3'-5' exonuclease activity / ribonucleoside triphosphate phosphatase activity / response to radiation / DNA-templated DNA replication / DNA-directed DNA polymerase / DNA-directed DNA polymerase activity / DNA replication / viral translational frameshifting / DNA damage response / protein homodimerization activity / ATP hydrolysis activity / DNA binding / ATP binding / metal ion binding / identical protein binding / cytosol Similarity search - Function | ||||||
Biological species | ![]() ![]() ![]() ![]() | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.6 Å | ||||||
![]() | Oakley, A.J. / Xu, Z.-Q. / Dixon, N.E. | ||||||
Funding support | ![]()
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![]() | ![]() Title: Structural characterisation of the complete cycle of sliding clamp loading in Escherichia coli. Authors: Zhi-Qiang Xu / Slobodan Jergic / Allen T Y Lo / Alok C Pradhan / Simon H J Brown / James C Bouwer / Harshad Ghodke / Peter J Lewis / Gökhan Tolun / Aaron J Oakley / Nicholas E Dixon / ![]() Abstract: Ring-shaped DNA sliding clamps are essential for DNA replication and genome maintenance. Clamps need to be opened and chaperoned onto DNA by clamp loader complexes (CLCs). Detailed understanding of ...Ring-shaped DNA sliding clamps are essential for DNA replication and genome maintenance. Clamps need to be opened and chaperoned onto DNA by clamp loader complexes (CLCs). Detailed understanding of the mechanisms by which CLCs open and place clamps around DNA remains incomplete. Here, we present a series of six structures of the Escherichia coli CLC bound to an open or closed clamp prior to and after binding to a primer-template DNA, representing the most significant intermediates in the clamp loading process. We show that the ATP-bound CLC first binds to a clamp, then constricts to hold onto it. The CLC then expands to open the clamp with a gap large enough for double-stranded DNA to enter. Upon binding to DNA, the CLC constricts slightly, allowing clamp closing around DNA. These structures provide critical high-resolution snapshots of clamp loading by the E. coli CLC, revealing how the molecular machine works. | ||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 1.2 MB | Display | ![]() |
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PDB format | ![]() | 815.5 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 40083MC ![]() 8giyC ![]() 8gizC ![]() 8gj0C ![]() 8gj1C ![]() 8gj3C M: map data used to model this data C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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Components
-DNA polymerase III subunit ... , 4 types, 6 molecules ABCDEF
#1: Protein | Mass: 38745.574 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() | ||||
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#2: Protein | Mass: 71228.648 Da / Num. of mol.: 3 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() #3: Protein | | Mass: 36980.484 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() #4: Protein | | Mass: 15188.276 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Details: DNA polymerase III subunit psi / Source: (gene. exp.) ![]() ![]() ![]() ![]() |
-Protein , 1 types, 2 molecules HI
#5: Protein | Mass: 40630.508 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() |
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-DNA chain , 2 types, 2 molecules XY
#6: DNA chain | Mass: 7097.624 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) ![]() ![]() |
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#7: DNA chain | Mass: 10063.474 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) ![]() ![]() |
-Non-polymers , 4 types, 13 molecules 






#8: Chemical | #9: Chemical | #10: Chemical | #11: Chemical | ChemComp-ZN / |
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-Details
Has ligand of interest | N |
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Has protein modification | N |
-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
Component | Name: E. coli clamp loader with closed clamp on primed template DNA Type: COMPLEX Details: Clamp loader complex composed of DNA polymerase III delta tau(3) delta' chi and psi subunits. Clamp composed of DNA polymerase III beta(2) subunits. Entity ID: #1-#7 / Source: MULTIPLE SOURCES | |||||||||||||||||||||||||||||||||||||||||||||
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Molecular weight | Value: 0.419 MDa / Experimental value: NO | |||||||||||||||||||||||||||||||||||||||||||||
Source (natural) | Organism: ![]() ![]() | |||||||||||||||||||||||||||||||||||||||||||||
Source (recombinant) | Organism: ![]() ![]() | |||||||||||||||||||||||||||||||||||||||||||||
Buffer solution | pH: 7.6 Details: 30 mM Tris-HCl pH 7.6, 5 mM MgCl2, 2 mM ADP, 0.5 mM AlCl3, 5 mM NaF, 5 mM dithiothreitol, 0.25 mM EDTA, 2% glycerol. | |||||||||||||||||||||||||||||||||||||||||||||
Buffer component |
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Specimen | Conc.: 1.5 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES Details: 30 microL of 6.0 microM delta/tau3/delta' complex was mixed with chi/psi complex, beta, and p/t DNA (annealed DNA oligonucleotides) at a molar ratio of 1:1.3 and dialysed at 4 degrees C ...Details: 30 microL of 6.0 microM delta/tau3/delta' complex was mixed with chi/psi complex, beta, and p/t DNA (annealed DNA oligonucleotides) at a molar ratio of 1:1.3 and dialysed at 4 degrees C against 250 mL of 30 mM Tris-HCl pH 7.6, 5 mM MgCl2, 2 mM ADP, 0.5 mM AlCl3, 5 mM NaF, 5 mM dithiothreitol, 0.25 mM EDTA, 2% glycerol. | |||||||||||||||||||||||||||||||||||||||||||||
Specimen support | Details: Used a Zepto Low-pressure plasma systems (PLASMA CLEANER) (Diener Electronic) at 10% power for 120 seconds. Grid material: GOLD / Grid mesh size: 300 divisions/in. / Grid type: UltrAuFoil R1.2/1.3 | |||||||||||||||||||||||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 279 K Details: 3 uL of sample was applied onto a Ultrafoil Au R1.2/1.3 grid. Blot for 4.5 s with no extra force before plunging into liquid 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 / Nominal magnification: 165000 X / Nominal defocus max: 1300 nm / Nominal defocus min: 400 nm / Cs: 2.7 mm / C2 aperture diameter: 70 µm / Alignment procedure: COMA FREE |
Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
Image recording | Average exposure time: 6 sec. / Electron dose: 60 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Num. of grids imaged: 1 / Num. of real images: 1703 |
EM imaging optics | Energyfilter name: GIF Bioquantum / Details: unfiltered mode |
Image scans | Width: 4096 / Height: 4096 / Movie frames/image: 60 / Used frames/image: 1-60 |
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Processing
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EM software |
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CTF correction | Details: CTF refinement per-particle was performed in RELION before final 3D reconstruction. Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 600000 | ||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 2.6 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 452000 / Algorithm: BACK PROJECTION / Num. of class averages: 2 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||
Atomic model building | Protocol: FLEXIBLE FIT / Space: REAL | ||||||||||||||||||||||||||||||||||||||||
Atomic model building |
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Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||||||||||||||||||
Displacement parameters | Biso mean: 100.76 Å2 | ||||||||||||||||||||||||||||||||||||||||
Refine LS restraints |
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