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Open data
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Basic information
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Title | Structure of human Apoferritin obtained from ssDNA coated grid | |||||||||
![]() | Final Map | |||||||||
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Function / homology | ![]() iron ion sequestering activity / : / ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | ![]() ![]() | |||||||||
![]() | Hrebik D / Plevka P | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Polyelectrolyte coating of cryo-EM grids improves lateral distribution and prevents aggregation of macromolecules. Authors: Dominik Hrebík / Mária Gondová / Lucie Valentová / Tibor Füzik / Antonín Přidal / Jiří Nováček / Pavel Plevka / ![]() Abstract: Cryo-electron microscopy (cryo-EM) is one of the primary methods used to determine the structures of macromolecules and their complexes. With the increased availability of cryo-electron microscopes, ...Cryo-electron microscopy (cryo-EM) is one of the primary methods used to determine the structures of macromolecules and their complexes. With the increased availability of cryo-electron microscopes, the preparation of high-quality samples has become a bottleneck in the cryo-EM structure-determination pipeline. Macromolecules can be damaged during the purification or preparation of vitrified samples for cryo-EM, making them prone to binding to the grid support, to aggregation or to the adoption of preferential orientations at the air-water interface. Here, it is shown that coating cryo-EM grids with a negatively charged polyelectrolyte, such as single-stranded DNA, before applying the sample reduces the aggregation of macromolecules and improves their distribution. The single-stranded DNA-coated grids enabled the determination of high-resolution structures from samples that aggregated on conventional grids. The polyelectrolyte coating reduces the diffusion of macromolecules and thus may limit the negative effects of the contact of macromolecules with the grid support and blotting paper, as well as of the shear forces on macromolecules during grid blotting. Coating grids with polyelectrolytes can readily be employed in any laboratory dealing with cryo-EM sample preparation, since it is fast, simple, inexpensive and does not require specialized equipment. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 71.8 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 19.9 KB 19.9 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 18.1 KB | Display | ![]() |
Images | ![]() | 82.6 KB | ||
Others | ![]() ![]() | 77.9 MB 77.9 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 7zg7MC ![]() 7ze1C ![]() 7zfwC M: atomic model generated by this map C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
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Annotation | Final Map | ||||||||||||||||||||
Voxel size | X=Y=Z: 0.4525 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: Half map 1
File | emd_14705_half_map_1.map | ||||||||||||
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Annotation | Half map 1 | ||||||||||||
Projections & Slices |
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Density Histograms |
-Half map: Half map 2
File | emd_14705_half_map_2.map | ||||||||||||
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Annotation | Half map 2 | ||||||||||||
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Density Histograms |
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Sample components
-Entire : human heavy chain apoferritin
Entire | Name: human heavy chain apoferritin |
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Components |
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-Supramolecule #1: human heavy chain apoferritin
Supramolecule | Name: human heavy chain apoferritin / type: complex / Chimera: Yes / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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Source (natural) | Organism: ![]() ![]() |
Recombinant expression | Organism: ![]() ![]() ![]() |
Molecular weight | Theoretical: 20 KDa |
-Macromolecule #1: Ferritin heavy chain
Macromolecule | Name: Ferritin heavy chain / type: protein_or_peptide / ID: 1 / Number of copies: 24 / Enantiomer: LEVO / EC number: ![]() |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 20.116547 KDa |
Recombinant expression | Organism: ![]() ![]() ![]() |
Sequence | String: TSQVRQNYHQ DSEAAINRQI NLELYASYVY LSMSYYFDRD DVALKNFAKY FLHQSHEERE HAEKLMKLQN QRGGRIFLQD IKKPDCDDW ESGLNAMECA LHLEKNVNQS LLELHKLATD KNDPHLCDFI ETHYLNEQVK AIKELGDHVT NLRKMGAPES G LAEYLFDK HTLG |
-Macromolecule #2: ZINC ION
Macromolecule | Name: ZINC ION / type: ligand / ID: 2 / Number of copies: 270 / Formula: ZN |
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Molecular weight | Theoretical: 65.409 Da |
-Macromolecule #3: SODIUM ION
Macromolecule | Name: SODIUM ION / type: ligand / ID: 3 / Number of copies: 112 |
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Molecular weight | Theoretical: 22.99 Da |
-Macromolecule #4: water
Macromolecule | Name: water / type: ligand / ID: 4 / Number of copies: 2680 / Formula: HOH |
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Molecular weight | Theoretical: 18.015 Da |
Chemical component information | ![]() ChemComp-HOH: |
-Experimental details
-Structure determination
Method | ![]() |
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Aggregation state | particle |
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Sample preparation
Concentration | 4.0 mg/mL | ||||||||||||
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Buffer | pH: 7.5 Component:
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Grid | Model: Quantifoil R2/2 / Material: COPPER / Mesh: 300 / Support film - Material: CARBON / Support film - topology: HOLEY / Support film - Film thickness: 5.0 nm / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Atmosphere: NITROGEN | ||||||||||||
Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 277.15 K / Instrument: FEI VITROBOT MARK IV Details: 6 s blot time,30 s waiting time, ssDNA covered grid. |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | C2 aperture diameter: 50.0 µm / Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD![]() |
Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN |
Image recording | Film or detector model: FEI FALCON IV (4k x 4k) / Digitization - Dimensions - Width: 4096 pixel / Digitization - Dimensions - Height: 4096 pixel / Digitization - Sampling interval: 14.0 µm / Number grids imaged: 1 / Number real images: 3282 / Average exposure time: 4.08 sec. / Average electron dose: 40.0 e/Å2 |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |