+ Open data
Open data
- Basic information
Basic information
| Entry |  | ||||||||||||||||||
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| Title | Consensus volume for (Nap1)2-Kap114-H2A-H2B | ||||||||||||||||||
|  Map data | Consensus volume. | ||||||||||||||||||
|  Sample | 
 | ||||||||||||||||||
|  Keywords | Histone / Chaperone / Import / Nucleosome Assembly / TRANSPORT PROTEIN | ||||||||||||||||||
| Biological species |   Saccharomyces cerevisiae (brewer's yeast) | ||||||||||||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 3.2 Å | ||||||||||||||||||
|  Authors | Jiou J / Fung HYJ / Chook YM | ||||||||||||||||||
| Funding support |  United States, 5 items 
 | ||||||||||||||||||
|  Citation |  Journal: J Cell Biol / Year: 2025 Title: Nap1 and Kap114 co-chaperone H2A-H2B and facilitate targeted histone release in the nucleus. Authors: Ho Yee Joyce Fung / Jenny Jiou / Ashley B Niesman / Natalia E Bernardes / Yuh Min Chook /  Abstract: Core histones, synthesized and processed in the cytoplasm, must be chaperoned as they are transported into the nucleus for nucleosome assembly. The importin Kap114 transports H2A-H2B into the yeast ...Core histones, synthesized and processed in the cytoplasm, must be chaperoned as they are transported into the nucleus for nucleosome assembly. The importin Kap114 transports H2A-H2B into the yeast nucleus, where RanGTP facilitates histone release. Kap114 and H2A-H2B also bind the histone chaperone Nap1, but how Nap1 and Kap114 cooperate in transport and nucleosome assembly remains unclear. Here, biochemical and structural analyses show that Kap114, H2A-H2B, and a Nap1 dimer (Nap12) associate in the absence and presence of RanGTP to form equimolar complexes. A previous study had shown that RanGTP reduces Kap114's ability to chaperone H2A-H2B, but a new cryo-EM structure of the Nap12•H2A-H2B•Kap114•RanGTP complex explains how both Kap114 and Nap12 interact with H2A-H2B, restoring its chaperoning within the assembly while effectively depositing it into nucleosomes. Together, our results suggest that Kap114 and Nap12 provide a sheltered path that facilitates the transfer of H2A-H2B from Kap114 to Nap12, ultimately directing its specific deposition into nucleosomes. | ||||||||||||||||||
| History | 
 | 
- Structure visualization
Structure visualization
| Supplemental images | 
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- Downloads & links
Downloads & links
-EMDB archive
| Map data |  emd_44122.map.gz | 211 MB |  EMDB map data format | |
|---|---|---|---|---|
| Header (meta data) |  emd-44122-v30.xml  emd-44122.xml | 17.6 KB 17.6 KB | Display Display |  EMDB header | 
| FSC (resolution estimation) |  emd_44122_fsc.xml | 22 KB | Display |  FSC data file | 
| Images |  emd_44122.png | 59 KB | ||
| Filedesc metadata |  emd-44122.cif.gz | 4.8 KB | ||
| Others |  emd_44122_half_map_1.map.gz  emd_44122_half_map_2.map.gz | 392 MB 392 MB | ||
| Archive directory |  http://ftp.pdbj.org/pub/emdb/structures/EMD-44122  ftp://ftp.pdbj.org/pub/emdb/structures/EMD-44122 | HTTPS FTP | 
-Validation report
| Summary document |  emd_44122_validation.pdf.gz | 891.7 KB | Display |  EMDB validaton report | 
|---|---|---|---|---|
| Full document |  emd_44122_full_validation.pdf.gz | 891.2 KB | Display | |
| Data in XML |  emd_44122_validation.xml.gz | 24.1 KB | Display | |
| Data in CIF |  emd_44122_validation.cif.gz | 31.5 KB | Display | |
| Arichive directory |  https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-44122  ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-44122 | HTTPS FTP | 
-Related structure data
- Links
Links
| EMDB pages |  EMDB (EBI/PDBe) /  EMDataResource | 
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- Map
Map
| File |  Download / File: emd_44122.map.gz / Format: CCP4 / Size: 421.9 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Annotation | Consensus volume. | ||||||||||||||||||||||||||||||||||||
| Projections & slices | Image control
 
 Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
| Voxel size | X=Y=Z: 0.83 Å | ||||||||||||||||||||||||||||||||||||
| Density | 
 | ||||||||||||||||||||||||||||||||||||
| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML: 
 | 
-Supplemental data
-Half map: Half map A.
| File | emd_44122_half_map_1.map | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Annotation | Half map A. | ||||||||||||
| Projections & Slices | 
 | ||||||||||||
| Density Histograms | 
-Half map: Half map B.
| File | emd_44122_half_map_2.map | ||||||||||||
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| Annotation | Half map B. | ||||||||||||
| Projections & Slices | 
 | ||||||||||||
| Density Histograms | 
- Sample components
Sample components
-Entire : Crosslinked mixture of Kap114 with Nap1 and H2A-H2B
| Entire | Name: Crosslinked mixture of Kap114 with Nap1 and H2A-H2B | 
|---|---|
| Components | 
 | 
-Supramolecule #1: Crosslinked mixture of Kap114 with Nap1 and H2A-H2B
| Supramolecule | Name: Crosslinked mixture of Kap114 with Nap1 and H2A-H2B / type: complex / ID: 1  / Parent: 0  / Macromolecule list: #1-#4 Details: Nap1 and H2A-H2B were pre-complexed with excess histones, and Kap114 was added before mild crosslinking and SEC separation. | 
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| Source (natural) | Organism:   Saccharomyces cerevisiae (brewer's yeast) | 
| Molecular weight | Theoretical: 72 KDa | 
-Experimental details
-Structure determination
| Method | cryo EM | 
|---|---|
|  Processing | single particle reconstruction | 
| Aggregation state | particle | 
- Sample preparation
Sample preparation
| Concentration | 1.2 mg/mL | |||||||||||||||
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| Buffer | pH: 7.4 Component: 
 | |||||||||||||||
| Grid | Model: Quantifoil / Material: COPPER / Support film - Material: CARBON / Support film - topology: HOLEY | |||||||||||||||
| Vitrification | Cryogen name: ETHANE / Chamber humidity: 95 % / Chamber temperature: 280 K / Instrument: FEI VITROBOT MARK IV | |||||||||||||||
| Details | Crosslinked sample. | 
- Electron microscopy
Electron microscopy
| Microscope | FEI TITAN KRIOS | 
|---|---|
| Specialist optics | Energy filter - Slit width: 20 eV | 
| Image recording | Film or detector model: GATAN K3 (6k x 4k) / Number grids imaged: 1 / Number real images: 1080 / Average exposure time: 5.4 sec. / Average electron dose: 59.0 e/Å2 | 
| Electron beam | Acceleration voltage: 300 kV / Electron source:  FIELD EMISSION GUN | 
| Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.4 µm / Nominal defocus min: 0.9 µm / Nominal magnification: 105000 | 
| Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER | 
| Experimental equipment |  Model: Titan Krios / Image courtesy: FEI Company | 
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