+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-3516 | |||||||||
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Title | IBDV E6 population | |||||||||
Map data | ||||||||||
Sample |
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Biological species | Infectious bursal disease virus (Gumboro virus) | |||||||||
Method | subtomogram averaging / cryo EM / Resolution: 47.8 Å | |||||||||
Authors | Mata CP / Mertens J / Fontana J / Luque D / Allende-Ballestero C / Reguera D / Trus BL / Steven AC / Carrascosa JL / Caston JR | |||||||||
Citation | Journal: J Virol / Year: 2018 Title: The RNA-Binding Protein of a Double-Stranded RNA Virus Acts like a Scaffold Protein. Authors: Carlos P Mata / Johann Mertens / Juan Fontana / Daniel Luque / Carolina Allende-Ballestero / David Reguera / Benes L Trus / Alasdair C Steven / José L Carrascosa / José R Castón / Abstract: Infectious bursal disease virus (IBDV), a nonenveloped, double-stranded RNA (dsRNA) virus with a T=13 icosahedral capsid, has a virion assembly strategy that initiates with a precursor particle based ...Infectious bursal disease virus (IBDV), a nonenveloped, double-stranded RNA (dsRNA) virus with a T=13 icosahedral capsid, has a virion assembly strategy that initiates with a precursor particle based on an internal scaffold shell similar to that of tailed double-stranded DNA (dsDNA) viruses. In IBDV-infected cells, the assembly pathway results mainly in mature virions that package four dsRNA segments, although minor viral populations ranging from zero to three dsRNA segments also form. We used cryo-electron microscopy (cryo-EM), cryo-electron tomography, and atomic force microscopy to characterize these IBDV populations. The VP3 protein was found to act as a scaffold protein by building an irregular, ∼40-Å-thick internal shell without icosahedral symmetry, which facilitates formation of a precursor particle, the procapsid. Analysis of IBDV procapsid mechanical properties indicated a VP3 layer beneath the icosahedral shell, which increased the effective capsid thickness. Whereas scaffolding proteins are discharged in tailed dsDNA viruses, VP3 is a multifunctional protein. In mature virions, VP3 is bound to the dsRNA genome, which is organized as ribonucleoprotein complexes. IBDV is an amalgam of dsRNA viral ancestors and traits from dsDNA and single-stranded RNA (ssRNA) viruses. Structural analyses highlight the constraint of virus evolution to a limited number of capsid protein folds and assembly strategies that result in a functional virion. We report the cryo-EM and cryo-electron tomography structures and the results of atomic force microscopy studies of the infectious bursal disease virus (IBDV), a double-stranded RNA virus with an icosahedral capsid. We found evidence of a new inner shell that might act as an internal scaffold during IBDV assembly. The use of an internal scaffold is reminiscent of tailed dsDNA viruses, which constitute the most successful self-replicating system on Earth. The IBDV scaffold protein is multifunctional and, after capsid maturation, is genome bound to form ribonucleoprotein complexes. IBDV encompasses numerous functional and structural characteristics of RNA and DNA viruses; we suggest that IBDV is a modern descendant of ancestral viruses and comprises different features of current viral lineages. | |||||||||
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_3516.map.gz | 5.9 MB | EMDB map data format | |
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Header (meta data) | emd-3516-v30.xml emd-3516.xml | 10.1 KB 10.1 KB | Display Display | EMDB header |
Images | emd_3516.png | 207.5 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-3516 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-3516 | HTTPS FTP |
-Validation report
Summary document | emd_3516_validation.pdf.gz | 232.8 KB | Display | EMDB validaton report |
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Full document | emd_3516_full_validation.pdf.gz | 231.9 KB | Display | |
Data in XML | emd_3516_validation.xml.gz | 5.8 KB | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-3516 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-3516 | HTTPS FTP |
-Related structure data
Related structure data | 3507C 3509C 3510C 3511C 3512C 3513C 3514C 3515C C: citing same article (ref.) |
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Similar structure data |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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-Map
File | Download / File: emd_3516.map.gz / Format: CCP4 / Size: 12.4 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 5.6 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 : Infectious bursal disease virus
Entire | Name: Infectious bursal disease virus (Gumboro virus) |
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Components |
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-Supramolecule #1: Infectious bursal disease virus
Supramolecule | Name: Infectious bursal disease virus / type: virus / ID: 1 / Parent: 0 / NCBI-ID: 10995 / Sci species name: Infectious bursal disease virus / Virus type: VIRION / Virus isolate: STRAIN / Virus enveloped: No / Virus empty: Yes |
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Host (natural) | Organism: Gallus gallus (chicken) |
Molecular weight | Experimental: 50 MDa |
Virus shell | Shell ID: 1 / Name: VP2 / Diameter: 700.0 Å / T number (triangulation number): 13 |
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | subtomogram averaging |
Aggregation state | particle |
-Sample preparation
Buffer | pH: 6.2 / Details: 25 mM PIPES pH 6.2, 150 mM NaCl, 20 mM CaCl2 |
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Grid | Model: Quantifoil R2/2 / Material: COPPER/RHODIUM / Mesh: 300 |
Vitrification | Cryogen name: ETHANE / Instrument: LEICA EM CPC |
-Electron microscopy
Microscope | FEI TECNAI 12 |
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Specialist optics | Energy filter - Name: GIF 2002 Gatan |
Image recording | Film or detector model: OTHER / Average electron dose: 1.0 e/Å2 |
Electron beam | Acceleration voltage: 120 kV / Electron source: LAB6 |
Electron optics | Calibrated defocus max: 4.0 µm / Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal magnification: 53600 |
Sample stage | Specimen holder model: GATAN 626 SINGLE TILT LIQUID NITROGEN CRYO TRANSFER HOLDER Cooling holder cryogen: NITROGEN |
-Image processing
Final reconstruction | Applied symmetry - Point group: I (icosahedral) / Algorithm: FOURIER SPACE / Resolution.type: BY AUTHOR / Resolution: 47.8 Å / Resolution method: FSC 0.5 CUT-OFF / Software - Name: Xmipp (ver. 2) / Number subtomograms used: 457 |
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Extraction | Number tomograms: 8 / Number images used: 457 / Software - Name: Bsoft (ver. 1.9) |
Final angle assignment | Type: PROJECTION MATCHING / Software - Name: Xmipp (ver. 2) |