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Open data
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Basic information
| Entry | ![]()  | |||||||||
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| Title | Dimer-2 SPARTA complex | |||||||||
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 Sample | 
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 Keywords | SPARTA / TIR / prokaryotic argonaute / IMMUNE SYSTEM | |||||||||
| Biological species |  Maribacter polysiphoniae (bacteria) | |||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 3.8 Å | |||||||||
 Authors | Ekundayo B / Ni DC / Lu XH / Stahlberg H | |||||||||
| Funding support |   Switzerland, 2 items 
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 Citation |  Journal: Sci Adv / Year: 2023Title: Activation mechanism of a short argonaute-TIR prokaryotic immune system. Authors: Dongchun Ni / Xuhang Lu / Henning Stahlberg / Babatunde Ekundayo /   ![]() Abstract: Short prokaryotic argonaute (pAgo) and toll/interleukin-1 receptor/resistance protein (TIR)-analog of PAZ (APAZ) form a heterodimeric SPARTA complex that provides immunity to its prokaryotic host ...Short prokaryotic argonaute (pAgo) and toll/interleukin-1 receptor/resistance protein (TIR)-analog of PAZ (APAZ) form a heterodimeric SPARTA complex that provides immunity to its prokaryotic host through an abortive infection mechanism. Monomeric SPARTA senses foreign RNA/DNA duplexes to assemble an active tetramer resulting in cell death by nicotinamide adenine dinucleotide (oxidized form) (NAD) depletion via an unknown mechanism. We report nine structures of SPARTA in different functional states at a resolution range of 4.2 to 2.9 angstroms, revealing its activation mechanism. Inactive SPARTA monomers bind to RNA/DNA duplexes to form symmetric dimers mediated by the association of Ago subunits. The initiation of tetramer assembly induces flexibility of the TIR domains enabling a symmetry-breaking rotational movement of a TIR domain in the dimer units which facilitates the TIR oligomerization, resulting in the formation of the substrate binding pocket and the activation of the SPARTA complex's NADase activity. Our findings provide detailed structural and mechanistic insights into activating a short argonaute defense system.  | |||||||||
| History | 
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Structure visualization
| Supplemental images | 
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Downloads & links
-EMDB archive
| Map data |  emd_17302.map.gz | 51.7 MB |  EMDB map data format | |
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| Header (meta data) |  emd-17302-v30.xml emd-17302.xml | 13.5 KB 13.5 KB  | Display Display  |  EMDB header | 
| FSC (resolution estimation) |  emd_17302_fsc.xml | 9.9 KB | Display |  FSC data file | 
| Images |  emd_17302.png | 56.1 KB | ||
| Masks |  emd_17302_msk_1.map | 103 MB |  Mask map | |
| Others |  emd_17302_half_map_1.map.gz emd_17302_half_map_2.map.gz | 95.4 MB 95.4 MB  | ||
| Archive directory |  http://ftp.pdbj.org/pub/emdb/structures/EMD-17302 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-17302 | HTTPS FTP  | 
-Validation report
| Summary document |  emd_17302_validation.pdf.gz | 1.3 MB | Display |  EMDB validaton report | 
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| Full document |  emd_17302_full_validation.pdf.gz | 1.3 MB | Display | |
| Data in XML |  emd_17302_validation.xml.gz | 18.3 KB | Display | |
| Data in CIF |  emd_17302_validation.cif.gz | 23.5 KB | Display | |
| Arichive directory |  https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-17302 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-17302 | HTTPS FTP  | 
-Related structure data
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Links
| EMDB pages |  EMDB (EBI/PDBe) /  EMDataResource | 
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Map
| File |  Download / File: emd_17302.map.gz / Format: CCP4 / Size: 103 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: 1.21 Å | ||||||||||||||||||||||||||||||||||||
| Density | 
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| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML: 
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-Supplemental data
-Mask #1
| File |  emd_17302_msk_1.map | ||||||||||||
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| Density Histograms | 
-Half map: #1
| File | emd_17302_half_map_1.map | ||||||||||||
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| Projections & Slices | 
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| Density Histograms | 
-Half map: #2
| File | emd_17302_half_map_2.map | ||||||||||||
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| Projections & Slices | 
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| Density Histograms | 
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Sample components
-Entire : heter complex of short argonaute-TIR antiviral defence system
| Entire | Name: heter complex of short argonaute-TIR antiviral defence system | 
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| Components | 
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-Supramolecule #1: heter complex of short argonaute-TIR antiviral defence system
| Supramolecule | Name: heter complex of short argonaute-TIR antiviral defence system type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#4  | 
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| Source (natural) | Organism:  Maribacter polysiphoniae (bacteria) | 
| Molecular weight | Theoretical: 500 KDa | 
-Experimental details
-Structure determination
| Method | cryo EM | 
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 Processing | single particle reconstruction | 
| Aggregation state | particle | 
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Sample preparation
| Concentration | 1 mg/mL | 
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| Buffer | pH: 7.5 | 
| Vitrification | Cryogen name: ETHANE | 
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Electron microscopy
| Microscope | FEI TITAN KRIOS | 
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| Image recording | Film or detector model: FEI FALCON IV (4k x 4k) / Average electron dose: 50.0 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: 2.5 µm / Nominal defocus min: 0.8 µm | 
| Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN | 
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company  | 
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Image processing
-Atomic model buiding 1
| Refinement | Protocol: AB INITIO MODEL | 
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Movie
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About Yorodumi




Keywords
Maribacter polysiphoniae (bacteria)
Authors
Switzerland, 2 items 
Citation

















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Y (Row.)
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FIELD EMISSION GUN

