[English] 日本語
Yorodumi- EMDB-57737: TnsC-focused cryo-EM volume of the PseCascade-TniQ-TnsC complex b... -
+
Open data
-
Basic information
| Entry | ![]() | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Title | TnsC-focused cryo-EM volume of the PseCascade-TniQ-TnsC complex bound to TnsB-hook motifs | |||||||||
Map data | ||||||||||
Sample |
| |||||||||
Keywords | Transposase / DNA-binding / RNA-binding / CRISPR-Cas / CRISPR-associated transposon / DNA BINDING PROTEIN | |||||||||
| Biological species | Pseudoalteromonas sp. S983 (bacteria) | |||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 3.0 Å | |||||||||
Authors | Finocchio G / Oberli S / Schmitz M / Jinek M | |||||||||
| Funding support | European Union, Switzerland, 2 items
| |||||||||
Citation | Journal: bioRxiv / Year: 2026Title: Structural basis of RNA-guided DNA integration by type I CRISPR-associated transposases. Authors: Giada Finocchio / Seraina Oberli / George Lampe / Michael Schmitz / Samuel H Sternberg / Martin Jinek / ![]() Abstract: CRISPR-associated transposases (CASTs) achieve site-specific DNA integration by coupling the RNA-guided targeting action of a nuclease-deficient CRISPR-Cas system with the assembly of a Tn7-like ...CRISPR-associated transposases (CASTs) achieve site-specific DNA integration by coupling the RNA-guided targeting action of a nuclease-deficient CRISPR-Cas system with the assembly of a Tn7-like transpososome complex. Understanding the detailed mechanisms of this elaborate process is paramount to engineering CAST systems into programmable genetic tools. The type I-F CAST (CAST) displays the highest activity in mammalian cells to date and has been the subject of extensive directed evolution, but efforts to rationally engineer further improvements have been hampered by critical gaps in our understanding of transpososome assembly and activation. Here we use cryo-EM structural analysis, validated by DNA transposition assays, to visualize the CAST system in a series of functional states that define the stepwise mechanism of RNA-guided DNA integration. The structure of a target DNA-bound Cascade-TniQ-TnsC complex reveals that conformational changes induced by R-loop formation are coupled to target DNA stabilization and TnsC heptamerization, which in turn recruits the TnsAB transposase via conserved interactions with its C-terminal tail. Finally, the structure of the 1.2 MDa CAST transpososome holocomplex reveals specific TnsC-TnsB and TnsB-target DNA interactions that drive allosteric remodelling of the TnsB catalytic site to activate donor DNA integration. Together, these findings establish a unified structural and mechanistic blueprint for RNA-guided DNA integration and lay the foundation for engineering next-generation DNA insertion systems for genome editing applications. | |||||||||
| History |
|
-
Structure visualization
| Supplemental images |
|---|
-
Downloads & links
-EMDB archive
| Map data | emd_57737.map.gz | 410.6 MB | EMDB map data format | |
|---|---|---|---|---|
| Header (meta data) | emd-57737-v30.xml emd-57737.xml | 22.1 KB 22.1 KB | Display Display | EMDB header |
| FSC (resolution estimation) | emd_57737_fsc.xml | 27.6 KB | Display | FSC data file |
| Images | emd_57737.png | 71.4 KB | ||
| Masks | emd_57737_msk_1.map | 824 MB | Mask map | |
| Filedesc metadata | emd-57737.cif.gz | 5.5 KB | ||
| Others | emd_57737_half_map_1.map.gz emd_57737_half_map_2.map.gz | 765.6 MB 765.5 MB | ||
| Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-57737 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-57737 | HTTPS FTP |
-Related structure data
-
Links
| EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
|---|
-
Map
| File | Download / File: emd_57737.map.gz / Format: CCP4 / Size: 824 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
| Voxel size | X=Y=Z: 0.65 Å | ||||||||||||||||||||||||||||||||||||
| Density |
| ||||||||||||||||||||||||||||||||||||
| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML:
|
-Supplemental data
-Mask #1
| File | emd_57737_msk_1.map | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Projections & Slices |
| ||||||||||||
| Density Histograms |
-Half map: #2
| File | emd_57737_half_map_1.map | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Projections & Slices |
| ||||||||||||
| Density Histograms |
-Half map: #1
| File | emd_57737_half_map_2.map | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Projections & Slices |
| ||||||||||||
| Density Histograms |
-
Sample components
-Entire : PseCascade-TniQ-TnsC complex bound to TnsB-hook motifs
| Entire | Name: PseCascade-TniQ-TnsC complex bound to TnsB-hook motifs |
|---|---|
| Components |
|
-Supramolecule #1: PseCascade-TniQ-TnsC complex bound to TnsB-hook motifs
| Supramolecule | Name: PseCascade-TniQ-TnsC complex bound to TnsB-hook motifs type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#9 Details: PseCascade-TniQ-TnsC complex bound to seven C-terminal PseTnsB-hooks. The CRISPR RNA (crRNA) is base-paired with a double-stranded DNA target. The hook comprises residues 605-613 of TnsB ...Details: PseCascade-TniQ-TnsC complex bound to seven C-terminal PseTnsB-hooks. The CRISPR RNA (crRNA) is base-paired with a double-stranded DNA target. The hook comprises residues 605-613 of TnsB (843-851 of the TnsA-TnsB fusion). |
|---|---|
| Source (natural) | Organism: Pseudoalteromonas sp. S983 (bacteria) |
| Molecular weight | Theoretical: 740 KDa |
-Experimental details
-Structure determination
| Method | cryo EM |
|---|---|
Processing | single particle reconstruction |
| Aggregation state | particle |
-
Sample preparation
| Concentration | 2.6 mg/mL | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Buffer | pH: 7.5 Component:
| ||||||||||||||||||||||||
| Grid | Model: Quantifoil R1.2/1.3 / Material: GOLD / Mesh: 300 / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 60 sec. / Pretreatment - Atmosphere: AIR / Pretreatment - Pressure: 0.039 kPa | ||||||||||||||||||||||||
| Vitrification | Cryogen name: ETHANE-PROPANE / Chamber humidity: 100 % / Chamber temperature: 277.15 K / Instrument: FEI VITROBOT MARK IV | ||||||||||||||||||||||||
| Details | The sample was prepared by co-precipitation, using His-MBP-tagged TnsAB bound to a double-stranded right-end substrate as bait to capture Cascade-TniQ and TnsC. |
-
Electron microscopy
| Microscope | TFS KRIOS |
|---|---|
| Image recording | Film or detector model: GATAN K3 (6k x 4k) / Detector mode: SUPER-RESOLUTION / Digitization - Dimensions - Width: 5760 pixel / Digitization - Dimensions - Height: 4092 pixel / Number grids imaged: 1 / Number real images: 11374 / Average exposure time: 1.25 sec. / Average electron dose: 60.95 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: 1.0 µm / Nominal magnification: 130000 |
| Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN |
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
+
Image processing
-Atomic model buiding 1
| Initial model | Chain - Source name: AlphaFold / Chain - Initial model type: in silico model |
|---|---|
| Refinement | Space: REAL / Protocol: FLEXIBLE FIT / Overall B value: 83.7 Target criteria: Real-space map-model correlation and geometry restraints |
Movie
Controller
About Yorodumi



Keywords
Pseudoalteromonas sp. S983 (bacteria)
Authors
Switzerland, 2 items
Citation















Z (Sec.)
Y (Row.)
X (Col.)












































FIELD EMISSION GUN

