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Yorodumi- PDB-9r9h: Cryo-EM structure of an extracellular contractile injection syste... -
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Open data
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Basic information
| Entry | Database: PDB / ID: 9r9h | |||||||||||||||||||||
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| Title | Cryo-EM structure of an extracellular contractile injection system in Salmonella enterica subspecies salamae, the sheath and inner tube module in extended state. | |||||||||||||||||||||
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Keywords | CONTRACTILE PROTEIN / Contractile injection system / Salmonella enterica subspecies salamae | |||||||||||||||||||||
| Biological species | Salmonella enterica subsp. salamae (bacteria) | |||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / helical reconstruction / cryo EM / Resolution: 2.28 Å | |||||||||||||||||||||
Authors | Ejaz, R.N. / Tillmann, H.P. / Sofos, N.H. / Siborova, M. / Taylor, N.M.I. | |||||||||||||||||||||
| Funding support | Denmark, 1items
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Citation | Journal: Nat Commun / Year: 2026Title: Structure of a contractile injection system in Salmonella enterica subsp. salamae. Authors: Rooshanie N Ejaz / Kristin Funke / Claudia S Kielkopf / Freddie J O Martin / Marta Šiborová / Ivo A Hendriks / Nicholas H Sofos / Tillmann Pape / Eva M Steiner-Rebrova / Michael L Nielsen ...Authors: Rooshanie N Ejaz / Kristin Funke / Claudia S Kielkopf / Freddie J O Martin / Marta Šiborová / Ivo A Hendriks / Nicholas H Sofos / Tillmann Pape / Eva M Steiner-Rebrova / Michael L Nielsen / Marc Erhardt / Nicholas M I Taylor / ![]() Abstract: Extracellular contractile injection systems (eCISs) are phage-derived nanomachines used by bacteria to deliver effectors into target cells. Well-studied examples include the Photorhabdus asymbiotica ...Extracellular contractile injection systems (eCISs) are phage-derived nanomachines used by bacteria to deliver effectors into target cells. Well-studied examples include the Photorhabdus asymbiotica virulence cassettes and the antifeeding prophage from Serratia entomophila, which have been engineered for heterologous cargo delivery. Recent genomic analyses identified eCIS gene clusters in the opportunistic human pathogen Salmonella enterica subspecies salamae, but their structure, function, and biotechnological potential remain unexplored. Here, we report a high-resolution cryo-electron microscopy structure of the S. enterica eCIS. Our atomic models reveal a distinctive sheath architecture, an expansive cage-like shell around a central spike, and an associated integral membrane protein. We identify a putative effector encoded within the operon exhibiting mild periplasmic toxicity and provide evidence that the S. enterica eCIS deviates from canonical eCISs by interacting with the inner membrane. Guided by these structural features, we uncover, to the best of our knowledge, a previously unannotated cluster of contractile injection systems (CISs). Together, our findings expand the known diversity of CISs' structures and functions, and lay the groundwork for engineering customisable protein delivery platforms. | |||||||||||||||||||||
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Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 9r9h.cif.gz | 5.1 MB | Display | PDBx/mmCIF format |
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| PDB format | pdb9r9h.ent.gz | Display | PDB format | |
| PDBx/mmJSON format | 9r9h.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/r9/9r9h ftp://data.pdbj.org/pub/pdb/validation_reports/r9/9r9h | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 53857MC ![]() 9r9aC ![]() 9r9iC ![]() 9r9nC ![]() 9rceC M: map data used to model this data C: citing same article ( |
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Links
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Assembly
| Deposited unit | ![]()
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Components
| #1: Protein | Mass: 57351.930 Da / Num. of mol.: 18 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Salmonella enterica subsp. salamae (bacteria)Gene: G0C45_16390 / Production host: ![]() #2: Protein | Mass: 17091.271 Da / Num. of mol.: 18 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Salmonella enterica subsp. salamae (bacteria)Gene: G0C45_16385 / Production host: ![]() Has protein modification | N | |
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-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
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| EM experiment | Aggregation state: HELICAL ARRAY / 3D reconstruction method: helical reconstruction |
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Sample preparation
| Component | Name: Helical complex of the sheath and inner tube module of a contractile injection system Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
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| Molecular weight | Experimental value: NO |
| Source (natural) | Organism: Salmonella enterica subsp. salamae (bacteria) |
| Source (recombinant) | Organism: ![]() |
| Buffer solution | pH: 7.4 |
| Specimen | Conc.: 20 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Specimen support | Details: 5mA / Grid mesh size: 200 divisions/in. / Grid type: Quantifoil R2/2 |
| Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Chamber temperature: 277.15 K |
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Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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| Microscopy | Model: TFS KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: SPOT SCAN |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2500 nm / Nominal defocus min: 500 nm / Cs: 2.7 mm |
| Image recording | Electron dose: 41 e/Å2 / Film or detector model: FEI FALCON IV (4k x 4k) |
| EM imaging optics | Energyfilter name: TFS Selectris X / Energyfilter slit width: 10 eV |
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Processing
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||
| Helical symmerty | Angular rotation/subunit: 21.6 ° / Axial rise/subunit: 39.2 Å / Axial symmetry: C6 | ||||||||||||||||||||||||||||
| Particle selection | Num. of particles selected: 142404 | ||||||||||||||||||||||||||||
| 3D reconstruction | Resolution: 2.28 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 136877 / Num. of class averages: 1 / Symmetry type: HELICAL | ||||||||||||||||||||||||||||
| Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||||||
| Displacement parameters | Biso mean: 84.88 Å2 | ||||||||||||||||||||||||||||
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About Yorodumi



Salmonella enterica subsp. salamae (bacteria)
Denmark, 1items
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FIELD EMISSION GUN