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Open data
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Basic information
| Entry | Database: PDB / ID: 9kn3 | ||||||
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| Title | Cryo-EM structure of LptDEM complex from Escherichia coli | ||||||
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Keywords | MEMBRANE PROTEIN / LPS / Transporter / Complex | ||||||
| Function / homology | Function and homology informationtransporter complex / lipopolysaccharide transport / Gram-negative-bacterium-type cell outer membrane assembly / cell outer membrane / lipopolysaccharide binding Similarity search - Function | ||||||
| Biological species | ![]() | ||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.27 Å | ||||||
Authors | Tsukazaki, T. / Kohga, H. / Miyazaki, R. | ||||||
| Funding support | Japan, 1items
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Citation | Journal: Cell Rep / Year: 2025Title: Structural basis of lipopolysaccharide translocon assembly mediated by the small lipoprotein LptM. Authors: Ryoji Miyazaki / Mai Kimoto / Hidetaka Kohga / Tomoya Tsukazaki / ![]() Abstract: Gram-negative bacteria possess an outer membrane (OM) that acts as a barrier against toxic compounds. Lipopolysaccharide (LPS) in the outer leaflet of the OM is crucial for barrier function and is ...Gram-negative bacteria possess an outer membrane (OM) that acts as a barrier against toxic compounds. Lipopolysaccharide (LPS) in the outer leaflet of the OM is crucial for barrier function and is transported to the OM by the LPS transport system. The LPS translocon (the LptDE complex), mediates LPS assembly into the OM. Recently, the small lipoprotein LptM was identified as an LptDE interactor that facilitates LptD maturation. However, its mechanism remains unclear. Here, we investigate the detailed interaction between LptM and LptD. We find that LptM interacts with the folded LptD intermediate at the late stage of its maturation. Mutational analyses demonstrate that the N-terminal conserved region of LptM is essential for its function. Cryoelectron microscopy structural analysis of the Escherichia coli LptDEM complex, combined with biochemical analyses, reveals the molecular basis of the LptM-LptD interaction and its functional importance. Thus, we propose that LptM stabilizes LptD for proper assembly. | ||||||
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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 | 9kn3.cif.gz | 240.8 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9kn3.ent.gz | 151.2 KB | Display | PDB format |
| PDBx/mmJSON format | 9kn3.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Summary document | 9kn3_validation.pdf.gz | 1.4 MB | Display | wwPDB validaton report |
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| Full document | 9kn3_full_validation.pdf.gz | 1.4 MB | Display | |
| Data in XML | 9kn3_validation.xml.gz | 39.7 KB | Display | |
| Data in CIF | 9kn3_validation.cif.gz | 59.6 KB | Display | |
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/kn/9kn3 ftp://data.pdbj.org/pub/pdb/validation_reports/kn/9kn3 | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 62452MC M: map data used to model this data C: citing same article ( |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
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Assembly
| Deposited unit | ![]()
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Components
| #1: Protein | Mass: 87149.516 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() |
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| #2: Protein | Mass: 19479.148 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() |
| #3: Protein | Mass: 6727.348 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() |
| Has protein modification | Y |
-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
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| EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
| Component | Name: LptDEM complex in Nanodisc / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
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| Molecular weight | Experimental value: NO |
| Source (natural) | Organism: ![]() |
| Source (recombinant) | Organism: ![]() |
| Buffer solution | pH: 8 |
| Specimen | Conc.: 4.648 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
| Microscopy | Model: TFS GLACIOS |
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| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 200 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: -1600 nm / Nominal defocus min: -600 nm / Cs: 2.7 mm / C2 aperture diameter: 50 µm |
| Image recording | Electron dose: 50 e/Å2 / Film or detector model: FEI FALCON IV (4k x 4k) |
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Processing
| EM software | Name: PHENIX / Version: 1.20.1_4487: / Category: model refinement | ||||||||||||||||||||||||
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| CTF correction | Type: NONE | ||||||||||||||||||||||||
| Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 3.27 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 428907 / Symmetry type: POINT | ||||||||||||||||||||||||
| Atomic model building | B value: 108.5 / Protocol: AB INITIO MODEL | ||||||||||||||||||||||||
| Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||
| Displacement parameters | Biso mean: 72.57 Å2 | ||||||||||||||||||||||||
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About Yorodumi






Japan, 1items
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FIELD EMISSION GUN