+Open data
-Basic information
Entry | Database: PDB / ID: 7mu1 | |||||||||
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Title | Thermotoga maritima encapsulin shell | |||||||||
Components | Maritimacin | |||||||||
Keywords | VIRUS LIKE PARTICLE / Encapsulin / Ferritin-like protein / EncFLP / Thermotoga / FMN / Bacterial Nanocompartment | |||||||||
Function / homology | Function and homology information encapsulin nanocompartment / Hydrolases; Acting on peptide bonds (peptidases) / peptidase activity / iron ion transport / intracellular iron ion homeostasis / proteolysis Similarity search - Function | |||||||||
Biological species | Thermotoga maritima (bacteria) | |||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.3 Å | |||||||||
Authors | LaFrance, B.J. / Nogales, E. / Savage, D.F. | |||||||||
Funding support | United States, 2items
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Citation | Journal: Sci Rep / Year: 2021 Title: The encapsulin from Thermotoga maritima is a flavoprotein with a symmetry matched ferritin-like cargo protein. Authors: Benjamin J LaFrance / Caleb Cassidy-Amstutz / Robert J Nichols / Luke M Oltrogge / Eva Nogales / David F Savage / Abstract: Bacterial nanocompartments, also known as encapsulins, are an emerging class of protein-based 'organelles' found in bacteria and archaea. Encapsulins are virus-like icosahedral particles comprising a ...Bacterial nanocompartments, also known as encapsulins, are an emerging class of protein-based 'organelles' found in bacteria and archaea. Encapsulins are virus-like icosahedral particles comprising a ~ 25-50 nm shell surrounding a specific cargo enzyme. Compartmentalization is thought to create a unique chemical environment to facilitate catalysis and isolate toxic intermediates. Many questions regarding nanocompartment structure-function remain unanswered, including how shell symmetry dictates cargo loading and to what extent the shell facilitates enzymatic activity. Here, we explore these questions using the model Thermotoga maritima nanocompartment known to encapsulate a redox-active ferritin-like protein. Biochemical analysis revealed the encapsulin shell to possess a flavin binding site located at the interface between capsomere subunits, suggesting the shell may play a direct and active role in the function of the encapsulated cargo. Furthermore, we used cryo-EM to show that cargo proteins use a form of symmetry-matching to facilitate encapsulation and define stoichiometry. In the case of the Thermotoga maritima encapsulin, the decameric cargo protein with fivefold symmetry preferentially binds to the pentameric-axis of the icosahedral shell. Taken together, these observations suggest the shell is not simply a passive barrier-it also plays a significant role in the structure and function of the cargo enzyme. | |||||||||
History |
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-Structure visualization
Movie |
Movie viewer |
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Structure viewer | Molecule: MolmilJmol/JSmol |
-Downloads & links
-Download
PDBx/mmCIF format | 7mu1.cif.gz | 62.9 KB | Display | PDBx/mmCIF format |
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PDB format | pdb7mu1.ent.gz | 43.6 KB | Display | PDB format |
PDBx/mmJSON format | 7mu1.json.gz | Tree view | PDBx/mmJSON format | |
Others | Other downloads |
-Validation report
Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/mu/7mu1 ftp://data.pdbj.org/pub/pdb/validation_reports/mu/7mu1 | HTTPS FTP |
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-Related structure data
Related structure data | 24001MC M: map data used to model this data C: citing same article (ref.) |
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Similar structure data |
-Links
-Assembly
Deposited unit |
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Symmetry | Point symmetry: (Schoenflies symbol: I (icosahedral)) |
-Components
#1: Protein | Mass: 30369.615 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Thermotoga maritima (bacteria) / Gene: TM_0785 / Production host: Escherichia coli BL21(DE3) (bacteria) References: UniProt: Q9WZP2, Hydrolases; Acting on peptide bonds (peptidases) |
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#2: Chemical | ChemComp-FMN / |
Has ligand of interest | Y |
-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
-Sample preparation
Component | Name: 3.3A cryo-EM map of the T. maritima encapsulin shell / Type: ORGANELLE OR CELLULAR COMPONENT / Entity ID: #1 / Source: RECOMBINANT |
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Molecular weight | Value: 1.83 MDa / Experimental value: NO |
Source (natural) | Organism: Thermotoga maritima (bacteria) |
Source (recombinant) | Organism: Escherichia coli BL21(DE3) (bacteria) |
Buffer solution | pH: 7.4 Details: 20 mM Tris-HCl, pH 7.4, 150 mM NaCl and 5 mM 2-mercaptoethanol |
Specimen | Conc.: 2 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Specimen support | Grid material: COPPER / Grid mesh size: 400 divisions/in. / Grid type: C-flat-1.2/1.3 |
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE-PROPANE / Humidity: 100 % / Chamber temperature: 277 K / Details: blot force |
-Electron microscopy imaging
Microscopy | Model: FEI TITAN |
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Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
Electron lens | Mode: BRIGHT FIELDBright-field microscopy / Nominal defocus max: 2800 nm / Nominal defocus min: 1500 nm / Cs: 2.7 mm / Alignment procedure: COMA FREE |
Specimen holder | Cryogen: NITROGEN Specimen holder model: GATAN 626 SINGLE TILT LIQUID NITROGEN CRYO TRANSFER HOLDER |
Image recording | Electron dose: 40 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Num. of grids imaged: 1 / Num. of real images: 1276 |
Image scans | Width: 3838 / Height: 3710 / Movie frames/image: 30 |
-Processing
Software | Name: PHENIX / Version: 1.19_4080: / Classification: refinement | ||||||||||||||||||||||||||||||||
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EM software |
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Image processing | Details: Images were saved in counting mode using leginon software, and subsequently processed in RELION. | ||||||||||||||||||||||||||||||||
CTF correction | Details: CTFFind4 implemented within RELION/3.0, CTFRefine was also performed after initial reconstruction was achieved. Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 86124 Details: 1000 particles were manually selected from random micrographs. 2D classification was performed on these 1000 particles, and 2D classes were used for relion auto picking | ||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: I (icosahedral) | ||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 3.3 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 38952 / Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||
Atomic model building | B value: 38 / Protocol: FLEXIBLE FIT | ||||||||||||||||||||||||||||||||
Atomic model building | PDB-ID: 3DKT Pdb chain-ID: A / Accession code: 3DKT / Source name: PDB / Type: experimental model | ||||||||||||||||||||||||||||||||
Refine LS restraints |
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