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- PDB-5ldf: Maltose binding protein genetically fused to dodecameric glutamin... -
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Open data
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Basic information
Entry | Database: PDB / ID: 5ldf | |||||||||
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Title | Maltose binding protein genetically fused to dodecameric glutamine synthetase | |||||||||
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![]() | LIGASE / Fusion protein / chimera / dodecamer / symmetrized construct | |||||||||
Function / homology | ![]() nitrogen utilization / glutamine synthetase / glutamine biosynthetic process / glutamine synthetase activity / carbohydrate transmembrane transporter activity / maltose binding / maltose transport / maltodextrin transmembrane transport / ATP-binding cassette (ABC) transporter complex, substrate-binding subunit-containing / outer membrane-bounded periplasmic space ...nitrogen utilization / glutamine synthetase / glutamine biosynthetic process / glutamine synthetase activity / carbohydrate transmembrane transporter activity / maltose binding / maltose transport / maltodextrin transmembrane transport / ATP-binding cassette (ABC) transporter complex, substrate-binding subunit-containing / outer membrane-bounded periplasmic space / ATP binding / metal ion binding / membrane / cytoplasm Similarity search - Function | |||||||||
Biological species | ![]() ![]() ![]() | |||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 6.2 Å | |||||||||
![]() | Coscia, F. / Petosa, C. / Schoehn, G. | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Fusion to a homo-oligomeric scaffold allows cryo-EM analysis of a small protein. Authors: Francesca Coscia / Leandro F Estrozi / Fabienne Hans / Hélène Malet / Marjolaine Noirclerc-Savoye / Guy Schoehn / Carlo Petosa / ![]() Abstract: Recent technical advances have revolutionized the field of cryo-electron microscopy (cryo-EM). However, most monomeric proteins remain too small (<100 kDa) for cryo-EM analysis. To overcome this limitation, we explored a strategy whereby a monomeric target protein is genetically fused to a homo-oligomeric scaffold protein and the junction optimized to allow the target to adopt the scaffold symmetry, thereby generating a chimeric particle suitable for cryo-EM. To demonstrate the concept, we fused maltose-binding protein (MBP), a 40 kDa monomer, to glutamine synthetase, a dodecamer formed by two hexameric rings. Chimeric constructs with different junction lengths were screened by biophysical analysis and negative-stain EM. The optimal construct yielded a cryo-EM reconstruction that revealed the MBP structure at sub-nanometre resolution. These findings illustrate the feasibility of using homo-oligomeric scaffolds to enable cryo-EM analysis of monomeric proteins, paving the way for applying this strategy to challenging structures resistant to crystallographic and NMR analysis. | |||||||||
History |
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Structure visualization
Movie |
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Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 1.6 MB | Display | ![]() |
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PDB format | ![]() | 1.3 MB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 4039MC M: map data used to model this data C: citing same article ( |
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Similar structure data |
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Links
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Assembly
Deposited unit | ![]()
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Components
#1: Protein | Mass: 51586.266 Da / Num. of mol.: 12 / Mutation: Deletion of residues 1-2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() #2: Protein | Mass: 40753.152 Da / Num. of mol.: 12 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() #3: Polysaccharide | alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose / alpha-maltose |
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-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: Maltose-binding protein genetically fused to glutamine synthetase Type: COMPLEX / Entity ID: #1-#2 / Source: RECOMBINANT | |||||||||||||||||||||||||
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Molecular weight | Value: 1.11 MDa / Experimental value: NO | |||||||||||||||||||||||||
Source (natural) | Organism: ![]() ![]() | |||||||||||||||||||||||||
Source (recombinant) | Organism: ![]() ![]() | |||||||||||||||||||||||||
Buffer solution | pH: 8 | |||||||||||||||||||||||||
Buffer component |
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Specimen | Conc.: 0.5 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | |||||||||||||||||||||||||
Specimen support | Grid material: COPPER/RHODIUM / Grid mesh size: 400 divisions/in. / Grid type: Quantifoil | |||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 290 K |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Tecnai F30 / Image courtesy: FEI Company |
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Microscopy | Model: FEI TECNAI F30 / Details: Polara Top entry |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 3500 nm / Nominal defocus min: 1000 nm / Alignment procedure: COMA FREE |
Specimen holder | Cryogen: NITROGEN |
Image recording | Average exposure time: 6 sec. / Electron dose: 25 e/Å2 / Detector mode: SUPER-RESOLUTION / Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Num. of real images: 165 |
Image scans | Movie frames/image: 40 |
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Processing
EM software |
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CTF correction | Type: PHASE FLIPPING ONLY | ||||||||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 39167 | ||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: D6 (2x6 fold dihedral) | ||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 6.2 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 13847 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||
Atomic model building | Protocol: RIGID BODY FIT / Space: REAL |