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Open data
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Basic information
Entry | Database: EMDB / ID: EMD-2750 | |||||||||
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Title | Structure of the CsgG-CsgE complex | |||||||||
![]() | reconstruction of the CsgG-CsgE complex | |||||||||
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![]() | Bacterial secretion / membrane protein | |||||||||
Function / homology | ![]() : / curli secretion complex / curli assembly / protein secretion by the type VIII secretion system / protein transmembrane transport / single-species biofilm formation / cell outer membrane / outer membrane-bounded periplasmic space / identical protein binding / plasma membrane Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 24.0 Å | |||||||||
![]() | Krasteva PV / Gubellini F / Remaut H / Fronzes R | |||||||||
![]() | ![]() Title: Structural and mechanistic insights into the bacterial amyloid secretion channel CsgG. Authors: Parveen Goyal / Petya V Krasteva / Nani Van Gerven / Francesca Gubellini / Imke Van den Broeck / Anastassia Troupiotis-Tsaïlaki / Wim Jonckheere / Gérard Péhau-Arnaudet / Jerome S Pinkner ...Authors: Parveen Goyal / Petya V Krasteva / Nani Van Gerven / Francesca Gubellini / Imke Van den Broeck / Anastassia Troupiotis-Tsaïlaki / Wim Jonckheere / Gérard Péhau-Arnaudet / Jerome S Pinkner / Matthew R Chapman / Scott J Hultgren / Stefan Howorka / Rémi Fronzes / Han Remaut / ![]() ![]() ![]() ![]() Abstract: Curli are functional amyloid fibres that constitute the major protein component of the extracellular matrix in pellicle biofilms formed by Bacteroidetes and Proteobacteria (predominantly of the α ...Curli are functional amyloid fibres that constitute the major protein component of the extracellular matrix in pellicle biofilms formed by Bacteroidetes and Proteobacteria (predominantly of the α and γ classes). They provide a fitness advantage in pathogenic strains and induce a strong pro-inflammatory response during bacteraemia. Curli formation requires a dedicated protein secretion machinery comprising the outer membrane lipoprotein CsgG and two soluble accessory proteins, CsgE and CsgF. Here we report the X-ray structure of Escherichia coli CsgG in a non-lipidated, soluble form as well as in its native membrane-extracted conformation. CsgG forms an oligomeric transport complex composed of nine anticodon-binding-domain-like units that give rise to a 36-stranded β-barrel that traverses the bilayer and is connected to a cage-like vestibule in the periplasm. The transmembrane and periplasmic domains are separated by a 0.9-nm channel constriction composed of three stacked concentric phenylalanine, asparagine and tyrosine rings that may guide the extended polypeptide substrate through the secretion pore. The specificity factor CsgE forms a nonameric adaptor that binds and closes off the periplasmic face of the secretion channel, creating a 24,000 Å(3) pre-constriction chamber. Our structural, functional and electrophysiological analyses imply that CsgG is an ungated, non-selective protein secretion channel that is expected to employ a diffusion-based, entropy-driven transport mechanism. | |||||||||
History |
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Structure visualization
Movie |
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Structure viewer | EM map: ![]() ![]() ![]() |
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 790.7 KB | ![]() | |
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Header (meta data) | ![]() ![]() | 11.9 KB 11.9 KB | Display Display | ![]() |
Images | ![]() | 70.9 KB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Validation report
Summary document | ![]() | 185.6 KB | Display | ![]() |
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Full document | ![]() | 184.7 KB | Display | |
Data in XML | ![]() | 5.7 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
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Annotation | reconstruction of the CsgG-CsgE complex | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.99 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
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Sample components
-Entire : CsgG-CsgE complex
Entire | Name: CsgG-CsgE complex |
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Components |
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-Supramolecule #1000: CsgG-CsgE complex
Supramolecule | Name: CsgG-CsgE complex / type: sample / ID: 1000 Details: The sample was reconstituted from purified components in vitro. Oligomeric state: One nonamer of CsgG bound to one nonamer of CsgE Number unique components: 2 |
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Molecular weight | Theoretical: 400 KDa |
-Macromolecule #1: CsgG
Macromolecule | Name: CsgG / type: protein_or_peptide / ID: 1 Name.synonym: Curli production assembly/transport component CsgG Details: Strep-tagged / Number of copies: 9 / Oligomeric state: nonamer / Recombinant expression: Yes |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 290 KDa |
Recombinant expression | Organism: ![]() ![]() |
Sequence | UniProtKB: Curli production assembly/transport component CsgG GO: GO: 0022610, single-species biofilm formation, protein transmembrane transport, cell outer membrane InterPro: Curli production assembly/transport component CsgG |
-Macromolecule #2: CsgE
Macromolecule | Name: CsgE / type: protein_or_peptide / ID: 2 Name.synonym: Curli production assembly/transport component CsgE Details: Poly-histidine tagged. Used for CsgE-CsgG complex reconstitution and pull-down on Talon metal affinity resin. Number of copies: 9 / Oligomeric state: nonamer / Recombinant expression: Yes |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 110 KDa |
Recombinant expression | Organism: ![]() ![]() |
Sequence | UniProtKB: Curli production assembly/transport component CsgE GO: GO: 0022610, single-species biofilm formation, protein transmembrane transport, cell outer membrane InterPro: Curli assembly protein CsgE |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Concentration | 0.05 mg/mL |
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Buffer | pH: 8 Details: 20 mM Tris-HCl pH 8.0, 100 mM NaCl, 100 mM imidazole, 2.5% xylitol, 0.2 mM DTT |
Grid | Details: Quantifoil R2/2 carbon coated grids (Quantifoil Micro Tools GmbH) |
Vitrification | Cryogen name: ETHANE / Chamber humidity: 80 % / Chamber temperature: 92 K / Instrument: LEICA EM GP / Method: Blot for 0.5 seconds before plunging |
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Electron microscopy
Microscope | FEI TECNAI F20 |
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Temperature | Average: 95 K |
Alignment procedure | Legacy - Astigmatism: Astigmatism was checked during imaging and during CTF correction of the micrographs. Micrographs is astigmatism >10% were discarded. |
Date | Jun 2, 2014 |
Image recording | Category: CCD / Film or detector model: FEI FALCON II (4k x 4k) / Number real images: 75 / Average electron dose: 20 e/Å2 |
Electron beam | Acceleration voltage: 200 kV / Electron source: ![]() |
Electron optics | Calibrated magnification: 70350 / Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2 mm / Nominal defocus max: 3.0 µm / Nominal defocus min: 1.0 µm / Nominal magnification: 50000 |
Sample stage | Specimen holder model: GATAN LIQUID NITROGEN |
Experimental equipment | ![]() Model: Tecnai F20 / Image courtesy: FEI Company |
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Image processing
Details | Particles were automatically selected from CTF-corrected micrographs using BOXER (EMAN2). |
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CTF correction | Details: Each micrograph |
Final reconstruction | Applied symmetry - Point group: C9 (9 fold cyclic) / Algorithm: OTHER / Resolution.type: BY AUTHOR / Resolution: 24.0 Å / Resolution method: OTHER / Software - Name: IMAGIC / Number images used: 1221 |
Final two d classification | Number classes: 125 |