+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-8812 | ||||||||||||
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Title | Structure of the PulG pseudopilus | ||||||||||||
Map data | map of PulG filament | ||||||||||||
Sample |
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Keywords | helical polymer / bacterial secretion / cryo-EM / PROTEIN TRANSPORT | ||||||||||||
Function / homology | Function and homology information protein secretion by the type II secretion system / type II protein secretion system complex / membrane => GO:0016020 / plasma membrane Similarity search - Function | ||||||||||||
Biological species | Klebsiella oxytoca (bacteria) | ||||||||||||
Method | helical reconstruction / cryo EM / Resolution: 5.0 Å | ||||||||||||
Authors | Lopez-Castilla A / Thomassin JL | ||||||||||||
Funding support | United States, France, European Union, 3 items
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Citation | Journal: Nat Microbiol / Year: 2017 Title: Structure of the calcium-dependent type 2 secretion pseudopilus. Authors: Aracelys López-Castilla / Jenny-Lee Thomassin / Benjamin Bardiaux / Weili Zheng / Mangayarkarasi Nivaskumar / Xiong Yu / Michael Nilges / Edward H Egelman / Nadia Izadi-Pruneyre / Olivera Francetic / Abstract: Many Gram-negative bacteria use type 2 secretion systems (T2SSs) to secrete proteins involved in virulence and adaptation. Transport of folded proteins via T2SS nanomachines requires the assembly of ...Many Gram-negative bacteria use type 2 secretion systems (T2SSs) to secrete proteins involved in virulence and adaptation. Transport of folded proteins via T2SS nanomachines requires the assembly of inner membrane-anchored fibres called pseudopili. Although efficient pseudopilus assembly is essential for protein secretion, structure-based functional analyses are required to unravel the mechanistic link between these processes. Here, we report an atomic model for a T2SS pseudopilus from Klebsiella oxytoca, obtained by fitting the NMR structure of its calcium-bound subunit PulG into the ~5-Å-resolution cryo-electron microscopy reconstruction of assembled fibres. This structure reveals the comprehensive network of inter-subunit contacts and unexpected features, including a disordered central region of the PulG helical stem, and highly flexible C-terminal residues on the fibre surface. NMR, mutagenesis and functional analyses highlight the key role of calcium in PulG folding and stability. Fibre disassembly in the absence of calcium provides a basis for pseudopilus length control, essential for protein secretion, and supports the Archimedes screw model for the type 2 secretion mechanism. | ||||||||||||
History |
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-Structure visualization
Movie |
Movie viewer |
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Structure viewer | EM map: SurfViewMolmilJmol/JSmol |
Supplemental images |
-Downloads & links
-EMDB archive
Map data | emd_8812.map.gz | 4.8 MB | EMDB map data format | |
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Header (meta data) | emd-8812-v30.xml emd-8812.xml | 10.6 KB 10.6 KB | Display Display | EMDB header |
Images | emd_8812.png | 110.4 KB | ||
Filedesc metadata | emd-8812.cif.gz | 5.2 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-8812 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-8812 | HTTPS FTP |
-Validation report
Summary document | emd_8812_validation.pdf.gz | 413.6 KB | Display | EMDB validaton report |
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Full document | emd_8812_full_validation.pdf.gz | 413.2 KB | Display | |
Data in XML | emd_8812_validation.xml.gz | 4.4 KB | Display | |
Data in CIF | emd_8812_validation.cif.gz | 5 KB | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-8812 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-8812 | HTTPS FTP |
-Related structure data
Related structure data | 5wdaMC 5o2yC M: atomic model generated by this map C: citing same article (ref.) |
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Similar structure data |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Related items in Molecule of the Month |
-Map
File | Download / File: emd_8812.map.gz / Format: CCP4 / Size: 8.1 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Annotation | map of PulG filament | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Projections & slices | Image control
Images are generated by Spider. generated in cubic-lattice coordinate | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.05 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
-Sample components
-Entire : PulG pseudopilus
Entire | Name: PulG pseudopilus |
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Components |
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-Supramolecule #1: PulG pseudopilus
Supramolecule | Name: PulG pseudopilus / type: organelle_or_cellular_component / ID: 1 / Parent: 0 / Macromolecule list: all |
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Source (natural) | Organism: Klebsiella oxytoca (bacteria) |
-Macromolecule #1: General secretion pathway protein G
Macromolecule | Name: General secretion pathway protein G / type: protein_or_peptide / ID: 1 / Number of copies: 25 / Enantiomer: LEVO |
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Source (natural) | Organism: Klebsiella oxytoca (bacteria) |
Molecular weight | Theoretical: 14.525482 KDa |
Recombinant expression | Organism: Escherichia coli (E. coli) |
Sequence | String: (MEA)TLLEIMVVI VILGVLASLV VPNLMGNKEK ADRQKVVSDL VALEGALDMY KLDNSRYPTT EQGLQALVSA PSAEPH ARN YPEGGYIRRL PQDPWGSDYQ LLSPGQCGQV DIFSLGPDGV PESNDDIGNC TIGKK UniProtKB: Type II secretion system core protein G |
-Macromolecule #2: CALCIUM ION
Macromolecule | Name: CALCIUM ION / type: ligand / ID: 2 / Number of copies: 25 / Formula: CA |
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Molecular weight | Theoretical: 40.078 Da |
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | helical reconstruction |
Aggregation state | filament |
-Sample preparation
Buffer | pH: 7.5 |
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Vitrification | Cryogen name: ETHANE / Instrument: FEI VITROBOT MARK IV |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: FEI FALCON II (4k x 4k) / Detector mode: INTEGRATING / Number grids imaged: 1 / Number real images: 1819 / Average electron dose: 20.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |
-Image processing
Final reconstruction | Applied symmetry - Helical parameters - Δz: 10.2 Å Applied symmetry - Helical parameters - Δ&Phi: 83.2 ° Applied symmetry - Helical parameters - Axial symmetry: C1 (asymmetric) Algorithm: BACK PROJECTION / Resolution.type: BY AUTHOR / Resolution: 5.0 Å / Resolution method: FSC 0.143 CUT-OFF / Software - Name: IHRSR / Number images used: 85619 |
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Startup model | Type of model: OTHER / Details: solid cylinder |
Final angle assignment | Type: NOT APPLICABLE |