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Open data
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Basic information
Entry | Database: PDB / ID: 6r7l | ||||||||||||
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Title | Ribosome-bound SecYEG translocon in a nanodisc | ||||||||||||
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![]() | MEMBRANE PROTEIN / monomeric translocon / nanodisc / insertion intermediate | ||||||||||||
Function / homology | ![]() protein insertion into membrane from inner side / cell envelope Sec protein transport complex / protein transport by the Sec complex / intracellular protein transmembrane transport / protein-transporting ATPase activity / SRP-dependent cotranslational protein targeting to membrane, translocation / signal sequence binding / protein transmembrane transporter activity / protein secretion / protein targeting ...protein insertion into membrane from inner side / cell envelope Sec protein transport complex / protein transport by the Sec complex / intracellular protein transmembrane transport / protein-transporting ATPase activity / SRP-dependent cotranslational protein targeting to membrane, translocation / signal sequence binding / protein transmembrane transporter activity / protein secretion / protein targeting / intracellular protein transport / membrane => GO:0016020 / membrane / plasma membrane Similarity search - Function | ||||||||||||
Biological species | ![]() ![]() | ||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 6 Å | ||||||||||||
![]() | Kater, L. / Beckmann, R. / Kedrov, A. | ||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Partially inserted nascent chain unzips the lateral gate of the Sec translocon. Authors: Lukas Kater / Benedikt Frieg / Otto Berninghausen / Holger Gohlke / Roland Beckmann / Alexej Kedrov / ![]() Abstract: The Sec translocon provides the lipid bilayer entry for ribosome-bound nascent chains and thus facilitates membrane protein biogenesis. Despite the appreciated role of the native environment in the ...The Sec translocon provides the lipid bilayer entry for ribosome-bound nascent chains and thus facilitates membrane protein biogenesis. Despite the appreciated role of the native environment in the translocon:ribosome assembly, structural information on the complex in the lipid membrane is scarce. Here, we present a cryo-electron microscopy-based structure of bacterial translocon SecYEG in lipid nanodiscs and elucidate an early intermediate state upon insertion of the FtsQ anchor domain. Insertion of the short nascent chain causes initial displacements within the lateral gate of the translocon, where α-helices 2b, 7, and 8 tilt within the membrane core to "unzip" the gate at the cytoplasmic side. Molecular dynamics simulations demonstrate that the conformational change is reversed in the absence of the ribosome, and suggest that the accessory α-helices of SecE subunit modulate the lateral gate conformation. Site-specific cross-linking validates that the FtsQ nascent chain passes the lateral gate upon insertion. The structure and the biochemical data suggest that the partially inserted nascent chain remains highly flexible until it acquires the transmembrane topology. | ||||||||||||
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 | ![]() | 83.2 KB | Display | ![]() |
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PDB format | ![]() | 54 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 4743MC 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/peptide | Mass: 1890.321 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() ![]() |
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#2: Protein | Mass: 10880.122 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() ![]() |
#3: Protein | Mass: 48553.375 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() ![]() |
-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: Stalled E. coli ribosome nascent chain complex (RNC) bound to the translocon SecYEG in a nanodisc Type: COMPLEX / Entity ID: all / Source: NATURAL |
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Molecular weight | Experimental value: NO |
Source (natural) | Organism: ![]() ![]() |
Buffer solution | pH: 7.4 |
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD |
Image recording | Electron dose: 2.5 e/Å2 / Detector mode: INTEGRATING / Film or detector model: FEI FALCON II (4k x 4k) / Num. of real images: 13098 |
Image scans | Width: 4096 / Height: 4096 |
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Processing
EM software |
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CTF correction | Type: NONE | ||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 837184 | ||||||||||||||||||||||||||||
Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||||||
3D reconstruction | Resolution: 6 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 112366 / Algorithm: FOURIER SPACE / Symmetry type: POINT |