EMD-8000
RNC-SRP-SR complex early state
EMD-8000
Single-particle3.7 Å
Deposition: 24/11/2015
Map released: 27/01/2016
Last modified: 16/10/2024
Sample Organism:
Escherichia coli
Sample: Ribosome nascent chain complex with srp-sr in the early state
Fitted models: 5gad (Avg. Q-score: 0.371)
Deposition Authors: Jomaa A , Boehringer D
Sample: Ribosome nascent chain complex with srp-sr in the early state
Fitted models: 5gad (Avg. Q-score: 0.371)
Deposition Authors: Jomaa A , Boehringer D
Structures of the E. coli translating ribosome with SRP and its receptor and with the translocon.
Abstract:
Co-translational protein targeting to membranes is a universally conserved process. Central steps include cargo recognition by the signal recognition particle and handover to the Sec translocon. Here we present snapshots of key co-translational-targeting complexes solved by cryo-electron microscopy at near-atomic resolution, establishing the molecular contacts between the Escherichia coli translating ribosome, the signal recognition particle and the translocon. Our results reveal the conformational changes that regulate the latching of the signal sequence, the release of the heterodimeric domains of the signal recognition particle and its receptor, and the handover of the signal sequence to the translocon. We also observe that the signal recognition particle and the translocon insert-specific structural elements into the ribosomal tunnel to remodel it, possibly to sense nascent chains. Our work provides structural evidence for a conformational state of the signal recognition particle and its receptor primed for translocon binding to the ribosome-nascent chain complex.
Co-translational protein targeting to membranes is a universally conserved process. Central steps include cargo recognition by the signal recognition particle and handover to the Sec translocon. Here we present snapshots of key co-translational-targeting complexes solved by cryo-electron microscopy at near-atomic resolution, establishing the molecular contacts between the Escherichia coli translating ribosome, the signal recognition particle and the translocon. Our results reveal the conformational changes that regulate the latching of the signal sequence, the release of the heterodimeric domains of the signal recognition particle and its receptor, and the handover of the signal sequence to the translocon. We also observe that the signal recognition particle and the translocon insert-specific structural elements into the ribosomal tunnel to remodel it, possibly to sense nascent chains. Our work provides structural evidence for a conformational state of the signal recognition particle and its receptor primed for translocon binding to the ribosome-nascent chain complex.