7AFT image
Entry Detail
PDB ID:
7AFT
EMDB ID:
Title:
Cryo-EM structure of the signal sequence-engaged post-translational Sec translocon
Biological Source:
PDB Version:
Deposition Date:
2020-09-20
Release Date:
2020-12-02
Method Details:
Experimental Method:
Resolution:
4.00 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Protein transport protein SEC61
Chain IDs:A
Chain Length:480
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Polymer Type:polypeptide(L)
Description:Protein transport protein SBH1
Chain IDs:B
Chain Length:82
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Polymer Type:polypeptide(L)
Description:Protein transport protein SSS1
Chain IDs:C
Chain Length:80
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Polymer Type:polypeptide(L)
Description:Protein translocation protein SEC63
Chain IDs:D
Chain Length:663
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Polymer Type:polypeptide(L)
Description:Translocation protein SEC66
Chain IDs:E
Chain Length:206
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Polymer Type:polypeptide(L)
Description:Translocation protein SEC72
Chain IDs:F
Chain Length:193
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Polymer Type:polypeptide(L)
Description:Translocation protein SEC62,Translocation protein SEC62
Chain IDs:G
Chain Length:324
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Polymer Type:polypeptide(L)
Description:Mating factor alpha-1,Mating factor alpha-1
Chain IDs:H
Chain Length:178
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Ligand Molecules
Primary Citation
Architecture of the active post-translational Sec translocon.
Embo J. 40 e105643 e105643 (2021)
PMID: 33305433 DOI: 10.15252/embj.2020105643

Abstact

In eukaryotes, most secretory and membrane proteins are targeted by an N-terminal signal sequence to the endoplasmic reticulum, where the trimeric Sec61 complex serves as protein-conducting channel (PCC). In the post-translational mode, fully synthesized proteins are recognized by a specialized channel additionally containing the Sec62, Sec63, Sec71, and Sec72 subunits. Recent structures of this Sec complex in the idle state revealed the overall architecture in a pre-opened state. Here, we present a cryo-EM structure of the yeast Sec complex bound to a substrate, and a crystal structure of the Sec62 cytosolic domain. The signal sequence is inserted into the lateral gate of Sec61α similar to previous structures, yet, with the gate adopting an even more open conformation. The signal sequence is flanked by two Sec62 transmembrane helices, the cytoplasmic N-terminal domain of Sec62 is more rigidly positioned, and the plug domain is relocated. We crystallized the Sec62 domain and mapped its interaction with the C-terminus of Sec63. Together, we obtained a near-complete and integrated model of the active Sec complex.

Legend

Protein

Chemical

Disease

Primary Citation of related structures