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Science. 2018 Apr 13;360(6385):215-219. doi: 10.1126/science.aar7899. Epub 2018 Mar 8.

Structural basis for coupling protein transport and N-glycosylation at the mammalian endoplasmic reticulum.

Author information

1
Department of Biochemistry, Gene Center and Center for Integrated Protein Science Munich, University of Munich, 81377 Munich, Germany.
2
Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. beckmann@genzentrum.lmu.de pfeffer@biochem.mpg.de f.g.forster@uu.nl.
3
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
4
Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, Netherlands. beckmann@genzentrum.lmu.de pfeffer@biochem.mpg.de f.g.forster@uu.nl.
5
Department of Biochemistry, Gene Center and Center for Integrated Protein Science Munich, University of Munich, 81377 Munich, Germany. beckmann@genzentrum.lmu.de pfeffer@biochem.mpg.de f.g.forster@uu.nl.

Abstract

Protein synthesis, transport, and N-glycosylation are coupled at the mammalian endoplasmic reticulum by complex formation of a ribosome, the Sec61 protein-conducting channel, and oligosaccharyltransferase (OST). Here we used different cryo-electron microscopy approaches to determine structures of native and solubilized ribosome-Sec61-OST complexes. A molecular model for the catalytic OST subunit STT3A (staurosporine and temperature sensitive 3A) revealed how it is integrated into the OST and how STT3-paralog specificity for translocon-associated OST is achieved. The OST subunit DC2 was placed at the interface between Sec61 and STT3A, where it acts as a versatile module for recruitment of STT3A-containing OST to the ribosome-Sec61 complex. This detailed structural view on the molecular architecture of the cotranslational machinery for N-glycosylation provides the basis for a mechanistic understanding of glycoprotein biogenesis at the endoplasmic reticulum.

PMID:
29519914
PMCID:
PMC6319373
[Available on 2019-04-13]
DOI:
10.1126/science.aar7899
[Indexed for MEDLINE]

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