6EZN

Cryo-EM structure of the yeast oligosaccharyltransferase (OST) complex

Summary for 6EZN

• Entry DOI: 10.2210/pdb6ezn/pdb
• Related: 6EZN
• EMDB information: 4161 4257
• Descriptor: Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 1, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, alpha-D-mannopyranose-(1-2)-alpha-D-mannopyranose-(1-2)-alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-3)-alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (14 entities in total)
• Functional Keywords: ost complex, oligosaccharyltransferase, n-linked glycosylation, yeast, membrane protein
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast); More
• Total number of polymer chains: 8
• Total formula weight: 291410.84

Authors

Wild, R.,Kowal, J.,Eyring, J.,Ngwa, E.M.,Aebi, M.,Locher, K.P. (deposition date: 2017-11-16, release date: 2018-01-17, Last modification date: 2024-12-11)

Primary citation

Wild, R.,Kowal, J.,Eyring, J.,Ngwa, E.M.,Aebi, M.,Locher, K.P.
Structure of the yeast oligosaccharyltransferase complex gives insight into eukaryotic N-glycosylation.
Science, 359:545-550, 2018

PubMed Abstract: Oligosaccharyltransferase (OST) is an essential membrane protein complex in the endoplasmic reticulum, where it transfers an oligosaccharide from a dolichol-pyrophosphate-activated donor to glycosylation sites of secretory proteins. Here we describe the atomic structure of yeast OST determined by cryo-electron microscopy, revealing a conserved subunit arrangement. The active site of the catalytic STT3 subunit points away from the center of the complex, allowing unhindered access to substrates. The dolichol-pyrophosphate moiety binds to a lipid-exposed groove of STT3, whereas two noncatalytic subunits and an ordered N-glycan form a membrane-proximal pocket for the oligosaccharide. The acceptor polypeptide site faces an oxidoreductase domain in stand-alone OST complexes or is immediately adjacent to the translocon, suggesting how eukaryotic OSTs efficiently glycosylate a large number of polypeptides before their folding.

PubMed: 29301962
DOI: 10.1126/science.aar5140

Experimental method

ELECTRON MICROSCOPY (3.3 Å)