Structure of the yeast oligosaccharyltransferase complex gives insight into eukaryotic N-glycosylation.
Wild, R., Kowal, J., Eyring, J., Ngwa, E.M., Aebi, M., Locher, K.P.(2018) Science 359: 545-550
- PubMed: 29301962
- DOI: https://doi.org/10.1126/science.aar5140
- Primary Citation of Related Structures:
6EZN - 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.
Organizational Affiliation:
Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.