Molecular basis for glycan recognition and reaction priming of eukaryotic oligosaccharyltransferase.

Ramírez, Ana S; De Capitani, Mario; Pesciullesi, Giorgio; Kowal, Julia; Bloch, Joël S; Irobalieva, Rossitza N; Reymond, Jean-Louis; Aebi, Markus; Locher, Kaspar P (2022). Molecular basis for glycan recognition and reaction priming of eukaryotic oligosaccharyltransferase. Nature communications, 13(1), p. 7296. Nature Publishing Group 10.1038/s41467-022-35067-x

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Oligosaccharyltransferase (OST) is the central enzyme of N-linked protein glycosylation. It catalyzes the transfer of a pre-assembled glycan, GlcNAc2Man9Glc3, from a dolichyl-pyrophosphate donor to acceptor sites in secretory proteins in the lumen of the endoplasmic reticulum. Precise recognition of the fully assembled glycan by OST is essential for the subsequent quality control steps of glycoprotein biosynthesis. However, the molecular basis of the OST-donor glycan interaction is unknown. Here we present cryo-EM structures of S. cerevisiae OST in distinct functional states. Our findings reveal that the terminal glucoses (Glc3) of a chemo-enzymatically generated donor glycan analog bind to a pocket formed by the non-catalytic subunits WBP1 and OST2. We further find that binding either donor or acceptor substrate leads to distinct primed states of OST, where subsequent binding of the other substrate triggers conformational changes required for catalysis. This alternate priming allows OST to efficiently process closely spaced N-glycosylation sites.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

De Capitani, Mario Michele Oreste, Pesciullesi, Giorgio, Reymond, Jean-Louis

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

2041-1723

Publisher:

Nature Publishing Group

Language:

English

Submitter:

Pubmed Import

Date Deposited:

28 Nov 2022 08:58

Last Modified:

05 Dec 2022 16:29

Publisher DOI:

10.1038/s41467-022-35067-x

PubMed ID:

36435935

BORIS DOI:

10.48350/175200

URI:

https://boris.unibe.ch/id/eprint/175200

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