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Publication Abstract from PubMed

N-Glycosylation is an essential and highly conserved protein modification. In eukaryotes, it is catalyzed by a multisubunit membrane-associated enzyme, oligosaccharyltransferase (OT). We report the high resolution structure of the C-terminal domain of eukaryotic Stt3p. Unlike its soluble beta-sheet-rich prokaryotic counterparts, our model reveals that the C-terminal domain of yeast Stt3p is highly helical and has an overall oblate spheroid-shaped structure containing a membrane-embedded region. Anchoring of this protein segment to the endoplasmic reticulum membrane is likely to bring the membrane-embedded donor substrate closer, thus facilitating glycosylation efficiency. Structural comparison of the region near the WWDYG signature motif revealed that the acceptor substrate-binding site of yeast OT strikingly resembles its prokaryotic counterparts, suggesting a conserved mechanism of N-glycosylation from prokaryotes to eukaryotes. Furthermore, comparison of the NMR and cryo-EM structures of yeast OT revealed that the molecular architecture of this acceptor substrate-recognizing domain has interesting spatial specificity for interactions with other essential OT subunits.

Eukaryotic N-Glycosylation Occurs via the Membrane-anchored C-terminal Domain of the Stt3p Subunit of Oligosaccharyltransferase.,Huang C, Bhaskaran R, Mohanty S J Biol Chem. 2012 Sep 21;287(39):32450-8. Epub 2012 Aug 3. PMID:22865878^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.