The oligosaccharyltransferase complexes (OST) are multi-span ER membrane protein complexes that catalyzes the addition of glycans to selected secretory and membrane protein polypeptides in the ER lumnen. They transfers the dolicholphosphate-linked core oligosaccharide to selected Asn residues within the motif Asn-X-Ser/Thr in a process termed N-glycosylation. The OSTA complex acts on the nascent polypeptide during co-translational ER-translocation. (Adapted from
PMID:31810196.)
