Dolichyl-diphosphooligosaccharide--protein glycosyltransferase 48kDa subunit (IPR005013)

Short name: DDOST_48_kDa_subunit

Overlapping homologous superfamilies


Family relationships



Members of this family are involved in asparagine-linked protein glycosylation. In particular, dolichyl-diphosphooligosaccharide-protein glycosyltransferase (DDOST), also known as oligosaccharyltransferase (EC:, transfers the high-mannose sugar GlcNAc(2)-Man(9)-Glc(3) from a dolichol-linked donor to an asparagine acceptor in a consensus Asn-X-Ser/Thr motif. In most eukaryotes, the DDOST complex is composed of three subunits, which in humans are described as a 48kDa subunit, ribophorin I, and ribophorin II [PMID: 936767]. However, the yeast DDOST appears to consist of six subunits (alpha, beta, gamma, delta, epsilon, zeta). The yeast beta subunit is a 45kDa polypeptide, previously discovered as the Wbp1 protein, with known sequence similarity to the human 48kDa subunit and the other orthologues. This family includes the 48kDa-like subunits from several eukaryotes; it also includes the yeast DDOST beta subunit Wbp1.

Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit Wbp1 is the beta subunit of the OST complex, one of the original six subunits purified [PMID: 8175708]. Wbp1 is essential [PMID: 1724755, PMID: 1600939], but conditional mutants have decreased transferase activity [PMID: 1600939, PMID: 8428586].

GO terms

Biological Process

GO:0018279 protein N-linked glycosylation via asparagine

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0005789 endoplasmic reticulum membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.