title: Yeast Wbp1p and Swp1p form a protein complex essential for oligosaccharyl transferase activity.
abstract: Asparagine-linked N-glycosylation is an essential protein modification occurring in all eukaryotic cells. The central step is the co-translational transfer of the core oligosaccharide assembled on the lipid carrier dolichol phosphate to selected Asn-X-Ser/Thr residues of nascent polypeptide chains in the endoplasmic reticulum. This reaction is catalyzed by the enzyme N-oligosaccharyl transferase. In yeast, Wbp1p is an essential component of this enzyme. Using a high copy number suppression approach, the SWP1 gene was isolated as an allele specific suppressor of a wbp1 mutation. Swp1p is a 30 kDa type I transmembrane protein and essential for cell viability. Similar to Wbp1p, depletion of Swp1p results in reduced N-oligosaccharyl transferase activity in vivo and in vitro. Wbp1p and Swp1p can be chemically cross-linked, suggesting that both proteins are essential constituents of the N-oligosaccharyl transferase complex.
authors.affiliation: Institut für Molekularbiologie I, Universität Zürich, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: te Heesen
authors.forename: R
authors.initials: R
authors.lastname: Knauer
authors.forename: L
authors.initials: L
authors.lastname: Lehle
authors.forename: M
authors.initials: M
authors.lastname: Aebi
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D005800:Genes, Fungal; D006602:Hexosyltransferases; D007700:Kinetics; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides; D010641:Phenotype; D010957:Plasmids; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*; D013489:Suppression, Genetic; D013696:Temperature; D014166:Transferases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D014166:Transferases; D006602:Hexosyltransferases; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase