title: Mapping the interaction of the STT3 subunit of the oligosaccharyl transferase complex with nascent polypeptide chains.
abstract: Many secretory and membrane proteins are N-glycosylated by the oligosaccharyl transferase complex during their translocation across the endoplasmic reticulum membrane. Several experimental observations suggest that the highly conserved STT3 subunit contains the active site of the oligosaccharyl transferase. Here, we report a detailed study of the interaction between the active site of the STT3 protein and nascent polypeptide chains using an in vitro photocrosslinking technique. Our results show that the addition of a glycan moiety in a stretch of approximately 15 residues surrounding a QK(*)T cross-linking site impairs the interaction between the nascent chain and STT3.
authors.affiliation: Department of Medical Biochemistry and Genetics, Texas A&M University System Health Science Center, USA.
authors.forename: Andrey L
authors.initials: AL
authors.lastname: Karamyshev
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Kelleher
authors.forename: Reid
authors.initials: R
authors.lastname: Gilmore
authors.forename: Arthur E
authors.initials: AE
authors.lastname: Johnson
authors.forename: Gunnar
authors.initials: G
authors.lastname: von Heijne
authors.forename: Ingmarie
authors.initials: I
authors.lastname: Nilsson
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003432:Cross-Linking Reagents; D006031:Glycosylation; D006602:Hexosyltransferases / Q000737:chemistry / Q000378:metabolism*; D008027:Light; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D010455:Peptides / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry; D011388:Prolactin / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D010455:Peptides; D011134:Polysaccharides; D011498:Protein Precursors; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C017671:preprolactin; D011388:Prolactin; D006602:Hexosyltransferases; C096554:STT3 protein, S cerevisiae; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase