This entry consists of the oligosaccharyl transferase STT3 subunit and related proteins. The STT3 subunit is part of the oligosaccharyl transferase (OTase) complex of proteins and is required for its activity [2]. In eukaryotes, OTase transfers a lipid-linked core-oligosaccharide to selected asparagine residues in the ER [2]. In the archaea STT3 occurs alone, rather than in an OTase complex, and is required for N-glycosylation of asparagines [3-4]. This entry represents the N-terminal domain, consisting of transmembrane helices.

1: Molecular cloning of a highly conserved mouse and human integral membrane protein (Itm1) and genetic mapping to mouse chromosome 9. Hong G, Deleersnijder W, Kozak CA, Van Marck E, Tylzanowski P, Merregaert J; Genomics 1996;31:295-300. PMID:8838310

2: STT3, a highly conserved protein required for yeast oligosaccharyl transferase activity in vivo. Zufferey R, Knauer R, Burda P, Stagljar I, te Heesen S, Lehle L, Aebi M; EMBO J 1995;14:4949-4960. PMID:7588624

3: Haloferax volcanii AglB and AglD are involved in N-glycosylation of the S-layer glycoprotein and proper assembly of the surface layer. Abu-Qarn M, Yurist-Doutsch S, Giordano A, Trauner A, Morris HR, Hitchen P, Medalia O, Dell A, Eichler J; J Mol Biol. 2007;374:1224-1236. PMID:17996897

4: Structure-guided identification of a new catalytic motif of oligosaccharyltransferase. Igura M, Maita N, Kamishikiryo J, Yamada M, Obita T, Maenaka K, Kohda D; EMBO J. 2008;27:234-243. PMID:18046457