The N-oligosaccharyltransferase complex from yeast.
N-Oligosaccharyltransferase catalyzes the N-glycosylation of asparagine residues of nascent polypeptide chains in the endoplasmic reticulum, a pathway highly conserved in all eukaryotes. An enzymatically active complex was isolated from microsomal membranes from Saccharomyces cerevisiae, which is composed of four proteins: Wbp1p and Swp1p (previously found to be encoded by two essential genes necessary for N-glycosylation in vivo and in vitro) and two additional proteins with a molecular mass of 60/62 kDa and 34 kDa. The 60/62 component represents differentially glycosylated forms of a protein that has sequence homology to ribophorin I. Wbp1p and Swp1p reveal homology to mammalian OST 48 and ribophorin II, respectively. Ribophorin I and II and OST 48 were recently shown to be constituents of the mammalian transferase from dog pancreas. The data reveal a high conservation of the organization of this enzyme activity.
Knauer
R
R
Lehrstuhl für Zellbiologie und Pflanzenphysiologie, Universität Regensburg, Germany.
Lehle
L
L
D000595:Amino Acid Sequence; D000818:Animals; D001216:Asparagine / Q000378:metabolism; D004285:Dogs; D006031:Glycosylation; D006602:Hexosyltransferases; D007425:Intracellular Membranes / Q000201:enzymology; D008565:Membrane Proteins / Q000737:chemistry; D008861:Microsomes / Q000201:enzymology / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010179:Pancreas / Q000201:enzymology; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D017385:Sequence Homology; D014166:Transferases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism
D008565:Membrane Proteins; C034241:ribophorin; D001216:Asparagine; D014166:Transferases; D006602:Hexosyltransferases; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase