title: Primary structure of the N-linked carbohydrate chains of Calreticulin from spinach leaves.
abstract: Calreticulin is a multifunctional Ca(2+)-binding protein of the endoplasmic reticulum of most eukaryotic cells. The 56 kDa Calreticulin glycoprotein isolated from spinach (Spinacia oleracea L.) leaves was N-deglycosylated by PNGase-F digestion. The carbohydrate moiety was isolated by gel permeation chromatography and purified by high-pH anion-exchange chromatography. The fractions were investigated by 500 MHz 1H-NMR spectroscopy, in combination with monosaccharide analysis and fast-atom bombardment-mass spectrometry. The following carbohydrate structure could be established as the major component (Man8GlcNAc2): (sequence see text) Heterogeneity was demonstrated by the presence of two minor components being Man7GlcNAc2 lacking a terminal residue (D1 or D3), compared to the major component. A cross-reactivity with an antibody against the endoplasmic reticulum retention signal HDEL was also found.
authors.affiliation: Department of Biology, University of Padova, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Navazio
authors.forename: B
authors.initials: B
authors.lastname: Baldan
authors.forename: P
authors.initials: P
authors.lastname: Mariani
authors.forename: G J
authors.initials: GJ
authors.lastname: Gerwig
authors.forename: J F
authors.initials: JF
authors.lastname: Vliegenthart
mesh_terms: D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000276:immunology; D037282:Calreticulin; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins / Q000032:analysis / Q000737:chemistry; D012261:Ribonucleoproteins / Q000737:chemistry* / Q000276:immunology; D018724:Spinacia oleracea / Q000737:chemistry*
chemical_list: D002135:Calcium-Binding Proteins; D037282:Calreticulin; D002241:Carbohydrates; D010940:Plant Proteins; D012261:Ribonucleoproteins