Structures of sugar chains of ricin D.
The toxic lectin, ricin D, contains mannose, fucose, xylose, and N-acetylglucosamine as sugar components. Sugar chains are linked to Asn-10 of the A-chain, and to Asn-95 and Asn-135 of the B-chain (Funatsu, G. et al. (1978) Agric. Biol. Chem. 42, 501-503; Araki, T. & Funatsu, G. (1985) FEBS Lett. 191, 121-124). Asparagine-linked sugar chains of each glycopeptide from ricin D were liberated by hydrazinolysis followed by N-acetylation. The reducing end residues of the sugar chains were coupled with 2-aminopyridine and the pyridylamino (PA-) derivatives obtained were purified by gel-filtration and reversed-phase HPLC. Eight main PA-sugar chains were obtained from three glycopeptides and the structures of these sugar chains were determined by component analysis, stepwise exoglycosidase digestions, partial acetolysis, and 500 MHz 1H-NMR spectroscopy. The results show that oligomannose type sugar chains (Man6-7GlcNAc2) are linked to Asn-95; Man5-7 GlcNAc2 and M4X (structure, see below) to Asn-135 of the B-chain, and M3FX and M3X to Asn-10 of the A-chain. (Formula: see text).
Kimura
Y
Y
Laboratory of Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka.
Hase
S
S
Kobayashi
Y
Y
Kyogoku
Y
Y
Ikenaka
T
T
Funatsu
G
G
D000107:Acetylation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D006020:Glycopeptides / Q000032:analysis; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000302:isolation & purification; D012276:Ricin / Q000032:analysis*
D006020:Glycopeptides; D009844:Oligosaccharides; D012276:Ricin