Structure of the monosialyl oligosaccharides derived from salivary gland mucin glycoproteins of the Chinese swiftlet (genus Collocalia). Characterization of novel types of extended core structure, Gal beta(1----3)[GlcNAc beta(1----6)] GalNAc alpha(1----3)GalNAc(-ol), and of chain termination, [Gal alpha(1----4)]0-1[Gal beta(1----4)]2GlcNAc beta(1----.).
The mucus glycoproteins, the so-called nest-cementing substance, from the salivary gland of Chinese swiftlets (genus Collocalia) are mainly constituted of sialic acid-rich O-glycosylproteins. Alkaline reductive treatment of the crude material led to the release of some neutral and numerous monosialyl and disialyl oligosaccharides. These were fractionated by gel filtration, anion-exchange chromatography, and high-performance liquid chromatography. The structures of the monosialyl oligosaccharides were established by combination of sugar and methylation analysis, fast atom bombardment-mass spectrometry, and electron impact-mass spectrometry after permethylation and 1H NMR spectroscopy (at 500 MHz). Typically, some of the monosialyl oligosaccharides appeared to possess the core structure Gal beta(1----3)[GlcNAc beta(1----6)]GalNAc alpha(1----3)GalNAc-ol. Moreover, the (1----6)-linked branch consisted of an unusual di- or trigalactosyl sequence, [Gal alpha(1----4)0-1Gal beta(1----4)Gal beta (1----4)GlcNAc beta(1----6). Thus, the most complex representatives of the monosialyl fraction from Collocalia mucin were found to be: (Formula: see text) The other compounds identified are partial structures thereof.
D000818:Animals; D001717:Birds / Q000378:metabolism*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009077:Mucins / Q000302:isolation & purification; D009844:Oligosaccharides / Q000302:isolation & purification; D012469:Salivary Glands / Q000378:metabolism*; D012794:Sialic Acids / Q000032:analysis
D009077:Mucins; D009844:Oligosaccharides; D012794:Sialic Acids