Isolation and structural characterization of low‐molecular‐mass monosialyl oligosaccharides derived from respiratory‐mucus glycoproteins of a patient suffering from bronchiectasis

Abstract

The carbohydrate chains of the respiratory‐mucus glycoproteins of a patient suffering from bronchiectasis due to Kartagener's syndrome were released by alkaline borohydride treatment. Low‐molecular‐mass, monosialyl oligosaccharide‐alditols were isolated by anion‐exchange chromatography and fractionated by consecutive straight‐phase high‐performance liquid chromatography (HPLC) on a silica‐based alkylamine column, and reverse‐phase HPLC on a silica‐based octadecyl column, respectively. The structures of the oligosaccharide‐alditols were determined by 500‐MHz 1 H‐NMR spectroscopy in combination with sugar composition analysis. The 24 structures established range in size from disaccharides to heptasaccharides. Novel oligosaccharides obtained from the bronchiectasis mucus glycoproteins are: image image image image image 23 of the 24 monosialyl oligosaccharides characterized can be conceived of as extensions of neutral oligosaccharides purified from the bronchial mucus of this patient [Klein, A. et al. (1988) Eur. J. Biochem. 171 , 631‐642; Breg, J. et al. (1988) Eur. J Biochem. 171 , 643‐654]. The sialic acid residue was found to occur either in α(2→3)‐ or α(2→6)‐linkage to a galactosyl residue or in a(2→6)‐linkage to GalNAc‐0l.