Structural analysis of 20 oligosaccharide-alditols released from the jelly coat of Rana palustris eggs by reductive beta-elimination characterization of the polymerized sequence [Gal(beta1, 3)GalNAc(alpha1-4)]n.

The eggs of amphibians are surrounded by three to eight layers of jelly coats. This extracellular matrix is mainly composed of hydrated mucin-type glycoproteins. These highly glycosylated molecules are synthesized by oviduct and play an important role in the fertilization process. Recent structural analyses have shown the strict species-specificity of the O-linked oligosaccharides which constitute 60-70% of these oviducal mucins. Consequently, these carbohydrate chains represent new phenotypic markers, and from a biological point of view, can influence parasite tropism or can be involved in species-specific interaction of gametes. The primary structure of 20 oligosaccharide-alditols, released by alkali/borohydride treatment from the mucin of Rana palustris egg jelly coats, was established by 1H and 13C-NMR analysis. Thirteen of these components possess new structures and the polymerization of the sequence Gal(beta1-3)GalNAc(alpha1-4) characterizes the species-specificity of R. palustris.