Structural analysis of 13 neutral oligosaccharide-alditols released by reductive beta-elimination from oviducal mucins of Rana temporaria

Amphibian eggs are always surrounded by an extracellular matrix, named the jelly coat. This is mainly composed of a highly O-glycosylated, mucin-type glycoprotein. This work has consisted of isolating O-linked neutral oligosa ccharides from oviducal mucin of Rana temporaria, with a view to determinin g their primary structure. Hence, these carbohydrate chains have been relea sed by alkaline borohydride treatment leading to stable glycans. The oligos accharide-alditols have been purified by ion-exchange chromatography and se parated by HPLC. The primary structure of 13 of these carbohydrate chains h ave been obtained by 1D/2D H-1-NMR spectroscopy and methylation analyses, i n combination with MALDI-TOF mass spectroscopy. The results confirm what ha s been observed for six other amphibians about the species-specificity of t he carbohydrate moieties and their likely involvement in the species-specif ic gamete recognition.