The Fine Structure ofCaenorhabditis elegans N-Glycans

We report the fine structure of a nearly contiguous series ofN-glycans from the soil nematodeCaenorhabditis elegans.Five major classes are revealed including high mannose, mammalian-type complex, hybrid, fuco-pausimannosidic (five mannose residues or fewer substituted with fucose), and phosphocholine oligosaccharides. The high mannose, complex, and hybridN-glycan series show a high degree of conservation with the mammalian biosynthetic pathways. The fuco-pausimannosidic glycans contain a novel terminal fucose substitution of mannose. The phosphocholine oligosaccharides are high mannose type and are multiply substituted with phosphocholine. Although phosphocholine oligosaccharides are known immunomodulators in human nematode and trematode infections,C. elegansis unique as a non-parasitic nematode containing phosphocholineN-glycans. Therefore, studies inC. elegansshould aid in the elucidation of the biosynthetic pathway(s) of this class of biomedically relevant compounds. Results presented here show thatC. eleganshas a functional orthologue for nearly every known enzyme found to be deficient in congenital disorders of glycosylation types I and II. This nematode is well characterized genetically and developmentally. Therefore, elucidation of itsN-glycome, as shown in this report, may place it among the useful systems used to investigate human disorders of glycoconjugate synthesis such as the congenital disorders of glycosylation syndromes.