A sphingoglycolipid, also called a glycosphingolipid, is a glycolipid whose lipid portion has a sphingoid backbone. A common arrangement is a carbohydrate headgroup linked to a ceramide, which contains a long-chain amino alcohol and an amide-linked fatty acid. The sugar portion and lipid portion can vary independently, so a class name does not usually specify one unique molecular formula.[ref]
Nomenclature of Lipids by the IUPAC-IUB Commission on Biochemical Nomenclature. Lip-3, General Considerations and generic/individual glycolipid names
Glucosylceramide is a useful example: one glucose residue forms the headgroup, while the ceramide supplies the hydrophobic portion. Changing the sugar headgroup changes the exposed carbohydrate structure; changing the fatty acid chain changes the lipid portion. Two samples described as glucosylceramide can therefore differ in their detailed chain composition.[ref]
Nomenclature of Lipids by the IUPAC-IUB Commission on Biochemical Nomenclature. Lip-3: glucosylceramide example and heterogeneity of fatty acids/long-chain bases
These molecules are also experimentally useful markers. The1990 study proposing Sphingomonas combined cellular sphingoglycolipid observations with 16S ribosomal RNA comparisons and ubiquinone composition. Agreement between chemical and sequence observations supported the taxonomic proposal; a lipid measurement was one part of the evidence, rather than a substitute for all other comparisons.[ref]
Sphingomonas genus and species proposals by E. Yabuuchi and others. Primary Abstract: three lines of evidence for the proposed genus
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