Synthesis of a photoreactive, radiolabelled derivative of the oligosaccharide of GM1 ganglioside.
A photoreactive, radioiodinatable derivative of the oligosaccharide (GM1OS) of ganglioside GM1 was synthesized as follows: GM1OS was generated from GM1 by ozonolysis and alkaline fragmentation, and reductively aminated to GM1OSNH2 (1-amino-1-deoxymonosialogangliotetraitol). The latter compound was then reacted with N-hydroxysuccinimidyl-4-azidosalicylic acid (NHS-ASA) to form GM1OSNH-ASA [1-(4-azidosalicoylamido)-1-deoxymonosialogangliotetraitol], which was radioiodinated and further purified. To test the [125I]GM1OSNH-IASA [1-(4-iodoazidosalicoylamido)-1-deoxymonosialogangliotetraitol+ ++] as a probe for ganglioside-binding proteins, the derivative was incubated with cholera toxin, which specifically binds GM1, followed by photolysis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The probe only labelled the B or binding subunit of cholera toxin, but not the A or adenylyl cyclase activating subunit. Labelling was inhibited by excess GM1OS, but not by the oligosaccharides from gangliosides GD1a and GD1b. [125I]GM1OSNH-IASA and analogous oligosaccharide derivatives may be valuable probes for detecting ganglioside-binding proteins.
Pacuszka
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Membrane Biochemistry Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
Fishman
P H
PH
D000345:Affinity Labels; D002240:Carbohydrate Sequence; D002772:Cholera Toxin; D005677:G(M1) Ganglioside / Q000138:chemical synthesis* / Q000737:chemistry; D007457:Iodine Radioisotopes; D015335:Molecular Probes / Q000138:chemical synthesis / Q000737:chemistry; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry
D000345:Affinity Labels; D007457:Iodine Radioisotopes; D015335:Molecular Probes; D009844:Oligosaccharides; D005677:G(M1) Ganglioside; D002772:Cholera Toxin