Identification and Structural Elucidation of Lectin-Binding Oligosaccharides by Bioaffinity Matrix-Assisted Laser Desorption/lonization Fourier Transform Mass Spectrometry

Cortical granule lectin (CGL) is released by the egg of the South African toad-Xenopus laevis upon fertilization. The lectin binds to oligosaccharides in the extracellular matrix of the egg to form a physical block to prevent additional sperm penetration or polyspermy. To identify the oligosaccharides that bind to CGL, the lectin was immobilized on the surface of a matrix-assisted laser desorption/ionization probe. This bioaffinity probe was used to determine oligosaccharides that bind preferentially to CGL. Structural analyses based on collision-induced dissociation was used to determine that oligosaccharides with the sulfate esters at the nonreducing ends preferentially bind to the lectin.