Functional groups of sialic acids involved in binding to siglecs (sialoadhesins) deduced from interactions with synthetic analogues

摘要: The siglecs, formerly called sialoadhesins, are a family of I-type lectins binding to sialic acids on the cell surface. Five members this have been identified: sialoadhesin, myelin-associated glycoprotein (MAG), Schwann myelin protein (SMP), CD22 and CD33. We investigated relevance substituents at position C-9 in N-acetyl group N-acetylneuraminic acid, using series synthetic sialic-acid analogues either resialylated human erythrocytes or as free A-glycosides hapten inhibition. All five siglecs require hydroxy for binding, suggesting hydrogen bonding substituent with site. Remarkable differences were found among proteins their specificity modifications group. Whereas MAG SMP do not tolerate N-glycolylneuraminic they bind halogenated acetyl residues. In case MAG, N-fluoroacetylneuraminic acid is bound about 17-fold better than acid. contrast, murine both show good affinity but only compounds. conclusion, our data indicate that interactions 9 N-acyl contribute significantly strength.