Specificity of the binding site of the sialic acid-binding lectin from ovine placenta, deduced from interactions with synthetic analogues

TRONCOSO, MARÍA FERNANDA; IGLESIAS, MARÍA MERCEDES; ISECKE, RAINER; WOLFENSTEIN-TODEL, CARLOTA; BROSSMER, REINHARD

GLYCOCONJUGATE JOURNAL

Springer Science+Business Media B.V., (Kluwer Academic Publishers B.V.)

Lugar: Holanda; Año: 2000 vol. 17 p. 705 - 711

0282-0080

 The specificity of the sialic acid-binding lectin from ovine placenta was examined in detail by haemagglutination inhibition assays applying a panel of 32 synthetic sialic acid analogues. The carboxylic acid group is a prerequisite for the interaction with the lectin, the a-anomer of the methyl glycoside is only a little more effective as an inhibitor than the b-anomer and the most potent inhibitor was 9-deoxy-10-carboxylic acid Neu5Ac, followed by 4-oxo-Neu5Ac. In contrast to the majority of known sialic acid-binding lectins, the N-acetyl group of Neu5Ac is not indispensable for binding, neither is the hydroxyl group at C-9 since substitutions at this carbon atom are well tolerated. Furthermore, all sulfur-containing substituents at C-9 enhanced the affinity of the lectin. This is the first sialic acid-binding lectin found to strongly bind thio derivatives.