Differential contributions of recognition factors of two plant lectins - Amaranthus caudatus lectin and Arachis hypogea agglutinin, reacting with Thornsen-Friedenreich disaccharide (Gal beta 1-3GalNAc alpha 1-Ser/Thr)

作者：Wu Albert M^*; Wu June H; Yang Zhangung; Singh Tanuja; Goldstein Irwin J; Sharon Nathan

来源：Biochimie, 2008, 90(11-12): 1769-1780.

DOI：10.1016/j.biochi.2008.08.001

• Carbohydrate specificities
• Glycoprotein binding
• Plant lectins
• Polyvalency

Previous reports on the carbohydrate specificities of Amaranthus caudatus lectin (ACL) and peanut agglutinin (PNA, Arachis hypogea) indicated that they share the same specificity for the Thomsen-Friedenreich (T(alpha), Gal beta 1-3GalNAc alpha 1-Ser/Thr) glycotope, but differ in monosaccharide binding-GalNAc >> Gal (inactive) for ACL; Gal >> GalNAc (weak) with respect to PNA. However, knowledge of the recognition factors of these lectins was based on studies with a small number monosaccharides and T-related oligosaccharides. In this study, a wider range of interacting factors of ACL and PNA toward known mammalian structural units, natural polyvalent glycotopes and glycans were examined by enzyme-linked lectinosorbent and inhibition assays. The results indicate that the main recognition factors of ACL, GalNAc was the only monosaccharide recognized by ACL as such, its polyvalent forms (poly GalNAc alpha 1-Ser/Thr, Tn in asialo OSM) were not recognized much better. Human blood group precursor disaccharides Gal beta 1-3/4GlcNAc beta (I(beta)/II(beta)) were weak ligands, while their clusters (multiantermary II(beta)) and polyvalent forms were active. The major recognition factors of PNA were a combination of alpha or beta anomers of T disaccharide and their polyvalent complexes. Although I(beta)/II(beta) were weak haptens, their polyvalent forms played a significant role in binding. From the 50% molar inhibition profile, the shape of the ACL combining site appears to be a cavity type and most complementary to a disaccharide of Gal beta 1-3GalNAc (T), while the PNA binding domain is proposed to be Gal beta 1-3GalNAc alpha or beta 1- as the major combining site with an adjoining subsite (partial cavity type) for a disaccharide, and most complementary to the linear tetrasaccharide, Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Glc (T(beta)1-4L, asialo GM(1) sequence). These results should help us understand the differential contributions of polyvalent ligands, glycotopes and subtopes for the interaction with these lectins to binding, and make them useful tools to study glycosciences, glycomarkers and their biological functions.

• 出版日期2008-12
• 单位长春大学