These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Thermodynamic analysis of ligand binding to winged bean (Psophocarpus tetragonolobus) acidic agglutinin reveals its specificity for terminally monofucosylated H-reactive sugars.
    Author: Acharya S, Patanjali SR, Sajjan SU, Gopalakrishnan B, Surolia A.
    Journal: J Biol Chem; 1990 Jul 15; 265(20):11586-94. PubMed ID: 2365687.
    Abstract:
    The sugar-specific binding of N-dansylgalactosamine to WBA II (n = 2; Ka = 5.6 x 10(3) M-1; delta H = -21 kJ.mol-1; delta S = -21.3 J.mol-1.K-1) was utilized in substitution titrations for evaluating the association constants for the interaction of sugars with the lectin. An axial hydroxyl at C-4 and equatorial hydroxyls at C-3 and C-6 as in D-galacto configuration are crucial for binding. Both axial and equatorial hydroxyls are tolerated at C-2. Conformationally akin disaccharides such as lactose, N-acetyllactosamine, Gal beta 1-3GlcNAc, and Gal beta 1-3GalNAc show similar affinities. 2'-Fucosyllactose and H-disaccharide display 146 and 13 times stronger affinity over lactose and galactose, yet fucose by itself is devoid of activity. An interesting feature, noted for the first time, in protein-sugar interactions is the positive entropy change for the binding of 2'-fucosyllactose, suggesting that nonpolar interactions play an important role in stabilization of the lectin-sugar complex. 3-Fucosyllactose, lactodifucotetraose, lacto-N-fucopentaose II and III are inactive, whereas lacto-N-fucopentaose I has 14-fold lower affinity as compared with 2'-fucosyllactose. Conformational analysis indicates that the substitution at subterminal glucose or GlcNAc by L-fucose in either alpha 1-3 or alpha 1-4 linkage leads to its projection so as to sterically hinder the access of 3'-fucosyllactose, lactodifucotetraose, and lacto-N-fucopentaose II and III to the binding site of winged bean agglutinin II. Similarly the projection of alpha 1-3 linked Gal/GalNAc also leads to steric hindrance and hence prevents the binding of blood group A and B reactive sugars. Considering its unique specificity winged bean agglutinin II should be useful in the isolation and characterization of terminally monofucosylated H-reactive oligosaccharides from those that are difucosylated or internally fucosylated.
    [Abstract] [Full Text] [Related] [New Search]