Lectinochemical characterization of a GalNAc and multi-Galβ1→4GlcNAc reactive Iectin from Wistaria sinensis seeds

Shuh Chyung Song, Yuen Yuen Chen, Anthony Herp, Ming Sung Tsai, Albert M. Wu*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

12 Scopus citations

Abstract

An agglutinin that has high affinity for GalNAcβ1→, was isolated from seeds of Wistaria sinensis by adsorption to immobilized mild acid-treated hog gastric mucin on Sepharose 4B matrix and elution with aqueous 0.2 M lactose. The binding property of this lectin was characterized by quantitative precipitin assay (QPA) and by inhibition of biotinylated lectin-glycan interaction. Of the 37 glycoforms tested by QPA, this agglutinin reacted best with a GalNAcβ1→4 containing glycoprotein (GP) [Tamm-Horsfall Sd(a+) GP]; a Galβ1→4GlcNAc containing GP (human blood group precursor glycoprotein from ovarian cyst fluid and asialo human α1-acid GP) and a GalNAcα1→3GalNAc containing GP (asialo bird nest GP), but poorly or not at all with most sialic acid containing glycoproteins. Among the oligosaccharides tested, GalNAcα1→3GalNAcβ1→3Galα1→4Galβ1≰Glc (Fp) was the most active ligand. It was as active as GalNAc and two to 11 times more active than Tn cluster mixtures, Galβ1→3/4GlcNAc (I/II), GalNAcα1→3(L-Fucα1→2)Gal (A(h)), Galβ1→4Glc (L), Galβ1→3GalNAc (T) and Galα1→3Galα→methyl (B). Of the monosaccharides and their glycosides tested, p-nitrophenyl βGalNAc was the best inhibitor; it was approximately 1.7 and 2.5 times more potent than its corresponding α anomer and GalNAc (or Fp), respectively. GalNAc was 53.3 times more active than Gal. From the present observations, it can be concluded that the Wistaria agglutinin (WSA) binds to the C-3, C-4 and C-6 positions of GalNAc and Gal residues; the N- acetyl group at C-2 enhances its binding dramatically. The combining site of WSA for GalNAc related ligands is most likely of a shallow type, able to recognize both α and β anomers of GalNAc. Gal ligands must be Galβ1→3/4GIcNAc related, in which subterminal β1→3/4 GlcNAc contributes significantly to binding; hydrophobicity is important for binding of the β anomer of Gal. The decreasing order of the affinity of WSA for mammalian structural carbohydrate units is Fp ≥ multi-II > monomeric II ≥ Tn, I and A(h) ≥ E and L > T > Gal.

Original languageEnglish
Pages (from-to)778-788
Number of pages11
JournalEuropean Journal of Biochemistry
Volume266
Issue number3
DOIs
StatePublished - 15 12 1999

Keywords

  • Carbohydrate specificity
  • Glycoprotein binding
  • Lectins
  • Wistaria sinensis

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