Studies on the binding of wheat germ agglutinin (Triticum vulgaris) to O-glycans.
The binding profile of Triticum vulgaris (WGA, wheat germ) agglutinin to 23 O-glycans (GalNAc alpha1-->Ser/Thr containing glycoproteins, GPs) was quantitated by the precipitin assay and its specific interactions with O-glycans were confirmed by the precipitin inhibition assay. Of the 28 glycoforms tested, six complex O-glycans (hog gastric mucins, one human blood group A active and two precursor cyst GPs) reacted strongly with WGA and completely precipitated the lectin added. All of the other human blood group A active O-glycans and human blood group precursor GPs also reacted well with the lectin and precipitated over two-thirds of the agglutinin used. They reacted 4-50 times stronger than N-glycans (asialo-fetuin and asialo-human alpha1 acid GP). The binding of WGA to O-glycans was inhibited by either p-NO2-phenyl alpha,betaGlcNAc or GalNAc. From these results, it is highly possible that cluster (multivalent) effects through the high density of weak inhibitory determinants on glycans, such as GalNAc alpha1-->Ser/Thr (Tn), GalNAc at the nonreducing terminal, GlcNAc beta1--> at the non-reducing end and/or as an internal residue, play important roles in precipitation, while the GlcNAc beta1-->4GlcNAc disaccharide may play a minor role in the precipitation of mammalian glycan-WGA complexes.
Wu
A M
AM
Glyco-Immunochemistry Research Lab, Institute of Molecular and Cellular Biology, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
Wu
J H
JH
Song
S C
SC
Tsai
M S
MS
Herp
A
A
D002240:Carbohydrate Sequence; D011232:Chemical Precipitation; D006023:Glycoproteins / Q000378:metabolism; D008969:Molecular Sequence Data; D037121:Plant Lectins; D011134:Polysaccharides / Q000378:metabolism*; D014908:Triticum; D014909:Wheat Germ Agglutinins / Q000378:metabolism*
D006023:Glycoproteins; D037121:Plant Lectins; D011134:Polysaccharides; D014909:Wheat Germ Agglutinins; C014420:colominic acid