iFluor(TM) 488-Wheat Germ Agglutinin (WGA) Conjugate

Wheat germ agglutinin (WGA) is a lectin that binds to N-acetyl-D-glucosamine and sialic acid. It is of the most studied and useful lectins for it biological applications. Since WGA binds to glycoconjugates its derivatives and conjugates are widely used to label cell membranes and fibrotic scar tissue for fluorescence imaging and analysis. The carbohydrate-binding specificity of WGA is directed against sequences of beta-1,4-GlcNAc-linked residues, the chitodextrins. Each monomer contains two identical, non-interacting binding sites which are complementary to 3 or 4 beta-1,4-GlcNAc units. Of the monosaccharides examined, only GlcNAc binds to WGA. ManNAc does not bind and GalNAc binds only weakly. WGA binds with high affinity to internal GlcNAc residues in large oligosaccharides containing repeat sequences of Gal beta(1----4)GlcNAc beta(1----3) (i.e. polylactosamine-type glycans). N-Acetylneuraminic acid is involved only in low-affinity interactions with WGA. WGA displays an intricate pattern of saccharide specificities that might be used for structural analysis of complex carbohydrates. iFluor(TM)488 conjugate of WGA might be the brightest WGA conjugate. It exhibits the bright and green fluorescence of the iFluor(TM) 488 dye. iFluor(TM)488 WGA conjugate binds to sialic acid and N-acetylglucosaminyl residues as AF488 WGA conjugate does.