Datura stramonium agglutinin or lectin (DSA/DSL) is purified by affinity chromatography. Seeds of Datura stramonium contain at least three different carbohydrate-binding proteins, and the most prominent lectin is a dimeric glycoprotein composed of two nonidentical subunits that contains 40% carbohydrate. It binds well to N-acetylglucosamine, oligomers, and branched pentasaccharide, including two N-acetylglucosamine disaccharides linked to mannose (β-1,6) and (β-1,2), which is known to be the most potent inhibitor of agglutination. DSL prefers binding to (GlcNAc)2-4 and elutes with the sugar chitin hydrolysate. DSL binds well in the acidic pH range and its affinity decreases above pH 8.0. This agglutinin has blood group A, B, and O specificity. Studies have shown that DSA can act as a biomarker for neoplastic urotherial cells.
Cy3 can be used to viualize the binding pattern of Datura stramonium Lectin (DSA/DSL) in cellular imaging and flow cytometry. Cy3 is more photostable than many other flourophores and can be seen with TRITC filter sets. It is commonly combined with green-fluorescent dyes for dual-labeling.