Griffonia simplicifolia lectin (GSL I) is affinity purified from a woody climbing shrub native to Africa. GSL I is composed of two types of subunits A and B that combine to form tetrameric structures, resulting in five isolectins. This lectin has affinity for terminal α-D-galactosyl residues and terminal N-acetyl-α-D-galactosaminyl residues. The A-rich lectin preferentially agglutinates blood group A erythrocytes and thus appears to be specific for α-N-acetylgalactosamine residues, while the B-rich lectin preferentially agglutinates blood group B cells and is specific for α-galactose residues. This lectin shows specificity for blood group B greater than blood group A1.
GSL I has been reported to bind several glycoproteins including laminin. Since some α-D-galactosyl residues are expressed in endothelial cells of mouse tissues, GSL I can present a highly specific surface of glycosylation pattern in these cells.
Texas Red is a red-fluorescent dye and when bound to Griffonia simplicifolia Lectin (GSL I) can show the binding pattern of this lectin in cellular imaging applications. There is very little overlap between the emission spectra of Texas Red and FITC making this combination ideal for dual-labeling experiments. Rhodamine dyes, such as Texas Red, are more photostable and less sensitive to pH change when compared to other dyes such as fluorescein.