Erythrina cristagalli lectin or agglutinin (ECL/ECA) is affinity purified lectin consists of two subunits with molecular weights of 28,000 and 26,000. ECL binds to carbohydrate structure in membrane and serum glycoproteins of mammalian cells. The shape of the lectin binding domains may resemble cavity type with Galβ1->4GlcNAc as the core binding site with additional one to four sugar subsites and is most complementary to a linear trisaccharide. Some Galβ1-related oligosaccharides are the major structures for lectin binding. Lectin binding activity can be abolition through salic acid substitution. This allows for specificity to fractionate and isolate mammalian glycoproteins.
Cy5, when bound to Erythrina cristagalli (Coral tree) Lectin (ECL/ECA), can show the binding pattern of this lectin in cellular imaging and flow cytometry. The excitation wavelength required for Cy5 to fluoresce is high enough to avoid overlap with most other fluorochromes, making it useful for dual-labeling experiments. Because of this high excitation, there is typically less background from autofluorescence of biological specimens.