A Diocleinae type II lectin from Dioclea lasiophylla Mart. Ex Benth seeds specific to α-lactose/GalNAc

A type II lectin, designated as DlyL2, was purified from Dioclea lasiophylla Mart. ex Benth seeds and some of its physicochemical properties determined. The lectin demonstrated specificity for α-lactose and N-acetyl-d-galactosamine and was able to interact with porcine stomach mucin. DlyL2 has 0.78 % carbohydrates in its composition, therefore can be considered a glycoprotein. In addition, its hemagglutinating activity remained stable at a temperature of 90 °C and in a pH range from 5 to 10. Metal chelation treatment did not affect DlyL2 activity suggesting it's not a metalloprotein. Dlyl2 showed an apparent mass of 31 kDa and average molecular mass of 26.371 kDa. Primary structure data could be generated from the partial amino acid sequence of DlyL2, with about 192 residues sequenced by a combination of Edman degradation and tandem mass spectrometry. The lectin is similar to other type II lectins from Diocleinae subtribe, as well as lectins derived from species of more ancient tribes of the Fabaceae family. In addition, DlyL2 exhibited no toxicity to Artemia sp. nauplii. The present study expands the knowledge about the specificity, structural and physicochemical properties of Diocleinae type II lectins.