Glycans are key structures involved in different biological processes such as cell attachment, migration and invasion. The glycocode information is frequently deciphered by proteins, wellknow as lectins, which recognize specific carbohydrate topology. The ligand carbohydrate conformation recognized by Euphorbia milii lectin (EML) is described in the present work. EML purified by affinity chromatography shown a homogeneous band by SDSPAGE. From competitive assays can be seen that hydroxyl axial position of C4 and the N-acetamido on C2 of GalNAc are critical points involved in EML interaction. In addition, a hydrophobic locus adjacent to GalNAc is an important region on EML binding, clearly evidenced by using pNPâGalNAc as ligand. Direct binding assays of EML revealed a conformational requirement of adjacent structure to GalNAc. Results suggest that the presence of hydroxyl polar residues neighboring to GalNAc on oligosaccharide structure hindrance carbohydrate-EML interaction. These results are in accordance with preferential EML interaction to â-hydrophobic GalNAc derivative on competitive assays. The EML capacity to recognize epithelial tumor cells reveals to be a potential useful tool on the study of over-expressed GalNAc glycoconjugates.
