Lectins act as agonists or antagonists of glycoprotein receptors present in the membranes of blood cells, and on other targets as coagulation factors and essential proteins for hemostasis, due to their ability to recognize carbohydrates. Even though the lectins research is abundant in isolated vegetable and animal tissues, it is reduced compared to the research in venoms.
In snake venom proteomes of Viperidae family, lectins occur in low amounts, however, their participation in hemorrhagic events during envenomation are of clinical importance. In fish venoms, there are some descriptions of karatoxin from H. rubripinnis, plumieribectin from S. plumieri, and nattectina from T. nattereri, which have cytolytic, reduction in cell migration and proinflammatory effects, respectively. Otherwise, in scorpion venoms, some lectins have been found in serum of Mastigoproctus giganteus, hemolymph of Heterometrus granulomanus and venom of Buthus occitanus by hemagglutination assays.
The goal of this study was found detect activity lectin in venoms of two endemic Colombian species and one no endemic: the rattlesnake Crotalus durissus cumanensis (from Magdalena Medio, Atlantic and Orinoquía region), scorpion Tityus macrochirus (from Cundinamarca region) and the lionfish Pterois volitans (from Atlantic region). For that purpose, representative pool venoms were used.
We used total venom extracts, equilibrated with physiological buffers and enriched with ions (Ca++ and/or Mn++) in some cases. The lectins were purified using affinity chromatography columns which are coupled with carbohydrates such as melibiose, fucose and mannose. Elution from components retained were carried out with different ionic force and/or the carbohydrate specific recognition. A previous step was performed by using ionic exchange in FPLC. Activity fractions were tested by hemagglutination assays over rabbit, horse and human (ABO) erythrocytes showing strong agglutination in a quantitative scale of +4. SDS-PAGE under non-reducing conditions showed bands around 26 kDa related to lectin in vipers, 36 kDa related to the lectin in lionfish venom and the lectin in Tityus macrochirus scorpion venom around 100 kDa.
This is the first report of lectin isolation in Colombian rattlesnake, lionfish and a scorpion venom and reinforces the studies on the protein and peptide composition of animal venoms that, as in the case of lectins, have therapeutic potential as aggregators and platelet antiaggregation therapy, antimicrobials, antifungals, cytotoxic and anti-metastatic, among others. The Protein Research Group (GRIP) of the Universidad Nacional de Colombia continues working on the isolation and characterization of lectins, carrying out studies of primary to tertiary structure in order to study its biological and pharmacological activity.