Caracterização bioquímica e estrutural de uma lectina da alga marinha vermelha Osmundaria obtusiloba (C. Agardh) R.E. Norris, 1991

Abstract

Advances in biotechnology are bringing new horizons to the contemporary world, given its concern with the improvement, creation and management of new products, such as in biomedicine. In this context, red seaweeds presents as organisms rich in compounds with promising biotechnological potential, including lectins. Lectins constitute a group of proteins or glycoproteins of non-immune origin which bind specifically and reversibly to carbohydrates, and have different biological activities. The studies are expanded due to their potential in the field of health and their wide distribution in organisms. These biological activities are related to protein-carbohydrate interactions of these molecules, therefore, structural studies are important to elucidate the function and indicate the applicability of lectins. The present work aimed the purification and biochemical and structural characterization of a lectin from the red seaweed Osmundaria obtusiloba. OOL (Osmundaria obtusiloba lectin) was purified by combination of saline precipitation, ion exchange and affinity chromatography. The isolated lectin showed on SDS-PAGE a single band with an apparent molecular mass of 15 kDa in the absence of 2-mercaptoethanol, and under reducing conditions it presented a molecular mass of approximately 20,2 kDa. By gel filtration chromatography, its native mass was estimated in 45 kDa and in ESI-MS (Electrospray Ionization - Mass Spectrometry) its molecular mass was 18.474 ±2 Da. OOL was able to agglutinate native rabbit erythrocytes. The hemagglutinating activity of the lectin was inhibited by yeast mannan, porcine thyroglobulin, asialofetuin, human transferrin and present stability at neutral pH. The partial primary structure of OOL was determined by sequencing the peptides by (MS/MS) from tryptic digestion.