Purificação e caracterização bioquímica de uma lectina extraída do fluido celomático do ouriço-do-mar, Echinometra lucunter, exposto a indução bacteriana

Abstract

The Echinodermata Phylum comprises a group of marine animals with about 7,000 species. The name "echinodermata" (L.echinatus, prickly, + Gr. Derma, skin + ata, characterized by) derives from the presence of external spines or protuberances. They are marine animals, but with some estuarine representatives, are important components of the coastal bento. The main representatives of the phylum are starfish, ofiurus, sea urchins, sea cucumbers, sea biscuits and sea lilies. In recent years, a significant number of lectins present in marine invertebrates have been isolated, and studies suggest that they represent an important component in the defense of these organisms, being part of the innate immune system of the animals. Lectins are proteins capable of reversibly binding to specific carbohydrates without modifying their structure. In marine invertebrates, lectins may play an immunological defense role; however, these proteins may participate in several other biological processes in different organisms. The present work aimed to purify and characterize biochemically a lectin extracted from the coelomic fluid of the sea urchin, Echinometra lucunter, exposed to bacterial induction. ELA (Echinometra lucunter agglutinin) was isolated by combination of hydrophobic interaction and size exclusion chromatography. The novel lectin has a native molecular mass of approximately 145 kDa, on SDS PAGE, ELA showed a band of approximately 45 kDa in the presence and absence of 2-mercaptoethanol. Its activity was stable at neutral-alkaline pH and with optimum temperature at 50 ° C, it was also shown to be dependent on divalent ions. ELA had its activity inhibited by mucin glycoproteins type II and III of porcine stomach.