Bauhinia lectins: Biochemical properties and biotechnological applications

Lectins are proteins of non-immune origin present throughout all kingdoms of life. They are capable of binding to specific carbohydrates reversibly, thus performing several biological roles. Plant lectins are the most studied ones, with hundreds of isolated and characterized hemagglutinins. Most of the known lectins have been isolated from plants belonging to family Leguminosae, which includes genus Bauhinia. This genus comprises over 300 species located in the tropical zones of the planet, where these are utilized in folk medicine because of their numerous medicinal effects, such as anti-inflammatory and antidiabetic actions. Despite being studied for over fifty years, the literature regarding Bauhinia hemagglutinins is scarce, describing just ten proteins isolated from seven different species. Structurally as well as biophysically, there is great similarity among all the known Bauhinia lectins, which may classify them as chemotaxonomic markers; however, the carbohydrate-binding sites and further specificities are unique for each of these proteins. The activities identified for these lectins include growth inhibition in cancer cell lines, cell marking, anti-inflammatory and insecticidal effects, which are just a few among their various other activities of high economic importance. Besides their versatility, four recombinant Bauhinia lectins have already been successfully expressed in heterologous microbial systems, further suggesting that these proteins could serve as promising biotechnological products in future.