Isolamento, purificação e caracterização parcial de uma lectina de sementes de Andira surinamensis (BONDT.) Splitz ex Pulle

Abstract

In the plant kingdom, Papilionoideae, a Leguminosae sub-family is without a question the most studied group of lectins as purification and characterization. Despite of that, news lectins with different and interesting properties have been discovered in this group of plants. This work shows purification and partial characterization of a mannose-binding lectin from Andira surinamen.ns seeds (Leguminosae, Papilionoideae, Dalbergieae) it was denominated ASL. Eletrophoretic profile by PAGE-SDS shows different protein bands as in galactose-binding lectin from Vaitarea macrocarpa (VML) seeds and N-acetyl-glucosaminebinding lectin from Lonchocarpus sericeus seeds, both from Dalbergieae tribe. ASL has amino acid composition like VML, rich in Asparagine/Aspartic acid, Alanine, Serine and Threonine. By the way, ASL has a extinction coefficient [Eo gym. %) = 20,04] different from VML [E0 ~m ,a = 5,60], showing that the position of aromatic amino acids (despite of a similar composition in both lectins) must be hardily different between them. N-terminal analysis give two sequences, a major one and a minor one, both with great similarity with VML sequence. Those results, as much those obtained by PAGE-SDS, indicate that ASL, as showed before by VML, has a isolectin mixture with intact and fragmented chains. The presence of lectins with endogenous and actives fragments that arises after pos-traditional modification was found only in lectins from Diocleinae tribe. Most over, ASL as much as VML even belonging to Dalbergeae tribe what is less evoluted and filogeneticly far from Diocleinae, also shows the same pattern. In biological point of view, ASL shows bactericide activity to gram-negative bacteria Xanthomonas axonopodis pv. Passfiorae, a pathogenic bacteria of Passiflora plants (flower-passion).