RESUMO
Lectins are proteins that have as one of their main characteristics recognizing and reversibly binding to carbohydrates. In this work, it was possible to purify and characterize a lectin from Parkia panurensis (Leguminosae family; Mimosoideae subfamily) seeds by a combination of the techniques: protein precipitation, along with affinity and then ion exchange chromatography using the Sepharose-mannose and diethylaminoethyl matrices, respectively. The pure lectin, called PpaL, has affinity by D-mannose, D-glucose and derivatives. PpaL was stable over a wide range of temperature and pH, and it showed an SDS-PAGE profile of only one protein band with apparent mass of 45 kDa, subsequently confirmed by mass spectrometry, and presented a molecular mass of 50,566 ± 1 Da. PAGE analysis and molecular exclusion chromatography demonstrated that PpaL is presented as a dimer in solution. Partial sequencing of the primary structure resulted in a total of 334 amino acid residues with approximately 97% similarity to Parkia biglobosa and Parkia platycephala seed lectins. PpaL was shown to be toxic against Artemia nauplii and had an LC50 of 20 µg/mL. The effects of biological activities presented by these proteins make them important biotechnological tools, demonstrating the importance of bioprospection of new lectins.
