Purificação, cristalização e avaliação da toxicidade da lectina de Luetzelburgia auriculata (Allemão) Ducke

Abstract

Plant lectins are a group of proteins widely distributed in the plant kingdom, characterized by their ability to recognize and bind specifically to carbohydrates, and are associated with various biological activities. Among these proteins, the lectin isolated from the seeds of Luetzelburgia auriculata (Allemão) Ducke (LAA), a species endemic to the Brazilian territory, stands out and has been little explored from a biochemical and toxicological point of view. In this context, the present study aimed to isolate and purify the lectin from L. auriculata seeds, characterize it by polyacrylamide gel electrophoresis, promote its crystallization for structural studies, and evaluate its toxicity through a bioassay with Artemia salina. LAA purification was performed by affinity chromatography in a guar gum matrix, exploiting its specificity for galactosidi carbohydrates, resulting in a protein fraction with a high degree of purity. Electrophoretic characterization revealed the typical pattern of this lectin, with subunits compatible with its previously described homotetrameric organization. Crystallization assays allowed the obtaining of crystals of both native LAA and LAA complexed with lactose, with better morphological regularity observed in the presence of the ligand. Toxicological evaluation indicated no acute lethal toxicity of LAA on A. salina nauplii, even at the highest concentrations tested, although interference was observed in early developmental events, such as cyst hatching. These results contribute to the structural and biological knowledge of LAA and reinforce its potential for future studies, especially in the context of veterinary medicine.