Biochemical and structural properties of a lectin purified from seeds of the legume Parkia nitida Miq.

Abstract

As the main carbohydrate-binding proteins, lectins are responsible for several biological functions, although their specific roles are still being unveiled. In the current work, a jacalin-related lectin from the seeds of Parkia nitida (Fabaceae family, Mimosoideae subfamily) was isolated by a combination of saline precipitation, mannose affinity chromatography, and gel filtration chromatography. The lectin, henceforth designated as PNL, demonstrated remarkable similarity to other Parkia lectins at the biochemical and structural levels. Overall, PNL is a stable lectin with a molecular mass of 48,760.3 Da, composed of 451 amino acid residues that fold into 3 side-by-side β-prism domains, each with its own carbohydrate-recognition domain specific to mannosides. Additionally, PNL displays a degree of toxicity against Artemia sp., albeit weaker than similar lectins. In conclusion, a representative of the Mimosoideae subfamily of legumes could be purified and characterized. This represents an advance in the understanding of Mimosoideae lectins, a group of unique proteins that receive significantly less focus in the plant lectin field.