Determinação estrutural de uma lectina pró-inflamatória de sementes de Vaitarea guianensis (Aublet)

Abstract

Widely distributed in nature, lectins comprise a heterogeneous group of proteins of nonimmune origin, having at least one non-catalytic domain capable of selectively recognizing carbohydrates, and interacting reversibly to free sugars or glycans present in glycoproteins or glycolipids, without altering Structures. The most studied lectins are of vegetable origin, mainly of the family Leguminosae. Within this family stand out the tribes Phaseoleae, Vicieae and Dalbergieae belonging to the subfamily Papilionoideae. Among the lectins of the Dalbergieae tribe, we can highlight a lectin with binding affinity to N-acetyl-D-galactosamine / D-galactose extracted from Vatairea guianensis (VGL) seeds that presented vasodilator effect in vitro with mechanism involving nitric oxide. Some lectins from this same tribe are already characterized biochemically, but only the lectins of Pterocarpus angolensis, Centrolobium tomentosum, Platypodium elegans, Arachis hypogaea and Vatairea macrocarpa have their structures. Structural studies of lectins are used as tools to understand how these proteins behave in the various physiological processes. For lectins that do not yet have their crystallographic structures resolved, Bioinformatics is highlighted using methodologies that predict the three-dimensional structure of these proteins in complex with their ligands. Considering that structural studies with these proteins are still few, the present work had the objective to predict the structure, to study the affinity and the interactions of the lectin of Vatairea guianensis seeds in complex with different glycans applying techniques of bioinformatics, like homology modeling and docking Molecular, in addition to investigating its inflammatory effect in vivo. The VGL model was obtained by homology with Vatairea macrocarpa (VML) lectin and demonstrated common characteristics of legume lectins and the analysis of protein-linker interaction revealed favorable interactions with N-acetyl-D-galactosamine, D-galactose and sugars. As well as various biologically relevant N- and O-glycans. The in vivo paw edema test revealed that VGL induces the edematogenic effect involving prostaglandins, interleukins and the lectin carbohydrate recognition domain. Together, these data corroborate with work already reported in which VGL interacts with N-or O-glycans of target molecules, particularly those with galactosides in their structure, contributing to the inflammatory effect of the lectin.