Caracterização estrutural e biológica de uma lectina de sementes de centrolobium tomentosum guill. ex benth

Abstract

A glycosylated lectin (CTL) with specificity for mannose and glucose has been detected and purified from seeds of Centrolobium tomentosum, a legume plant from the Dalbergieae tribe. CTL was isolated by mannose-Sepharose affinity chromatography. The primary structure was determined by tandem mass spectrometry and consists of 245 amino acids and one N-glycosylation site, possessing high similarity with the lectin Platypodium elegans (PELa) and Pterocarpus angolensis (PAL) derived from the same tribe. Two crystal structures of CTL, with monoclinic and tetragonal forms, both complexed with methyl dimanosídeo has been solved at 2.25 and 1.9 Å, respectively, with high similarity. The lectin adopts a typical canonical dimeric organization of legume lectins. The carbohydrate recognition domain (CRD), metal binding site, and glycosylation site have been characterized and the structural basis for interaction with carbohydrate been elucidated. CTL showed acute inflammatory effect in a paw edema model. The protein structure was subjected to ligand screening (dimannosides and trimannoside) by molecular docking, revealing a higher affinity for trimannosides and their interactions were compared with similar lectins, which have the same binding specificity. This is the first report of a crystal structure of a native mannose lectin / specific glucose Dalbergieae tribe with pro-inflammatory activity