Structural studies of a vasorelaxant lectin from Dioclea reflexa Hook seeds: Crystal structure, molecular docking and dynamics

- We present the primary and three-dimensional structure of Dioclea reflexa Hook seed lectin (DrfL).
- We evaluated the vasorelaxant effect of DrfL in rat aortic rings.
- Molecular docking and dynamics analysis of DrfL structure was performed.
- Carbohydrate-recognition domain volume analysis by molecular dynamics simulations was evaluated.

The three-dimensional structure of Dioclea reflexa seed lectin (DrfL) was studied in detail by a combination of X-ray crystallography, molecular docking and molecular dynamics. DrfL was purified by affinity chromatography using Sephadex G-50 matrix. Its primary structure was obtained by mass spectrometry, and crystals belonging to orthorhombic space group P212121 were grown by the vapor diffusion method at 293 K. The crystal structure was solved at 1.765 Å and was very similar to that of other lectins from the same subtribe. The structure presented Rfactor and Rfree of 21.69% and 24.89%, respectively, with no residues in nonallowed regions of Ramachandran plot. Similar to other Diocleinae lectins, DrfL was capable of relaxing aortic rings via NO induction, with CRD participation, albeit with low intensity (32%). In silico analysis results demonstrated that DrfL could strongly interact with complex N-glycans, components of blood vessel glycoconjugates. Despite the high similarity among Diocleinae lectins, it was also reported that each lectin has unique CRD properties that influence carbohydrate binding, resulting in different biological effects presented by these molecules.