Self assembly of Human Galectin 1 via dual supramolecular interactions and its inhibition of T cell agglutination and apoptosis

Recently, we proposed a new strategy to construct artificial plant protein assemblies, which were induced by adding a small molecule, based on dual supramolecular interactions. In this paper, we further explored this method by employing Human Galectin 1 Gal 1 as a building block to form self assembled microribbons. Two non covalent interactions, including lactose lectin binding and dimerization of Rhodamine B RhB , induced by the small molecule ligand addition, were involved in the crosslinking of the animal protein, resulting in the formation of assemblies. By using transmission electron microscopy TEM , cryo electron microscopy cryo EM , and three dimensional 3D tomographic analysis, we arrived at a possible mechanistic model for the microribbon formation. Furthermore, the morphology of protein assemblies could be fine tuned by varying the incubation time, the protein ligand ratio, and the chemical structures of ligands. Interestingly, the formation of protein microribbons successfully inhibited Gal 1 induced T cell agglutination and apoptosis. This is because the multivalent and dynamic interactions in protein assemblies compete with the binding between Gal 1 and the glycans on cell surfaces, which suppresses the function of Gal 1 in promotion of tumor progression and metastasis