NANOSCALE MAPPING OF MULTIPLE LECTIN SITES ON CELL SURFACES DETECTED BY CARBOHYDRATE-FUNCTIONALIZED AFM TIPS

摘要

Molecular recognition events driven by protein-carbohydrate interactions play fundamental roles in various physiological and pathological processes in living organisms, including cohesion inside tissues, innate immune response, cancer cell metastasis and infections. Unlike widely investigated carbohydrates, a detailed knowledge of both the spatial organization of specific lectins and their identification on cell surfaces remains an essential prerequisite for the understanding of pathogen adhesion to host tissues and subsequent infection prevention. In the present work, we report an elegant and selective means to reveal the localization with nanometre scale resolution of multiple carbohydrate-binding sites and their identification directly on the surface of fungal pathogen Aspergillus fumigatus [1]. Indeed, single-molecule force spectroscopy experiments were conducted with different carbohydrate-functionalized atomic force microscopy (AFM) tips to perform several nanoscale recognition maps, corresponding each to a unique specific receptor-ligand interaction. These recognition maps were then superimposed to build a spatial mapping of lectin site distribution on the pathogen surface. The nanoscale reconstructed mapping reveals a high coverage ratio of various carbohydrate-binding sites, allowing them to be spatially localized, identified and quantified [1]. In a subsequent step, the identified binding sites were blocked with the appropriate carbohydrate, attesting the possibility to control lectin-mediated host-pathogen interactions.