Nanoscale Mapping of Multiple Lectins on Cell Surfaces by Single‐Molecule Force Spectroscopy

Abstract

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, 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 this study, the spatially resolved localization, identification, and quantification of multiple carbohydrate‐binding sites are directly revealed on the surface of fungal pathogen Aspergillus fumigatus. Nanoscale reconstructed mapping from several recognition maps, corresponding each to a unique specific interaction probed by single‐molecule force spectroscopy, shows the distribution of carbohydrate‐binding sites on the pathogen surface. The identified binding sites are then blocked with the appropriate carbohydrate, attesting the possibility to control lectin‐mediated host–pathogen interactions. Germination markedly affects both the spatial distribution of carbohydrate‐binding sites, mostly expressed at the apex of hyphae, and the identity of the predominant ones, which depend on the location on germ tubes. These insights clearly open exciting avenues in nanomedicine to control host–pathogen interactions with the development of vaccines or inhibitory drugs that preferentially target the identified carbohydrate‐binding sites.

Applications of mannose-binding lectins and mannan glycoconjugates in nanomedicine

“…A wide spectrum of proteins, similar to bacteria, bind high-mannose carbohydrates found on HIV’s envelope protein gp120, offering a novel strategy to regulate HIV infection [ 20 , 21 ]. In-depth knowledge of host–pathogen interaction is essential for production of vaccines or repressive drugs that favourably target the identified lectin receptors [ 22 ].…”

Interactions between infernan and calcium: From the molecular level to the mechanical properties of microgels

“…For this purpose, polysaccharide-Ca 2+ interactions were firstly studied at the molecular level by combining an experimental approach based on atomic force microscopy (AFM) with a theoretical one, exploiting molecular dynamics simulations. AFM constitutes a powerful tool allowing to image biological structures with nanometric resolution, to measure the forces between single molecules with piconewton sensitivity and to probe the mechanical properties (Cuenot, Bouvrée, & Bouchara, 2017;Florin, Moy, & Gaub, 1994;Hinterdorfer & Dufrêne, 2006;Zykwinska et al, 2018). Molecular dynamics simulations allowed to establish the molecular conformations of the polysaccharide chains upon Ca 2+ binding.…”