Gold nanoparticle-based multivalent carbohydrate probes: selective photoaffinity labeling of carbohydrate-binding proteins

Multivalent carbohydrate photoaffinity probes were developed based on gold nanoparticles (AuNPs) to provide a streamlined approach toward identification of carbohydrate-binding proteins. By using AuNPs as scaffolds, a carbohydrate ligand and a photoreactive group could be readily assembled on a probe in a modular fashion, which greatly accelerated the process of optimizing the probe design. The novel AuNP-based probes serve dual functions by facilitating photoaffinity labeling and by directly enriching the crosslinked proteins by centrifugation. We demonstrated that their ability to enhance the affinity and to stringently remove nonspecific proteins allowed selective photoaffinity labeling and isolation of a low affinity carbohydrate-binding protein in cell lysate.