Photoaffinity Probes for Identification of Carbohydrate‐Binding Proteins

Abstract

Carbohydrate‐protein interactions mediate cellular signals, which are crucial in a diverse array of biological and pathological processes. Despite their importance, many carbohydrate‐protein interactions remain unknown due to inherent difficulties in studying them. With the aim to provide the first step in elucidating the biological roles of carbohydrates, photoaffinity labeling has been used as a promising chemical strategy for the detection and identification of carbohydrate‐binding proteins in their native environment. Recent efforts in the design of carbohydrate‐based photoaffinity probes include the use of selective photoreactive groups, development of biotinylated photoreactive groups and linkers, multivalent carbohydrate ligands, affinity‐based protein profiling probes, and photoreactive monosaccharide precursors for metabolic glycan labeling. These methods offer new tools to address challenges associated in capturing the often elusive carbohydrate‐protein interactions.

Current advances of carbene-mediated photoaffinity labeling in medicinal chemistry

“…Carbohydrates constitute integral components of the cell machinery in the forms of polysaccharides, proteoglycans, glycoproteins, glycolipids, and glycosylated secondary metabolites and play crucial roles in a wide range of biological and pathological processes. 116 However, there are still many carbohydrate–protein interactions that remain unknown owing to transient and low-affinity interactions. 117 The use of carbene-mediated photocrosslinking of sugars represents a powerful strategy for investigating carbohydrate–protein interactions in their native context.…”

Target Protein Identification on Photocatalyst‐Functionalized Magnetic Affinity Beads

“…Labeled proteins of interest can be detected by fluorescence or chemical luminescence, or purified by avidin chromatography, and identified by mass spectrometric analysis. However, detection and identification of proteins of interest is often difficult because of the low efficiency of covalent bond formation with photoaffinity probes (<10%; Hashimoto & Hatanaka, 2008;Sakurai, 2015).…”

Unprecedented Affinity Labeling of Carbohydrate-Binding Proteins with s-Triazinyl Glycosides

“…The structure of these probes must be close to that of the original ligand, but should also allow the introduction by bio-orthogonal reactions of chemical reporters, such as a fluorescent group or an isotope, and of an affinity tag for purification. To date, most glycoprobes reported in the literature are photoactivatable cross-linking compounds derived from mono- and disaccharides. , The synthesis of oligosaccharide probes is much less well studied. Among the few examples, gangliosides and Lewis X saccharidic portions have been successfully functionalized with AffiLight CHO, an aminoxy-biotinyl-phenyldiazirine reagent, but to the best of our knowledge, no biological study with these molecules has been reported to date.…”