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

Carbohydrate-protein interactions trigger a wide range of biological signaling pathways, the mainstays of physiological and pathological processes. However, there are an incredible number of carbohydrate-binding proteins (CBPs) that remain to be identified and characterized. This study reports for the first time the covalent labeling of CBPs by triazinyl glycosides, a new and promising class of affinity-based glycoprobes. Mono- and bis-clickable triazinyl glycosides were efficiently synthesized from unprotected oligosaccharides (chitinpentaose and 2'-fucosyl-lactose) in a single step. These molecules allow the specific covalent labeling of chitin-oligosaccharide-binding proteins (wheat germ agglutinin WGA and Bc ChiA1 D202A, an inactivated chitinase) and fucosyl-binding lectin (UEA-I), respectively.

Efficient Conjugation of Oligosaccharides to Polymer Particles through Furan/Maleimide Diels-Alder Reaction: Application to the Capture of Carbohydrate-Binding Proteins.

Glycan-protein interactions play a crucial role in physiological and pathological events. Hence, improving the isolation of carbohydrate-binding proteins (i.e., lectins and anti-glycan antibodies) from complex media might not only lead to a better understanding of their function, but also provide solutions for public health issues, such as water contamination or the need for universal blood plasma. Here we report a rapid and efficient method for producing carbohydrate-based affinity adsorbents combining enzymatic synthesis and metal-free click chemistry. Both simple and complex glycans (maltose, blood group antigens A, B, and H) were readily modified by the addition of a furyl group at the reducing end without the need for protecting groups and were then efficiently conjugated to maleimide-activated Sepharose particles through Diels-Alder cycloaddition. These neoglycoconjugates showed high efficiency for the purification of lectins (concanavalin A and Ulex europaeus agglutinin), as well as for the capture of anti-A and anti-B blood group antibodies, opening new prospects for glycoproteomics and for the development of universal blood plasma.

Redox tunable delivery systems: sweet block copolymer micelles via thiol-(bromo)maleimide conjugation.

Oligosaccharide-based block copolymers (OBCPs) are synthesized by thiol click conjugation using reducing-end thiol-containing xyloglucooligosaccharides and maleimide- or bromomaleimide-terminated polycaprolactone. The self-assembled OBCPs in aqueous solution lead to redox-sensitive micelles with different responsiveness. This distinguishing feature allows us to control the release of entrapped hydrophobic Nile red by mixing both OBCPs.