A ‘glyco-fluorine’ code revealing differential recognition by glycan binding partners

Biosensing or diagnostics using glycan sequences as targets is limited by glycan cross-reactivities. As binding sites of different proteins that all recognise a given glycan will not be identical, we introduce application of a library of synthetic analogues of a single glycan ligand as a powerful approach to obtain fingerprint binding profiles. We report the enzymatic synthesis of a 150-member library of fluorinated Lewisx analogues (‘glycofluoroforms’) using naturally occurring enzymes and fluorinated monosaccharide building blocks, and the incorporation of a subset into lipid-linked glycan probes or into glyconanoparticles for probing protein binding both in solid-phase high-throughput glycan microarray screening analyses and in solution-phase nanoparticle-based interaction studies. These fluorinated Lewisx analogues, which NMR studies showed to have very similar 3D structures compared to the nonfluorinated Lewisx, gave variously increased or decreased binding with a set of proteins, the different proteins having different preferences and tolerances for binding.