Chemoenzymatic preparation ofprobes for in vitro and cellular elucidation of complex bacterial polysaccharides

Bacteria play a major role in our health and wellbeing. The microbe-host interaction is often mediated by sugar polymers at the cell surface. An incredibly diverse amount of glycan variation exists throughout these structures, which makes identification of surface components difficult. The composition of the surface is unique to bacteria and acts as molecular fingerprint which can distinguish even subspecies apart. Better methods to decipher what those glycan identities are or how to reproduce them may help develop future advancements towards exploiting them as therapeutic targets. The major challenge addressed herein is to simplify the tools used to track the formation of these natural materials. To do this, we expand on the chemoenzymatic preparation of a tagged lipid substrate central to early stages of biosynthesis for many surface polysaccharides. Further, we identify conditions in which these unnatural substrates can be used in vitro. Lastly, we develop methodologies to detect BP and polysaccharide intermediates in live cells. These tools have facilitated robust detection and reconstruction of glycan assembly building blocks. This research may lay the ground work for future applications technologies towards novel therapeutics, such as glycoconjugates vaccines.