A microbial glycan production platform for glycoscience research

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Glycans are present in almost all life forms including plants, animals and microorganisms. They exhibit remarkable structural diversity and complexity, enabling them to participate in a variety of critical physiological and pathophysiological processes including cell signalling, growth, development, infection, metastasis, defence or immunity, nutrition and disease. The importance of glycans is also exemplified by the fact that their exploitation has led to the development of several high value biologicals including therapeutics, vaccines, drug delivery systems, diagnostics and other glycan-based commercial products such as gelling agents, thickening agents, animal feeds and biofuels which have greatly enhanced human, plant health and the bioeconomy. Glycan research is however, greatly hampered by the structural complexity of glycans, limited knowledge of glycan metabolism and function and availability of methods and enabling tools. Notably, there is very limited access to chemically defined glycan substructures or oligosaccharides (CDGOs), glycoconjugates and high throughput technologies to advance glycan studies. These significantly limit our ability to exploit the full potential of glycans. Recently we developed a highly scalable genetic and biochemical approach using engineered human gut bacteria to produce and purify a diverse range of CDGOs from some of nature's most complex glycans. These include the animal and plant-derived glycans chondroitin sulphate and pectin rhamnogalacturonan-II respectively. Our success in applying this approach to these glycans from evolutionary distant sources suggests that this approach is likely to be applicable to a vast range of other glycans including microbial glycans and could represent a viable alternative to chemical and chemo-enzymatic glycan synthesis approaches which can be very tedious and costly for highly complex glycans. This project aims to further explore this approach by investigating the range of CDGO's that can be generated from proven glycans and testing its applicability to new glycans. CDGOs generated will also exploited to shed new light into complex glycan structure, function and metabolism e.g., through the development of high-throughput glycoarrays to probe carbohydrate-active enzymes and lectins relevant in human and plant health and disease. The candidate will learn techniques in bacterial genetic engineering, prokaryotic and eukaryotic gene cloning and expression, enzymology, glycan analytical techniques (e.g., mass spectrometry, nuclear magnetic resonance) and structural biology.