A microbial glycan production platform for glycoscience research

聚糖存在于几乎所有的生命形式中，包括植物、动物和微生物。它们表现出显著的结构多样性和复杂性，使它们能够参与各种关键的生理和病理生理过程，包括细胞信号传导、生长、发育、感染、转移、防御或免疫、营养和疾病。聚糖的重要性还体现在它们的开发导致了几种高价值生物制品的发展，包括治疗剂、疫苗、药物输送系统、诊断和其他基于聚糖的商业产品，如胶凝剂、增稠剂、动物饲料和生物燃料，这些产品极大地提高了人类、植物健康和生物经济。然而，由于多糖结构的复杂性，对多糖代谢和功能的了解有限，以及方法和工具的可用性，多糖的研究受到了很大的阻碍。值得注意的是，化学上定义的聚糖亚结构或低聚糖（CDGOs）、糖缀合物和高通量技术来推进聚糖研究的途径非常有限。这极大地限制了我们开发聚糖全部潜力的能力。最近，我们开发了一种高度可扩展的遗传和生化方法，使用工程化的人类肠道细菌从一些自然界最复杂的聚糖中产生和纯化多种cdgo。这些分别包括动物和植物来源的聚糖硫酸软骨素和果胶鼠李糖半乳糖醛酸- ii。我们将这种方法成功地应用于这些来自进化遥远来源的聚糖，这表明这种方法可能适用于广泛的其他聚糖，包括微生物聚糖，并且可能代表一种可行的替代化学和化学酶合成聚糖的方法，这些方法对于高度复杂的聚糖来说是非常繁琐和昂贵的。本项目旨在通过研究可从已证实的聚糖中生成的CDGO的范围，并测试其对新聚糖的适用性，进一步探索这种方法。生成的cdgo也将被用于揭示复杂的聚糖结构、功能和代谢，例如，通过开发高通量糖阵列来探测与人类和植物健康和疾病相关的碳水化合物活性酶和凝集素。候选人将学习细菌基因工程技术，原核和真核基因克隆和表达，酶学，聚糖分析技术（如质谱，核磁共振）和结构生物学。

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.