Meshing Synthesis and Biosynthesis for KDO: A Key Plant and Bacterial Sugar

KDO（2-酮-3-脱氧-d -甘露-辛糖酸）是一种不寻常的8碳酸性糖，对许多影响植物和动物的致病菌的生长至关重要。例如，在革兰氏阴性菌（如布鲁氏菌）中，KDO是脂质基脂多糖的关键部分，这种细菌会导致人类和生物的严重感染。在植物和绿藻中也发现了KDO，尽管其在这些生物中的生物学作用尚不清楚。这种糖的高成本加上化学合成的挑战，限制了KDO合成化学的基础科学研究，它的生物学作用，以及基于抑制KDO通路的抗生素的开发。该项目旨在1)优化工程努力，从细菌来源获得克量的KDO； 2)研究将KDO与其他结构连接起来的化学方法；3)探索在自动化溶液相低聚糖合成平台中使用KDO构建块的协议，将这种糖纳入更大的生物活性结构。4)测试KDO与一系列被称为凝集素的植物碳水化合物结合蛋白的结合，以发现这种病原体相关糖的潜在结合伙伴。更广泛的影响：这个跨学科项目将扩大代表性不足群体的参与，包括来自代表性不足群体的学生作为拟议研究和教育活动的参与者；通过将研究生和本科生作为参与者并鼓励他们参加国内和国际科学会议，促进发现和理解，同时促进教学、培训和学习；并开发第一个基于发酵的生产工艺和一种不寻常的糖的新化学反应，这种糖对植物和动物的细菌感染性至关重要，以帮助解开感染过程并最终抑制这些感染。

KDO (2-keto-3-deoxy-D-manno-octulosonic acid) is an unusual 8-carbon acidic sugar that is essential for the growth of many pathogenic bacteria affecting plants and animals. For example, in Gram-negative bacteria such as Brucella, which causes severe infections in humans and lifestock KDO is a crucial part of the Lipid A-based lipopolysaccharides. KDO has also been discovered in plants and green algae, although its biological roles in these organisms are still unclear. The high cost of this sugar coupled with the challenge of making it by chemical synthesis has limited basic scientific studies of the synthetic chemistry of KDO, its biological roles, and the development of antibiotics based on inhibiting KDO-based pathways. This project aims to 1) optimize engineering efforts to obtain KDO in gram quantities from a bacterial source, 2) investigate chemical methods to link KDO to other structures, 3) explore protocols to use KDO building blocks in an automated solution-phase oligosaccharide synthesis platform to incorporate this sugar into larger bioactive structures, and 4) test the binding of KDO to a range of plant carbohydrate-binding proteins called lectins to discover potential binding partners of this pathogen-associated sugar. Broader Impact: This interdisciplinary project will broaden the participation of underrepresented groups by inclusion of students from underrepresented groups as participants in the proposed research and education activities; advance discovery and understanding while promoting teaching, training, and learning by inclusion of graduate and undergraduate students as participants and the encouragement of their participation at national and international scientific meetings; and develop the first fermentation-based production processes and new chemistry of an unusual sugar key to bacterial infectiousness of plants and animals to help unravel the infection processes and ultimately inhibit these infections.