CAREER: Rare Sugar Activation and Incorporation into Bacterial Glycan Polymers

在化学系生命过程化学（CLP）项目的支持下，来自纽约大学的Tania Lupoli将研究细菌细胞表面特有的糖的合成和识别。几乎所有的细菌都含有从细胞表面延伸出来的由糖组成的聚合物，称为多糖。许多细菌表面多糖含有罕见的糖，这是细菌特有的单糖，在哺乳动物中不存在，包括人类。虽然科学家们认识到稀有糖对于介导细菌与其环境之间的相互作用很重要，但对于稀有含糖聚合物如何组装以及它们如何在感染期间在宿主中存活，人们仍然不完全了解。提出的实验旨在开发化学方法来研究识别稀有糖的酶，目的是提供化学工具来分析细菌与环境的相互作用。这项工作将使研究生获得合成化学、生物化学和微生物学方面的训练。该项目还将纳入传染病、细菌生存和抗生素设计的教育推广计划，以激励未来的科学家。该研究项目旨在开发核苷酸稀有糖的途径，并定量表征它们与组装细菌表面多糖的糖基转移酶的相互作用。罕见的细菌糖在6-脱氧糖中有过多的表现，6-脱氧糖缺乏己糖环C6上的典型羟基，通常是L-而不是d -异构体。该提案旨在开发试剂，以破译将具有罕见立体化学的糖（缺乏6-羟基）安装到细菌细胞表面的分子后果，重点是革兰氏阴性细菌。将开发具有活性的稀有糖底物的合成和化学酶途径。稀有糖基转移酶的机制和催化位点将通过详细的动力学和诱变研究来确定。这项工作有望帮助建立目前尚未表征的细菌糖基转移酶识别6-脱氧糖的分子规则。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemistry of Life Processes (CLP) program in the Division of Chemistry, Tania Lupoli from New York University will investigate the synthesis and recognition of sugars unique to bacterial cell surfaces. Almost all bacteria contain polymers composed of sugars, called polysaccharides, that extend from their cell surfaces. Many bacterial surface polysaccharides contain rare sugars, which are bacteria-specific monosaccharides that are absent in mammals, including humans. While scientists recognize that rare sugars are important for mediating interactions between bacteria and their environments, there is still incomplete understanding of how rare sugar-containing polymers are assembled and how these enable survival in hosts during infection. The proposed experiments aim to develop chemical approaches to study enzymes that recognize rare sugars, with the goal of providing chemical tools to analyze bacterial interactions with their environments. This work will enable graduate students to obtain training in synthetic chemistry, biochemistry and microbiology. This project will also be integrated into educational outreach programs on infectious disease, bacterial survival and antibiotic design to inspire future scientists.This research project seeks to develop routes to nucleotide rare sugars, and to quantitatively characterize their interactions with glycosyltransferase enzymes that assemble bacterial surface polysaccharides. Rare bacterial sugars are over-represented in 6-deoxysugars, which lack the canonical hydroxyl group found on C6 of the hexose ring, and are typically L- as opposed to D-isomers. This proposal seeks to develop reagents to decipher the molecular consequences of installing sugars with uncommon stereochemistry that lack a 6-hydroxyl group into the cell surface of bacteria, with a focus on Gram-negative bacteria. Robust synthetic and chemoenzymatic routes to activated rare sugar substrates will be developed. The mechanism and catalytic sites of rare sugar-utilizing glycosyltransferases will be determined using detailed kinetic and mutagenesis studies. This work is expected to help establish molecular rules for recognition of 6-deoxysugars by bacterial glycosyltransferases that are currently uncharacterized.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.