MIRA: Probing Glycan Polymer Patterns on Bacterial Cell Surfaces

MIRA：探测细菌细胞表面的聚糖聚合物模式

• 批准号: 10275911
• 负责人: Tania Lupoli
• 金额: $ 34.28万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10275911
• 关键词: Address; Antibiotics; Area; Bacteria; Bacterial Polysaccharides; Bacterial Proteins; Bar Codes; Biochemistry; Biology; Cause of Death; Cell surface; Chemicals; Development; Environment; Epitopes; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Human; Infection; Label; Laboratories; Mediating; Membrane; Microbiology; Molecular; Molecular Chaperones; Monosaccharides; O Antigens; Oligosaccharides; Organic Chemistry; Organism; Outcome; Pathway interactions; Pattern; Planets; Polymers; Polysaccharides; Predisposition; Production; Proteins; Public Health; Reagent; Route; Skin; Structure; Surface; Work; base; biochemical tools; cell envelope; glycosyltransferase; improved; insight; interdisciplinary approach; molecular recognition; novel diagnostics; novel strategies; pathogen; pathogenic bacteria; programs; protein protein interaction; small molecule; sugar; symbiont

Project Summary/Abstract Our planet is inhabited by trillions of bacteria that live inside and outside of humans. The “skin”, or surface, of bacteria is called the cell envelope, and functions to separate us from them. Although some bacteria are symbionts, infection by pathogenic bacteria is still a major cause of death worldwide. While Gram-negative bacteria contain a protective outer membrane layer absent in most Gram-positives, almost all bacteria contain polymers composed of unique patterns of glycans that extend from the cell surface. Bacterial surface sugar polymers, or exo-polysaccharides, act as molecular barcodes that distinguish different strains of bacteria within a single species. Many bacterial exo-polysaccharides contain rare sugars, which are monosaccharides that are absent in other organisms, including humans. While exo-polysaccharides are necessary for host infection, we still lack an understanding of how rare sugar-containing glycan polymers are assembled, recognized, and enable survival in the host. My laboratory seeks to generate chemical and biochemical tools to study bacterial protein and glycan pathways that enable survival in different environments. Our main areas of focus are: (1) development of small molecule regulators of bacterial chaperone function; (2) manipulation of cell surface sugar patterns to selectively label and disable bacteria. This proposal focuses on the latter program, in which we identify rare saccharide subunits that are unique to Gram-negative cell surface polymers called O-antigens, and represent key epitopes that mediate interactions with hosts and susceptibility to antibiotics. Over the next five years, we will address the following questions: (1) Can we improve chemoenzymatic routes to rare sugar precursor substrates? (2) How do glycosyltransferases recognize rare sugar substrates to build O-antigens? (3) Are O-antigen glycosyltransferases regulated via protein-protein interactions? (4) What host protein structural motifs are involved in bacterial rare sugar recognition? (5) Can we identify new host proteins involved in bacterial recognition? To answer these questions, we will use a multidisciplinary approach, involving a combination of organic chemistry, chemical biology, biochemistry, microbiology and sequencing-based analyses. This work will significantly expand our understanding of cellular mechanisms underlying bacterial polysaccharide synthesis, and will teach us how humans recognize foreign sugars. Relevance to public health: In addition to providing fundamental insight into the production of bacterial factors that are important for infection, the results of this proposal will inform novel strategies to disable hard-to-treat Gram-negative infections by interference of essential host-pathogen interactions, as well as biomolecular reagents to recognize bacterial oligosaccharide structures for new diagnostics.

项目概要/摘要 我们的星球上栖息着数万亿个细菌，它们生活在人类的体内和体外。 细菌的表面称为细胞膜，其功能是将我们与细菌分开。 虽然革兰氏阴性菌是共生体，但致病菌感染仍然是全球死亡的主要原因。 细菌含有大多数革兰氏阳性菌所没有的保护性外膜层，几乎所有细菌都含有 由从细菌表面糖延伸的独特模式的聚糖组成的聚合物。 聚合物或外多糖充当分子条形码，区分体内不同的细菌菌株 许多细菌外多糖含有稀有糖，它们是单糖。 虽然外多糖对于宿主感染是必需的，但在其他生物体中不存在，包括人类。 仍然缺乏对罕见的含糖聚糖聚合物如何组装、识别和启用的了解 在宿主体内生存。 我的实验室致力于开发化学和生化工具来研究细菌蛋白质和聚糖 我们的主要关注领域是：（1）小型化的发展。 (2) 操纵细胞表面糖模式以选择性地 该提案重点关注后一个计划，其中我们识别了稀有糖。 革兰氏阴性细胞表面聚合物（称为 O 抗原）特有的亚基，代表关键表位 介导与宿主的相互作用和对抗生素的敏感性在接下来的五年中，我们将解决这个问题。 以下问题：（1）我们能否改进稀有糖前体底物的化学酶途径？（2）如何改进？ 糖基转移酶是否识别稀有糖底物来构建 O 抗原？ (3) 是 O 抗原吗？ (4) 糖基转移酶通过蛋白质-蛋白质相互作用进行调节？ 参与细菌稀有糖识别？（5）我们能否鉴定出参与细菌的新宿主蛋白？ 为了回答这些问题，我们将采用多学科的方法，涉及多种学科的结合。 这项工作将涉及有机化学、化学生物学、生物化学、微生物学和基于测序的分析。 显着扩展我们对细菌多糖合成的细胞机制的理解， 并将教我们人类如何识别外来糖。 与公共卫生的相关性：除了提供对细菌因子产生的基本了解之外 对于感染很重要，该提案的结果将为消除难以治疗的新策略提供信息 通过干扰重要的宿主-病原体相互作用以及生物分子而引起的革兰氏阴性菌感染 识别细菌寡糖结构以进行新诊断的试剂。