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: 10459500
• 负责人: Tania Lupoli
• 金额: $ 34.25万
• 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/10459500
• 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.

项目摘要/摘要 我们的星球上居住着数以万亿计的细菌，它们生活在人类体内和外部。“皮肤”，或 细菌的表面被称为细胞膜，它的功能是将我们与细菌隔开。虽然有些细菌 虽然是共生菌，但病原菌感染仍然是世界范围内死亡的主要原因。而革兰氏阴性 细菌含有一层保护性的外膜，在大多数革兰氏阳性菌中没有，几乎所有的细菌都含有 由从细胞表面延伸出来的独特图案的多聚糖组成的聚合物。细菌表面糖 聚合物，或胞外多糖，充当分子条形码，区分不同菌株的细菌 一个单一的物种。许多细菌胞外多糖含有稀有糖，这种单糖是 在包括人类在内的其他生物中不存在。虽然胞外多糖是宿主感染所必需的，但我们 仍然缺乏对罕见的含糖多聚糖聚合物是如何组装、识别和使 在宿主体内生存。 我的实验室致力于制造化学和生化工具来研究细菌蛋白质和多糖 能够在不同环境中生存的途径。我们主要关注的领域是：(1)发展小型企业 细菌伴侣功能的分子调节；(2)操纵细胞表面糖模式以选择性地 给细菌贴上标签并禁用。这项建议侧重于后一项计划，在该计划中，我们确定了稀有糖类 革兰氏阴性细胞表面聚合物所特有的亚基，称为O-抗原，代表关键表位 调节与宿主的相互作用和对抗生素的敏感性。在未来五年，我们将解决 以下问题：(1)我们能否改进化学酶途径以获得稀有糖前体底物？(2)如何 糖基转移酶识别稀有的糖底物来构建O-抗原吗？(3)O-抗原 通过蛋白质-蛋白质相互作用调节的糖基转移酶？(4)什么是宿主蛋白质结构基序 参与细菌稀有糖的识别？(5)我们能否识别与细菌有关的新宿主蛋白？ 认同感？为了回答这些问题，我们将使用多学科方法，包括 有机化学、化学生物学、生物化学、微生物学和测序分析。这项工作将 极大地扩展了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。 与公共健康的相关性：除了提供对细菌因素产生的基本见解之外 这些对感染很重要，这项提案的结果将为禁用难治性疾病的新策略提供信息 主要宿主-病原体相互作用和生物分子干扰所致的革兰氏阴性感染 用于新诊断的识别细菌低聚糖结构的试剂。