Biochemical Investigations of Sugar-Modifying Enzymes

糖修饰酶的生化研究

• 批准号: 10548737
• 负责人: Hazel M. Holden
• 金额: $ 38.88万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10548737
• 关键词: Acids; Acinetobacter baumannii; Anabolism; Antibiotics; Award; Bacteria; Bacteriophages; Biochemical; Campylobacter jejuni; Carbohydrates; Carbon; Categories; Cell surface; Complex; Data; Development; Drug Design; Enzymes; Glycoconjugates; Goals; Gram-Negative Bacteria; Immune response; Immune system; Invaded; Investigation; Kinetics; Knowledge; Link; Lipid A; Lipopolysaccharides; Membrane; Modification; Molecular; Molecular Weight; Monosaccharides; O Antigens; Oligosaccharides; Organism; Pathogenicity; Physiological; Play; Polysaccharides; Production; Research; Resistance; Role; Serum; Site-Directed Mutagenesis; Structure; Surface; Techniques; Variant; Virulence; World Health Organization; X-Ray Crystallography; antimicrobial drug; enzyme activity; macromolecule; phosphoramidate; sugar

PROJECT SUMMARY/ABSTRACT Bacteria produce an astonishingly diverse array of carbohydrate-based macromolecules that serve important physiological roles. The lipopolysaccharide or LPS, for example, is a complex glycoconjugate attached to the outer membranes of Gram-negative bacteria. Conceptually, the LPS can be thought of in terms of three regions: the lipid A component, the core oligosaccharide, and the O-antigen. It is the O-antigen that displays the most variation from species to species and that, in addition to the lipid A moiety, plays a role in virulence. Likewise, the capsular polysaccharides, which surround both pathogenic Gram-positive and Gram- negative bacteria, serve as the first lines of defense against the host immune system. These high molecular weight polysaccharides function by camouflaging cell surface components that would normally elicit the immune response. Often the sugars in the capsular polysaccharides are modified by the attachment of a variety of moieties including an O-methyl phosphoramidate group, which has been shown to be involved in host invasion and bacteriophage recognition. In addition, some capsular polysaccharides contain nonulosonic acids, nine-carbon based monosaccharides that have been implicated in virulence. The intellectual goals of this MIRA award are threefold: (1) to expand upon our current knowledge of the structures and activities of the enzymes involved in the biosynthesis of O-antigen sugars, (2) to provide a molecular framework for understanding the biosynthesis of the O-methyl phosphoramidate group in Campylobacter jejuni, and (3) to explore the structures and functions of the enzymes involved in the biosyntheses of nonulosonic acids from Acinetobacter baumannii, an organism that has been placed into the “Critical” category by the World Health Organization for the development of new antibiotics. Techniques to be utilized include X-ray crystallography, site-directed mutagenesis, and kinetic analyses. Importantly, preliminary data for many of the proposed investigations are already available. Our studies have and will continue to inform research into bacterial pathogenicity. Given that the LPS and capsular polysaccharides play critical roles in bacterial virulence, the enzymes to be investigated may ultimately serve as targets for antimicrobial drug design.

项目概要/摘要 细菌产生令人惊讶的多样化的基于碳水化合物的大分子，这些大分子可用于 例如，脂多糖或 LPS 是一种复杂的糖复合物。 从概念上讲，LPS 可以被认为是附着在革兰氏阴性细菌的外膜上。 三个区域：脂质A成分、核心寡糖和O抗原。 显示出物种与物种之间最大的差异，并且除了脂质 A 部分外，它还发挥着重要作用 在毒力上。 同样，荚膜多糖包围致病性革兰氏阳性菌和革兰氏阳性菌。 阴性细菌是抵抗宿主免疫系统的第一道防线。 重量多糖通过伪装细胞表面成分发挥作用，这些成分通常会引起 荚膜多糖中的糖通常通过附着一个修饰物而被修饰。 多种部分，包括 O-甲基氨基磷酸酯基团，已被证明参与 宿主入侵和噬菌体识别此外，一些荚膜多糖含有nonulosonic。 酸，九碳单糖，与毒力有关。 MIRA 奖项的智力目标有三个：(1) 扩展我们目前对 参与 O-抗原糖生物合成的酶的结构和活性，(2) 提供 了解 O-甲基氨基磷酸酯基团生物合成的分子框架 空肠弯曲菌，以及（3）探索参与空肠弯曲菌的酶的结构和功能 从鲍曼不动杆菌（一种已放入 世界卫生组织将新抗生素的开发列为“关键”类别。 所使用的技术包括 X 射线晶体学、定点诱变和动力学分析。 重要的是，许多拟议调查的初步数据已经可用。 鉴于 LPS 和细菌致病性，我们的研究已经并将继续为细菌致病性研究提供信息。 荚膜多糖在细菌毒力中起着关键作用，要研究的酶可能 最终作为抗菌药物设计的目标。