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.

项目总结/摘要 细菌产生一系列种类繁多的碳水化合物大分子， 重要的生理作用。例如，脂多糖或LPS是复杂的糖缀合物， 附着在革兰氏阴性菌的外膜上从概念上讲，LPS可以被认为是 三个区域的术语：脂质A组分、核心寡糖和O-抗原。是O抗原 在不同物种间显示出最大的变异，并且除了脂质A部分外， 在毒力方面。 同样，围绕致病性革兰氏阳性菌和革兰氏阳性菌的荚膜多糖也是如此。 阴性细菌，作为抵御宿主免疫系统的第一道防线。这些高分子 重量多糖通过包裹细胞表面成分起作用，这些成分通常会引起 免疫反应通常，荚膜多糖中的糖通过连接糖链而被修饰。 包括O-甲基氨基磷酸酯基团的各种部分，其已被证明涉及 宿主入侵和噬菌体识别。此外，一些荚膜多糖含有非酮糖酸， 酸，九个碳基的单糖，这些单糖与毒力有关。 这个MIRA奖的智力目标有三个方面：（1）扩大我们目前对 参与O-抗原糖生物合成的酶的结构和活性，（2）提供一种 了解O-甲基氨基磷酸酯基团的生物合成的分子框架， 空肠弯曲菌，以及（3）探索参与的酶的结构和功能， 来自鲍氏不动杆菌的壬酮糖酸的生物合成，鲍氏不动杆菌是一种已被置于 “关键”类别由世界卫生组织为新抗生素的发展。 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具备。 我们的研究已经并将继续为细菌致病性的研究提供信息。鉴于LPS和 荚膜多糖在细菌毒力中起关键作用，待研究的酶可 最终成为抗微生物药物设计的目标。