New chemoenzymatic methods for synthesizing complex carbohydrates

合成复杂碳水化合物的新化学酶法

• 批准号: 8737279
• 负责人: Xi Chen
• 金额: $ 29.6万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-20 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8737279
• 关键词: Acetylglucosamine; Affect; Antithrombins; Binding; Biological; Biological Assay; Carbohydrates; Chemicals; Coagulants; Collaborations; Complex; Crystallography; Development; Enzymes; Fibroblast Growth Factor; Funding; Goals; Heparan Sulfate Biosynthesis; Heparin; Heparitin Sulfate; Heterogeneity; Individual; Inorganic Sulfates; Lead; Learning; Length; Libraries; Location; Malignant Neoplasms; Methods; Modification; Monosaccharides; Muscle Form Glycogen Phosphorylase; Mutagenesis; Nature; Oligosaccharides; Pasteurella multocida; Pattern; Phosphorylases; Phosphotransferases; Play; Polysaccharides; Process; Production; Proteins; Reagent; Regulation; Role; Structural Biologist; Structure; Structure-Activity Relationship; Testing; Text; Therapeutic; Therapeutic Studies; Time; Unspecified or Sulfate Ion Sulfates; Uridine Diphosphate Sugars; Uronic Acids; Variant; Viral; abstracting; amino group; analog; biological systems; carbohydrate analog; chemical synthesis; heparosan synthase; human RPL29 protein; inorganic phosphate; mimetics; mutant; novel; novel therapeutics; sugar; sulfation; tool

Enter the text here that is the new abstract information for your application. This section must be no longer than 30 lines of text. Complex carbohydrates play important roles in biological systems. However, it is very difficult to obtain these structures in pure homogeneous forms either by isolation from nature or by chemical synthesis. Therefore, the detailed structure-activity relationship is usually not clear, even for well known compounds with important functions. The ultimate goal of this project is to develop novel chemoenzymatic synthetic methods to efficiently obtain synthetically challenging carbohydrates and analogs in amounts large enough for structural characterization, functional studies, and therapeutic applications. For the current funding period, we are focusing on the synthesis of heparin and heparan sulfate (HS) oligosaccharide analogs. We hypothesize that N-sulfated analogs can mimic heparin/HS oligosaccharides for binding to their target proteins and have similar bioactivities. In addition, the N-sulfated analogs with synthetically controllable N- sulfation patterns can be powerful tools to probe the important roles of individual sulfations and provide critical information about individual roles of related O-sulfation in functional heparin/HS oligosaccharides. To test this hypothesis, we propose to synthesize a list of N3-modified GlcNAc or GlcA derivatives that can be used as substrates for UDP-GlcNAc and UDP-GlcA biosynthetic enzymes and heparosan synthases for producing N3- containing oligosaccharides. The azido group can then be reduced to an amino group and followed by chemical N-sulfation to provide N-sulfated analogs of heparin/HS oligosaccharides for testing their activities. Four specific aims are 1) chemical synthesis of N-acetylglucosamine (GlcNAc) and uronic acid derivatives as monosaccharide precursors; 2) synthesis of UDP-GlcNAc, UDP-uronic acids, and their derivatives; 3) enzymatic synthesis of heparin and heparan sulfate oligosaccharide analogs using heparosan synthases; 4) structure-activity relationship (SAR) studies using heparin/heparan sulfate-binding proteins. In addition, we will collaborate with our colleague and long-time collaborator, Prof. Andrew Fisher, an expert structural biologist with special expertise on protein crystal structural studies to solve the crystal structures of heparosan synthases, which are important enzymes for the assembly of heparin/HS polysaccharide structures. The information learned and the products obtained will facilitate the discovery and development of new therapeutics.

在此处输入文本，该文本是您的应用程序的新摘要信息。此部分不得超过 30 行 文本。 复杂碳水化合物在生物系统中发挥着重要作用。然而，获得这些却非常困难 通过从自然界分离或通过化学合成而获得纯均质形式的结构。因此， 详细的结构-活性关系通常不清楚，即使对于具有重要意义的众所周知的化合物也是如此。 功能。该项目的最终目标是开发新颖的化学酶合成方法，以有效地 获得合成上具有挑战性的碳水化合物和类似物，其数量足以用于结构 表征、功能研究和治疗应用。在当前的资助期内，我们 专注于肝素和硫酸乙酰肝素（HS）寡糖类似物的合成。 我们假设 N-硫酸化类似物可以模仿肝素/HS 寡糖与其靶标结合 蛋白质并具有相似的生物活性。此外，具有合成可控N-的N-硫酸化类似物 硫酸化模式可以成为探测单个硫酸化的重要作用的强大工具，并提供关键的信息 有关功能性肝素/HS 寡糖中相关 O-硫酸化的各个作用的信息。为了测试这个 假设，我们建议合成一系列 N3 修饰的 GlcNAc 或 GlcA 衍生物，可用作 UDP-GlcNAc 和 UDP-GlcA 生物合成酶和乙酰肝素合成酶的底物，用于生产 N3- 含有低聚糖。然后可以将叠氮基还原为氨基，然后 化学 N-硫酸化，提供肝素/HS 寡糖的 N-硫酸化类似物，用于测试其活性。 四个具体目标是 1) N-乙酰氨基葡萄糖 (GlcNAc) 和糖醛酸衍生物的化学合成 单糖前体； 2) UDP-GlcNAc、UDP-糖醛酸及其衍生物的合成； 3） 使用乙酰肝素合酶酶促合成肝素和硫酸乙酰肝素寡糖类似物； 4） 使用肝素/硫酸乙酰肝素结合蛋白进行构效关系 (SAR) 研究。此外，我们将 与我们的同事和长期合作者、结构生物学专家 Andrew Fisher 教授合作 具有蛋白质晶体结构研究的特殊专业知识，可解决heparosan的晶体结构 合酶，是组装肝素/HS多糖结构的重要酶。这 学到的信息和获得的产品将促进新产品的发现和开发 疗法。