Assembly and export of mycobacterial lipoglycans

分枝杆菌脂聚糖的组装和输出

• 批准号: 10426356
• 负责人: Mary Jackson
• 金额: $ 66.35万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-10 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10426356
• 关键词: Abbreviations; Actinobacteria class; Acylation; Acyltransferase; Anabolism; Bacillus; Biochemical; Biochemistry; Biogenesis; Biological; Biological Assay; Blood capillaries; Cell membrane; Cell model; Cell surface; Cells; Chemicals; Complex; Corynebacterium glutamicum; Development; Diglycerides; Disease; Dissection; Electrophoresis; Enzymes; Event; Face; Family; Fatty Acids; Genetic; Genomics; Genus Mycobacterium; Glycerol; Glycolipids; Goals; HIV/TB; Human Development; Hydroxyl Radical; Immune response; Inositol; Intervention; Investigation; Knowledge; Laboratories; Lead; Leprosy; Ligands; Lipopolysaccharides; Location; Mannans; Mannose; Mannosides; Mannosyltransferases; Mass Spectrum Analysis; Membrane; Metabolic; Molecular; Mycobacterium tuberculosis; Nature; Nomenclature; Open Reading Frames; Organism; PIM1 gene; Pathogenesis; Pathway interactions; Phagocytes; Pharmaceutical Preparations; Phenotype; Phosphatidylinositols; Physiology; Play; Prevalence; Prevention; Process; Recombinants; Research; Resort; Role; Side; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Streptomyces coelicolor; Structure; Structure-Activity Relationship; Therapeutic Intervention; Thin Layer Chromatography; Time; Tuberculosis; Vaccines; Vertebral column; Virulence Factors; Xylose; acyl group; arabinogalactan; base; cell envelope; co-infection; deoxycholate; design; drug development; enzyme activity; enzyme pathway; epimerase; extensive drug resistance; genetic manipulation; glycosyltransferase; immunoregulation; inhaled nitric oxide; interest; lipoarabinomannan; lipomannan; mutant; mycobacterial; novel; novel therapeutics; pathogen; phosphatidylinositol mannoside; prophylactic; targeted treatment; treatment strategy; tuberculosis drugs

Abstract Phosphatidylinositol mannosides (PIM) and their multiglycosylated counterparts, lipomannan (LM) and lipoarabinomannan (LAM), are complex glycolipids and lipoglycans found in the cell envelopes of all mycobacterial species. They play various essential although poorly defined roles in mycobacterial physiology and are important immunomodulatory molecules in the course of tuberculosis and leprosy as well as key ligands promoting the entry of mycobacteria and their survival within phagocytic and non-phagocytic cells. Although much progress has been made over the last 25 years in elucidating the structures and biosynthesis of these molecules, fundamental questions remain about the pathways leading to their biosynthesis and translocation to the cell surface. Furthermore, while the pleiotropic biological activities displayed by purified PIM, LM and LAM in cellular models suggest that they play important roles in pathogenesis, studies aimed at validating this assumption and precisely delineating their contribution to host-pathogen interactions when carried by intact bacilli are still limited by the paucity of mutants deficient in well-defined aspects of the biosynthesis and export of these molecules that are available. We propose to pursue structural, genetic and biochemical studies toward a complete definition of the structure (Aim 1), biosynthesis (Aim 2) and export (Aim 3) of PIM, LM and LAM. Completing our understanding of PIM, LM and LAM biogenesis, in addition to providing fundamental knowledge about the biochemistry of Mycobacterium tuberculosis (Mtb), is expected to lead to the discovery of essential enzymes and transporters which, much like the arabinosyltransferases of the Emb family and the epimerase DprE1, could provide new opportunities for anti-tuberculosis drug development. The availability of recombinant strains accumulating structurally defined biosynthetic precursors will facilitate structure-function relationship studies, and that of defined Mtb mutants deficient in various aspects of PIM, LM and LAM synthesis will allow a precise assessment of the contribution of these molecules to the immunopathogenesis of tuberculosis. Abbreviations: AG, arabinogalactan; AM, arabinomannan; AcylT, acyltransferase; Araf, arabinofuranosyl; AraT, arabinosyltransferase; CZE, capillary zone electrophoresis; DOC, deoxycholate; GT, glycosyltransferase; Ino, myo-Inositol; LAM, lipoarabinomannan; LM, lipomannan; LPS, lipopolysaccharide; MALDI-TOF, Matrix-Assisted Laser desorption/ionization time of flight; Manp, mannopyranosyl; ManT, mannosyltransferase; MPI, mannosylated phosphatidylinositol; MS, mass spectrometry; MTX, methyl-thio-xylose; ORF, open reading frame; OM, outer membrane; PIM, phosphatidyl-myo-inositol mannosides; TLC, thin-layer chromatography. Nomenclature: PIM is used to describe the global family of phosphatidylinositol mannosides that carries one to four fatty acids (attached to the glycerol, inositol and/or mannose) and one to six mannose residues. In AcXPIMY, x refers to the number of acyl groups esterified to available hydroxyls on the mannose or myo-inositol residues, y refers to the number of mannose residues; e.g. Ac1PIM1 corresponds to the phosphatidylinositol mono-mannoside PIM1 carrying two acyl groups attached to the glycerol (the diacylglycerol substituent) and one acyl group esterified to the mannose residue.

抽象的 磷脂酰肌醇甘露糖苷 (PIM) 及其多糖基化对应物、脂甘露聚糖 (LM) 和 脂阿拉伯甘露聚糖 (LAM) 是一种复杂的糖脂和脂聚糖，存在于所有细胞的细胞膜中。 分枝杆菌种类。它们在分枝杆菌生理学中发挥着各种重要但不明确的作用 是结核病和麻风病病程中重要的免疫调节分子，也是结核病和麻风病发病过程中的关键分子。 配体促进分枝杆菌的进入及其在吞噬细胞和非吞噬细胞内的存活。 尽管过去 25 年在阐明其结构和生物合成方面取得了很大进展 对于这些分子，关于其生物合成和合成途径的基本问题仍然存在 易位至细胞表面。此外，虽然纯化后显示出多效性生物活性 细胞模型中的 PIM、LM 和 LAM 表明它们在发病机制中发挥着重要作用，研究旨在 验证这一假设并准确描述它们对宿主-病原体相互作用的贡献 完整的杆菌所携带的细菌仍然受到缺乏突变体的限制，这些突变体在明确的方面存在缺陷。 这些可用分子的生物合成和输出。 我们建议进行结构、遗传和生化研究，以获得结构的完整定义 PIM、LM 和 LAM 的（目标 1）、生物合成（目标 2）和输出（目标 3）。完成我们对PIM的理解， LM 和 LAM 生物发生，除了提供有关生物化学的基础知识 结核分枝杆菌（Mtb）有望导致必需酶和转运蛋白的发现 它与 Emb 家族的阿拉伯糖基转移酶和差向异构酶 DprE1 非常相似，可以提供新的 抗结核药物开发的机遇。重组菌株的可用性不断积累 结构明确的生物合成前体将促进结构与功能关系的研究， 确定的 Mtb 突变体在 PIM、LM 和 LAM 合成的各个方面都存在缺陷，这将允许精确的 评估这些分子对结核病免疫发病机制的贡献。 缩写： AG，阿拉伯半乳聚糖； AM，阿拉伯甘露聚糖； AcylT，酰基转移酶；阿拉夫，阿拉伯呋喃糖基； AraT，阿拉伯糖基转移酶； CZE，毛细管 区带电泳； DOC，脱氧胆酸盐； GT，糖基转移酶； Ino，肌醇； LAM，阿拉伯脂甘露聚糖； LM，脂甘露聚糖；脂多糖, 脂多糖； MALDI-TOF，基质辅助激光解吸/电离飞行时间； Manp，吡喃甘露糖基；曼特, 甘露糖基转移酶； MPI，甘露糖化磷脂酰肌醇； MS，质谱； MTX，甲硫基木糖； ORF，开放阅读 框架; OM，外膜； PIM，磷脂酰肌醇甘露糖苷； TLC，薄层色谱法。 命名法： PIM 用于描述磷脂酰肌醇甘露糖苷的全球家族，其携带一到四个脂肪酸（附着在甘油、 肌醇和/或甘露糖）和一到六个甘露糖残基。在 AcXPIMY 中，x 是指酯化成可用的酰基数 甘露糖或肌醇残基上的羟基，y是指甘露糖残基的数目；例如Ac1PIM1 对应于 磷脂酰肌醇单甘露糖苷 PIM1 带有两个连接到甘油（二酰基甘油取代基）上的酰基和一个 酰基与甘露糖残基酯化。