LIPID A MODIFICATION SYSTEMS IN GRAM-NEGATIVE BACTERIA

革兰氏阴性细菌中的脂质 A 修饰系统

• 批准号: 7459771
• 负责人: Christian R Raetz
• 金额: $ 36.51万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7459771
• 关键词: Acyl Carrier Protein; Acyltransferase; Adjuvant; Anabolism; Animals; Appearance; Bacteria; Biochemical; Carbon; Chemical Structure; Clinical; Cloning; Cosmids; DNA; Development; Disaccharides; Endotoxins; Enteral; Enzymes; Epitopes; Escherichia coli; Facility Construction Funding Category; Fatty Acids; Figs - dietary; Genes; Genetic; Genomics; Glucosamine; Glycolipids; Gram-Negative Bacteria; Grant; Growth; Haemophilus influenzae; Helicobacter pylori; Human; Hybrids; Infection; Laboratories; Lead; Legionella pneumophila; Life; Lipid A; Lipids; Lipopolysaccharides; Minor; Modification; Monosaccharides; Nitrogen; Nodule; O Antigens; Organism; Pathogenesis; Pathway interactions; Phosphatidylinositols; Phosphoric Monoester Hydrolases; Phosphotransferases; Plants; Play; Porphyromonas gingivalis; Positioning Attribute; Reaction; Reagent; Reporting; Rhizobium; Role; Salmonella typhimurium; Sepsis; Staging; Standards of Weights and Measures; Structure; Structure-Activity Relationship; Surface; Symbiosis; System; Techniques; Transferase; analog; base; enzyme activity; galacturonic acid; genetic analysis; glycosyltransferase; inorganic phosphate; insight; interest; lipid A 4' -phosphatase; mutant; novel; pathogen; sugar

Lipopolysaccharides (LPSs) are remarkable glycolipids that comprise the outer surfaces of Gram-negative bacteria, including the symbiotic organism, Rhizobium leguminosamm. In Escherichia coli, the lipid A anchor of LPS is a hexa-acylated disaccharide of glucosamine, bearing phosphate moieties at positions 1 and 4'. The minimal LPS required for growth of E. coli consists of lipid A and two extra sugars. Emerging genomic sequences indicate that the enzymes that make lipid A in E. coli are present in most other Gram-negative bacteria. Lipid A (often termed endotoxin) is also the active component of LPS responsible for the clinical complications of Gram-negative sepsis. Minor modifications in the structure of lipid A can have profound effects on pathogenesis. Some lipid A analogs are actually potent endotoxin antagonists. Compared to E. coli, the chemical structures of the lipid A and core domains of/?, leguminosarum LPS are very unusual. R. leguminosarum lipid A lacks the 1 and 4' phosphates, but is modified with galacturonic acid at position 4'. It is acylated with a peculiar 28 carbon fatty acid, and contains 2-deoxy-2-aminogluconate in place of the proximal glucosamine. The structure of/?, leguminosarum LPS indicates the existence of novel enzymes for generating diverse lipid A and core species. It is now established that the first seven enzymes of lipid A I biosynthesis are in fact the same in E. coli and /?. leguminosarum. The differences arise in the later stages of the pathway. To date, enzymes identified as unique to /?. leguminosarum include a 4'-phosphatase that is also a phosphotransferase, a 1-phosphatase, a long chain acyltransferase with its own acyl carrier protein, and three distinct core glycosyltransferases. Characterization of the /?. leguminosarum system should provide insights into the functions of lipid A-like molecules, including special roles during symbiosis in plants, and affords the opportunity to create novel lipid A hybrids that may have interesting adjuvant or antagonist activities. Some structural features of/?, leguminosarum lipid A are seen in human pathogens. Legionella pneumophila lipid A i contains a C28 chain, while Porphyromonas gingivalis and Helicobacter pylori lipid A lack the 4' phosphate. | In the coming grant period, the specific aims are: I) cloning of the C28 acyltransferase of/?, leguminosarum; i II) analysis of the lipid A 4'-phosphatase/phosphotransferase, especially its ability to synthesize PtdIns-4-P; III) determination of the enzymatic basis for proximal unit diversity in /?. leguminosarum lipid A; and IV) i characterization of enzymes that incorporate the unique inner core sugars of/?, leguminosarum LPS.

脂多糖（LPS）是构成革兰氏阴性菌外表面的显著糖脂， 细菌，包括共生生物根瘤菌（Rhizobium leguminosamm）。在大肠杆菌中，脂质A锚 是葡糖胺的六酰化二糖，在位置1和4 '带有磷酸部分。的 E.大肠杆菌由脂质A和两种额外的糖组成。新兴基因组 序列表明E.大肠杆菌存在于大多数其他革兰氏阴性 细菌脂质A（通常称为内毒素）也是LPS的活性组分，其负责临床上的内毒素释放。 革兰氏阴性脓毒症的并发症脂质A结构中的微小修饰可以对脂质A的性质产生深远的影响。 对发病机制的影响。一些脂质A类似物实际上是有效的内毒素拮抗剂。 与E.大肠杆菌，脂质A和核心结构域的化学结构，豆科植物脂多糖 很不寻常R.豆科植物脂质A缺乏1和4'磷酸，但被半乳糖醛酸修饰， 位置4 '。它被一种特殊的28碳脂肪酸酰化，并含有2-脱氧-2-氨基葡萄糖酸 近端葡萄糖胺的浓度的结构，豆科植物脂多糖表明存在新的酶 用于产生不同的脂质A和核心物质。现在已经确定，脂质A的前七种酶 I的生物合成在E. coli和/？豆科植物差异出现在后期阶段 通路到目前为止，酶被鉴定为独特的/？。豆科植物包括4 ′-磷酸酶，其也是 磷酸转移酶，1-磷酸酶，具有其自身酰基载体蛋白的长链酰基转移酶，以及三种 不同的核心糖基转移酶。/？的表征。豆科植物系统应该提供 脂质A样分子的功能，包括在植物共生过程中的特殊作用，并提供了 这是产生可能具有令人感兴趣的佐剂或拮抗剂活性的新型脂质A杂合体的机会。一些 的结构特征，豆类真菌脂质A在人类病原体中可见。嗜肺军团菌脂质A i含有C28链，而牙龈卟啉单胞菌和幽门螺杆菌脂质A缺乏4'磷酸。 | 在即将到来的资助期内，具体目标是：I）克隆I？豆科植物; ii）分析脂质A 4 ′-磷酸酶/磷酸转移酶，特别是其合成PtdIns-4-P的能力; III）确定β中近端单位多样性的酶基础。豆科植物脂质A;和IV） i表征掺入β的独特内核糖的酶，豆科植物脂多糖

项目成果

Two-dimensional NMR spectroscopy and structures of six lipid A species from Rhizobium etli CE3. Detection of an acyloxyacyl residue in each component and origin of the aminogluconate moiety.

来自根瘤菌 CE3 的六种脂质 A 的二维核磁共振波谱和结构。

• DOI: 10.1074/jbc.m004009200
• 发表时间: 2000
• 期刊: The Journal of biological chemistry
• 作者: Que,NL;Ribeiro,AA;Raetz,CR
• 通讯作者: Raetz,CR

Periplasmic cleavage and modification of the 1-phosphate group of Helicobacter pylori lipid A.

幽门螺杆菌脂质 A 的 1-磷酸基团的周质裂解和修饰。

• DOI: 10.1074/jbc.m406480200
• 发表时间: 2004
• 期刊: The Journal of biological chemistry
• 作者: Tran,AnX;Karbarz,MarkJ;Wang,Xiaoyuan;Raetz,ChristianRH;McGrath,SaraC;Cotter,RobertJ;Trent,MStephen
• 通讯作者: Trent,MStephen

A facile enzymatic synthesis of uridine diphospho-[14C]galacturonic acid.

• DOI: 10.1006/abio.2000.4479
• 发表时间: 2000-04
• 期刊: Analytical biochemistry
• 影响因子: 2.9
• 作者: S. Basu;G. Dotson;C. Raetz