Investigation of Novel Lipid A Structural Features

新型脂质A结构特征的研究

• 批准号: 6880609
• 负责人: MIDDLETON B HINCKLEY
• 金额: $ 4.4万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6880609
• 关键词: Leptospira; carbohydrate biosynthesis; disaccharides; endotoxins; enzyme activity; enzyme structure; expression cloning; glycolipids; immune response; lipid structure; lipopolysaccharides; mass spectrometry; membrane activity; methyltransferase; microorganism culture; monosaccharides; mutant; nuclear magnetic resonance spectroscopy; phosphomonoesterases; postdoctoral investigator; protein structure function; protein tyrosine kinase; tissue /cell culture; toll like receptor; transcription factor

DESCRIPTION (provided by applicant): In Gram-negative bacteria, lipid A constitutes the hydrophobic membrane anchor of the unique glycolipid lipopolysaccharide (LPS). It is essential for viability and serves as a potent immunostimulant by activating the TLR4 receptor. The structure and biosynthetic pathway of Escherichia coli lipid A has been extensively haracterized over the years. It is a hexaacylated disaccharide of glucosamine that is substituted at the 1- and 4'-positions with phosphate. Recently, the lipid A structure of the spirochete Leptospira interrogans has been solved, and two interesting features were revealed. The 1-phosphate is methylated, and the 4'-position is dephosphorylated. It has also been discovered that leptospiral LPS activates TLR2 in the innate immune response instead of TLR4. Understanding the enzymology of these modifications will not only facilitate the understanding of lipid A biosynthesis, but it will also provide new molecular insights into pathogenesis. Specifically, this proposal focuses on (l-ll) identification and characterization of the 1-methyltransferase and pie 4'-phosphatase; and (III) investigation of the effects these structural modifications have on the unique rTLR2-dependent immune response.

描述（由申请人提供）： 在革兰氏阴性菌中，脂质A构成独特糖脂脂多糖（LPS）的疏水膜锚。它对生存力至关重要，并通过激活TLR 4受体作为有效的免疫刺激剂。大肠杆菌类脂A的结构和生物合成途径已被广泛表征多年。它是葡萄糖胺的六酰化二糖，在1 '和4'-位被磷酸取代。最近，问号钩端螺旋体的脂质A结构已被解决，并揭示了两个有趣的功能。1-磷酸被甲基化，4 '-位被去磷酸化。还发现钩端螺旋体LPS在先天免疫应答中激活TLR 2而不是TLR 4。了解这些修饰的酶学不仅有助于了解脂质A的生物合成，而且还将为发病机制提供新的分子见解。具体地，该提议集中于（I-II）1-甲基转移酶和pie 4 '-磷酸酶的鉴定和表征;和（III）研究这些结构修饰对独特的rTLR 2依赖性免疫应答的影响。