Biochemistry and Structure of Lipid A Enzymes

脂质 A 酶的生物化学和结构

• 批准号: 9230402
• 负责人: Pei Zhou
• 金额: $ 30.13万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9230402
• 关键词: Adverse effects; Alzheimer' s Disease; Amyloid; Anabolism; Antibiotics; Antimicrobial Resistance; Attenuated; Attenuated Vaccines; Bacteria; Binding; Biochemical; Biochemistry; Biogenesis; Biomedical Engineering; Calcineurin; Catalysis; Chlamydia; Chlamydia trachomatis; Complement; Complex; Crystallization; Cytosol; Detergents; Development; Diphosphates; Disaccharides; Enzymes; Escherichia coli; Excision; Family; Francisella; Francisella tularensis; Future; Genomic Library; Glucosamine; Goals; Gram-Negative Bacteria; Haemophilus influenzae; Health; Helicobacter; Helicobacter pylori; Hospitals; Human; Hydrolase; Hydrophobicity; Hypersensitivity; Immune System Diseases; Immune response; Immunity; Immunotherapeutic agent; In Vitro; Individual; Infection; Inflammatory; Investigation; Knowledge; Life; Lipid A; Lipids; Lipopolysaccharides; Malignant Neoplasms; Malignant neoplasm of cervix uteri; Membrane; Modification; Molecular; Molecular Probes; Multi-Drug Resistance; Mus; Mutagenesis; Neurodegenerative Disorders; Open Reading Frames; Orthologous Gene; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Peptides; Peripheral; Phagocytes; Phosphoric Monoester Hydrolases; Play; Prevention; Production; Proteobacteria; Public Health; Reporting; Role; Salmonella; Salmonella infections; Septic Shock; Structure; Surface; Vaccine Adjuvant; Variant; Virulence; Virulence Factors; base; cancer therapy; environmental change; enzyme pathway; human disease; improved; inhibitor/antagonist; inorganic phosphate; insight; lipid X; member; membrane biogenesis; monolayer; mutant; nervous system disorder; novel; novel therapeutics; pathogen; periplasm; public health relevance; pyrophosphatase; response; small molecule inhibitor; structural biology; sugar; virtual

 DESCRIPTION (provided by applicant): Lipid A, the hydrophobic membrane anchor of lipopolysaccharide, is a glucosamine-based saccharolipid that constitutes the outer monolayer of the outer membrane of Gram-negative bacteria and protects bacteria from the external damage of detergents and antibiotics. It is also the active component of lipopolysaccharide that causes life-threatening Gram-negative septic shock. Lipid A is synthesized by nine enzymes of the Raetz pathway in E. coli. The first six enzymes of lipid A biosynthesis are required for the viability of virtually all Gram-negative bacteria and are novel antibiotic targets. After lipid A i generated, it is flipped from the cytosolic surface of the inner membrane to the periplasmic surface, where it can be further transformed by lipid A modification enzymes that are specific to individual bacterial species. These modifications help bacteria evade the host immune response, adapt to environmental changes, and generate altered lipid A molecules that display diverse bioactivities. Although detailed structural analyses of several lipid A biosynthetic and modification enzymes have been carried out, providing rich information for structure-aided inhibitor development, others require further characterization. This proposal focuses on biochemical and structural studies of the essential lipid A biosynthetic enzymes that convert UDP-diacylglucosamine (UDP-DAGn) to 2,3- diacyl-GlcN-1-P (lipid X) and the lipid A modification enzyme LpxE that is important for bacterial virulence and production of monophosphorylated lipid A (MPLA), a widely used immunotherapeutic agent. These studies are expected to generate fundamental insights into the structure and mechanism of lipid A enzymes as well as the biogenesis and function of the bacterial outer membrane, and ultimately contribute to the development of novel therapeutics to improve human health.

 说明(申请人提供)：脂类A是脂多糖的疏水性膜锚，是一种以氨基葡萄糖为基础的糖脂，构成革兰氏阴性细菌外膜的外单分子层，保护细菌免受洗涤剂和抗生素的外部损害。它也是脂多糖的活性成分，会导致危及生命的革兰氏阴性败血症休克。在大肠杆菌中，类脂A由Raetz途径的九种酶合成。脂质A生物合成的前六种酶是几乎所有革兰氏阴性细菌生存所必需的，是新的抗生素靶标。在脂质A I产生后，它从内膜的胞浆表面翻转到周质表面，在那里它可以被个别细菌物种特有的脂质A修饰酶进一步转化。这些修饰帮助细菌逃避宿主免疫反应，适应环境变化，并产生显示不同生物活性的改变的类脂A分子。尽管已经对几种脂质A生物合成和修饰酶进行了详细的结构分析，为结构辅助抑制剂的开发提供了丰富的信息，但其他酶还需要进一步的表征。这项建议侧重于将UDP-二酰氨基葡萄糖(UDP-DAGn)转化为2，3-二酰基-GlcN-1-P(LipX)的必需LipA生物合成酶的生化和结构研究，以及LpxE的LpxE，LpxE对细菌毒力和单磷酰化LpA(一种广泛使用的免疫治疗剂)的产生至关重要。这些研究有望对A类脂酶的结构和机制以及细菌外膜的生物发生和功能产生基础的见解，并最终有助于开发新的治疗方法来改善人类健康。