Regulation of lipid metabolism in bacteria

细菌脂质代谢的调节

• 批准号: 8389581
• 负责人: Charles O Rock
• 金额: $ 69.05万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-12-01 至 2014-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8389581
• 关键词: Accounting; Acyl Carrier Protein; Acyltransferase; Anti-Bacterial Agents; Antibiotics; Assimilations; Bacteria; Bacterial Physiology; Biochemical; Biochemical Genetics; Biological Factors; Clinic; Development; Drug Targeting; Drug resistance; Ensure; Enzymes; Equilibrium; Escherichia coli; Fatty Acids; Gene Expression; Goals; Gram-Negative Bacteria; Gram-Positive Bacteria; Homeostasis; Host Defense Mechanism; Human; Individual; Infection; Intoxication; Lead; Ligands; Lipids; Literature; Measures; Medical; Membrane; Membrane Lipids; Metabolic; Metabolism; Modeling; Molecular; Monitor; Organism; Outcome Study; Oxidoreductase; Pathway Analysis; Pathway interactions; Phospholipids; Physiological; Process; Proteins; Protons; Reaction; Regulation; Request for Proposals; Research; Route; Skin; Staphylococcus aureus; Streptococcus pneumoniae; Structure; Substrate Specificity; System; Technology; Therapeutic; Toxic effect; Transcriptional Regulation; Unsaturated Fatty Acids; Voice; Work; antimicrobial; base; combat; design; drug discovery; extracellular; fatty acid biosynthesis; fatty acid metabolism; fatty acid synthase II; inhibitor/antagonist; interest; lipid biosynthesis; lipid metabolism; metabolomics; novel; novel therapeutics; pathogen; programs; public health relevance; research study

DESCRIPTION (provided by applicant): The long term goal of the research program is to understand the biochemical and genetic regulation of lipid metabolism and membrane homeostasis in bacteria. The basic blueprint for bacterial membrane lipid biosynthesis is established by decades of research with Escherichia coli. However, there are numerous and significant differences in lipid metabolism between Gram-positive and Gram-negative bacteria. Gram-positive bacteria have unique enzymes for fatty acid biosynthesis, use a different activated fatty acid intermediate and acyltransferase system, and use transcriptional regulators that are distinctly different from E. coil. The medical significance of understanding this vital facet of intermediary metabolism has focused the research plan on investigating fatty acid and phospholipid synthesis in two important human pathogens: Staphylococcus aureus and Streptococcus pneumoniae. These organisms represent two major branches of lipid metabolic diversity in Gram-positive bacteria. Because type II fatty acid synthesis is a vital facet of bacterial physiology, there is considerable interest in the therapeutic potential of pathway inhibitors. However, Gram-positive bacteria can utilize extracellular fatty acids and may circumvent pathway inhibitors by the acquisition of host-derived fatty acids. One aim is to identify and characterize the unknown enzymes in the pathway for the incorporation of exogenous fatty acids in Gram-positive bacteria. A detailed biochemical understanding of this process will allow us to determine if exogenous fatty acids can overcome fatty acid synthesis inhibitors. The second aim is to determine the mechanism for skin antibacterial defense by fatty acid intoxication. Fatty acids have been known for decades to be a component of the innate defense system and toxic to Gram-positive bacteria. We propose a completely new mechanism of action for skin fatty acids. Fatty acid intoxication arises from the inability of specific structures to be utilized by the enzymes of lipid metabolism resulting in the accumulation of intracellular fatty acids and the collapse of the membrane proton gradient. A mechanistic understanding of this important host defense mechanism will provide a rational basis for designing novel fatty acid structures with increased efficacy. The final goal is to identify the regulatory factors and target proteins responsible for the tight biochemical control of membrane lipid biosynthesis in Gram-positive pathogens. Fatty acid synthesis is stringently regulated at the biochemical level to ensure a balanced membrane lipid composition. A system- oriented metabolomics approach will be developed to study pathway regulation. The analysis of pathway intermediates following physiological perturbations will identify the candidate regulatory ligands and target enzymes that will be biochemically characterized. The systematic analytical workflow we will develop can be applied to study any bacterium, and the outcome of these studies in pathogens will suggest a unique approach to developing new therapeutics. Structural mimics of the key regulatory ligand(s) could be developed to block membrane lipid biosynthesis.

描述（由申请人提供）：研究计划的长期目标是了解细菌中脂质代谢和膜稳态的生化和遗传调节。细菌膜脂质生物合成的基本蓝图是通过与大肠杆菌进行数十年研究建立的。但是，革兰氏阳性和革兰氏阴性细菌之间的脂质代谢存在许多显着差异。革兰氏阳性细菌具有用于脂肪酸生物合成的独特酶，使用不同活化的脂肪酸中间体和酰基转移酶系统，并使用与E. coil明显不同的转录调节剂。理解中介代谢的这一重要方面的医学意义重点是研究计划在两种重要的人类病原体中研究脂肪酸和磷脂合成：金黄色葡萄球菌和肺炎链球菌。这些生物代表了革兰氏阳性细菌中脂质代谢多样性的两个主要分支。因为II型脂肪酸合成是细菌生理学的重要方面，所以人们对途径抑制剂的治疗潜力具有很大的兴趣。然而，革兰氏阳性细菌可以利用细胞外脂肪酸，并通过获取宿主衍生的脂肪酸来绕过途径抑制剂。一个目的是识别和表征未知的酶在革兰氏阳性细菌中掺入外源性脂肪酸的途径中。对这一过程的详细生化理解将使我们能够确定外源脂肪酸是否可以克服脂肪酸合成抑制剂。第二个目的是通过脂肪酸中毒来确定皮肤抗菌防御的机制。数十年来，脂肪酸一直是先天防御系统的组成部分，并使革兰氏阳性细菌有毒。我们提出了一种全新的皮肤脂肪酸作用机理。脂肪酸中毒是由于脂质代谢的酶无法利用的特定结构而产生的，从而导致细胞内脂肪酸的积累和膜质子梯度的崩溃。对这种重要的宿主防御机制的机械理解将为设计新颖的脂肪酸结构具有提高功效而提供合理的基础。最终目标是确定负责蛋白质的调节因素和靶蛋白，以使革兰氏阳性病原体中膜脂质生物合成严格的生化控制。脂肪酸合成在生化水平上受到严格调节，以确保平衡的膜脂质组成。将开发以系统为导向的代谢组学方法来研究途径调节。生理扰动后途径中间体的分析将确定候选调节配体和靶酶，这些酶将在生化上表征。我们将开发的系统分析工作流可以用于研究任何细菌，这些病原体中这些研究的结果将提出一种开发新疗法的独特方法。可以开发关键调节配体的结构模拟物来阻断膜脂质生物合成。