Regulation of lipid metabolism in bacteria

细菌脂质代谢的调节

基本信息

批准号：
8037875
负责人：
Charles O Rock
金额：
$ 70.96万
依托单位：
ST. JUDE CHILDREN'S RESEARCH HOSPITAL
依托单位国家：
美国
项目类别：
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/8037875
关键词：
Accounting Acyl Carrier Protein Acyltransferase Anti-Bacterial Agents Antibiotics Assimilations Bacteria Bacterial Physiology Biochemical Biochemical Genetics Biological Factors Clinic Development Drug Delivery Systems 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 research study

项目摘要

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. PUBLIC HEALTH RELEVANCE: The rapid increase in infections caused by drug-resistant pathogens lends urgency to the development of effective new antibiotic countermeasures. Fatty acid biosynthesis is a vital facet of bacterial physiology that offers promising targets for the development of novel therapeutics. This research will provide a definitive answer regarding the suitability of membrane lipid synthesis in Gram-positive pathogens as a target for novel antibacterial drug discovery development.

描述（由申请人提供）：该研究项目的长期目标是了解细菌脂质代谢和膜稳态的生化和遗传调控。细菌膜脂质生物合成的基本蓝图是通过对大肠杆菌数十年的研究建立的。然而，革兰氏阳性菌和革兰氏阴性菌之间的脂质代谢存在许多显着差异。革兰氏阳性菌具有独特的脂肪酸生物合成酶，使用不同的活化脂肪酸中间体和酰基转移酶系统，并使用与大肠杆菌明显不同的转录调节因子。了解中间代谢这一重要方面的医学意义，使研究计划集中在研究两种重要的人类病原体：金黄色葡萄球菌和肺炎链球菌中的脂肪酸和磷脂合成。这些生物代表了革兰氏阳性菌脂质代谢多样性的两个主要分支。由于 II 型脂肪酸合成是细菌生理学的一个重要方面，因此人们对途径抑制剂的治疗潜力非常感兴趣。然而，革兰氏阳性细菌可以利用细胞外脂肪酸，并且可以通过获取宿主衍生的脂肪酸来规避途径抑制剂。目的之一是鉴定和表征革兰氏阳性菌中外源脂肪酸掺入途径中的未知酶。对这一过程的详细生化了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。第二个目的是确定脂肪酸中毒引起的皮肤抗菌防御机制。数十年来，脂肪酸一直被认为是先天防御系统的组成部分，并且对革兰氏阳性菌有毒。我们提出了一种全新的皮肤脂肪酸作用机制。脂肪酸中毒是由于脂质代谢酶无法利用特定结构，导致细胞内脂肪酸积累和膜质子梯度崩溃而引起的。对这一重要宿主防御机制的机械理解将为设计具有更高功效的新型脂肪酸结构提供合理的基础。最终目标是确定负责革兰氏阳性病原体膜脂生物合成严格生化控制的调节因子和靶蛋白。脂肪酸合成在生化水平上受到严格调控，以确保膜脂组成平衡。将开发一种面向系统的代谢组学方法来研究途径调控。对生理扰动后的途径中间体进行分析将确定候选调节配体和目标酶，并对其进行生化表征。我们将开发的系统分析工作流程可用于研究任何细菌，这些病原体研究的结果将为开发新疗法提供独特的方法。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。公共卫生相关性：耐药病原体引起的感染迅速增加，迫切需要开发有效的新型抗生素对策。脂肪酸生物合成是细菌生理学的一个重要方面，为新型疗法的开发提供了有希望的目标。这项研究将为革兰氏阳性病原体中膜脂合成作为新型抗菌药物发现开发的目标的适用性提供明确的答案。