Structural and Biochemical Studies of LpxC Inhibition

LpxC 抑制的结构和生化研究

基本信息

批准号：
7771757
负责人：
Pei Zhou
金额：
$ 38.61万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-06-15 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7771757
关键词：
Acinetobacter Acinetobacter calcoaceticus Anabolism Antibiotics Area Bacteria Binding Biochemical Biological Assay Burkholderia cepacia Catalysis Cause of Death Cell Culture Techniques Chemicals Commit Complex Development Diffusion Endotoxins Enzyme Inhibitor Drugs Enzyme Inhibitors Enzymes Escherichia coli Evaluation Genes Glucosamine Goals Gram-Negative Bacteria Growth Half-Life Human Individual Infection Investigation Lead Life Lipid A Lipopolysaccharides Membrane Modeling Molecular Molecular Conformation Morbidity - disease rate Multi-Drug Resistance Mus N-acetylglucosamine deacetylase Organism Orthologous Gene Pathway interactions Process Property Proteins Pseudomonas Pseudomonas aeruginosa Research Resistance Salmonella Septic Shock Shigella Specificity Testing Thermolysin Time Toxic effect Uridine Uridine Diphosphate Variant Yersinia Zinc antimicrobial bactericide base cystic fibrosis patients design effective therapy flexibility improved inhibitor/antagonist insight killings metalloenzyme monolayer mortality next generation novel pathogen public health relevance scaffold

项目摘要

DESCRIPTION (provided by applicant): Lipid A (endotoxin) is a glucosamine-based saccharolipid that constitutes the outer monolayer of the outer membrane of Gram-negative bacteria; it is also the active component of lipopolysaccharide that causes life-threatening Gram-negative septic shock. Lipid A biosynthesis is an essential pathway conserved in virtually all Gram-negative organisms. The committed step of lipid A biosynthesis is catalyzed by UDP-3-O-(acyl)-N-acetylglucosamine deacetylase (LpxC). Because LpxC is an essential enzyme in lipid A biosynthesis and does not share sequence or structural homology with any known mammalian protein, it is an excellent target for the design of novel antibiotics. Indeed, several potent LpxC inhibitors have been discovered that display various degrees of antibiotic activity. Some of the recently discovered compounds also show time-dependent LpxC inhibition, a property that is highly desirable for an antibiotic because of the long half-life of the enzyme/inhibitor complex. A significant degree of local structural variation is likely to exist among different LpxC orthologs. Many of the potent inhibitors of Escherichia coli LpxC are relatively inactive against divergent LpxC enzymes, especially that from Pseudomonas aeruginosa, the leading cause of death in cystic fibrosis patients. CHIR-090, the most potent LpxC inhibitor discovered to date, is ineffective against multidrug-resistant Gram-negative pathogens such as Acinetobacter calcoaceticus and Burkholderia cepacia. This unusual inhibitor specificity and the lack of structural information on various LpxC/inhibitor complexes together severely hinder further optimization of existing LpxC inhibitors. The overall goal of this proposal is (1) to understand the largely unknown molecular features of LpxC underlying inhibitor specificity and time-dependent inhibition and (2) to utilize this information to improve both the potency and spectrum of inhibition for the next generation of LpxC-targeting antibiotics. This goal will be achieved by detailed structural and biochemical studies of divergent LpxC orthologs in complex with representative LpxC inhibitors, and by design, synthesis and evaluation of novel compounds based on structural insights. PUBLIC HEALTH RELEVANCE The lack of effective treatment for multidrug-resistant Gram-negative pathogens, including strains of Pseudomonas or Acinetobacter that are resistant to all clinically available antibiotics, underscores the pressing need for antibiotics with novel mechanisms of action. Our proposed structural and biochemical studies of LpxC, an essential enzyme in lipid A biosynthesis and a novel antibiotic target of Gram-negative bacteria, will reveal the molecular basis underlying inhibitor specificity and time-dependent inhibition. Our studies have already benefited and will continue to facilitate the development of potent LpxC-targeting antibiotics against a broad spectrum of Gram-negative pathogens.

描述（申请人提供）：脂质A（内毒素）是一种基于葡萄糖胺的糖脂，构成革兰氏阴性菌外膜的外单层；它也是脂多糖的活性成分，可导致危及生命的革兰氏阴性败血性休克。脂质 A 生物合成是几乎所有革兰氏阴性生物体中保守的重要途径。脂质 A 生物合成的关键步骤由 UDP-3-O-(酰基)-N-乙酰葡糖胺脱乙酰酶 (LpxC) 催化。由于 LpxC 是脂质 A 生物合成中的必需酶，并且与任何已知的哺乳动物蛋白不具有序列或结构同源性，因此它是设计新型抗生素的绝佳靶点。事实上，已经发现了几种有效的 LpxC 抑制剂，它们表现出不同程度的抗生素活性。最近发现的一些化合物还表现出时间依赖性 LpxC 抑制作用，这种特性对于抗生素来说是非常理想的，因为酶/抑制剂复合物的半衰期很长。不同的 LpxC 直向同源物之间可能存在显着程度的局部结构变异。许多大肠杆菌 LpxC 的有效抑制剂对不同的 LpxC 酶相对无活性，尤其是来自铜绿假单胞菌的 LpxC 酶，铜绿假单胞菌是囊性纤维化患者死亡的主要原因。 CHIR-090 是迄今为止发现的最有效的 LpxC 抑制剂，对多重耐药革兰氏阴性病原体（如醋酸钙不动杆菌和洋葱伯克霍尔德菌）无效。这种不寻常的抑制剂特异性以及各种 LpxC/抑制剂复合物结构信息的缺乏共同严重阻碍了现有 LpxC 抑制剂的进一步优化。该提案的总体目标是（1）了解 LpxC 潜在的抑制剂特异性和时间依赖性抑制的很大程度上未知的分子特征，以及（2）利用这些信息来提高下一代 LpxC 的抑制效力和谱。 - 靶向抗生素。这一目标将通过对不同的 LpxC 直向同源物与代表性 LpxC 抑制剂复合物的详细结构和生化研究，以及基于结构见解的新型化合物的设计、合成和评估来实现。公共卫生相关性多重耐药革兰氏阴性病原体（包括对所有临床可用抗生素具有耐药性的假单胞菌或不动杆菌菌株）缺乏有效的治疗方法，这凸显了对具有新作用机制的抗生素的迫切需要。我们对 LpxC（脂质 A 生物合成中的一种必需酶和革兰氏阴性菌的新型抗生素靶点）提出的结构和生化研究将揭示抑制剂特异性和时间依赖性抑制的分子基础。我们的研究已经受益并将继续促进针对广谱革兰氏阴性病原体的有效 LpxC 靶向抗生素的开发。