Structural and Biochemical Studies of LpxC Inhibition

LpxC 抑制的结构和生化研究

• 批准号: 8033181
• 负责人: Pei Zhou
• 金额: $ 38.22万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 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/8033181
• 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; Health; 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; scaffold

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（由申请人提供）：脂质A（内毒素）是一种基于葡萄糖的糖粉，构成了革兰氏阴性细菌的外膜的外膜外层；它也是脂多糖的活跃成分，会导致威胁生命的革兰氏阴性败血性休克。脂质A生物合成是在几乎所有革兰氏阴性生物中保守的必要途径。 UDP-3-O-（酰基） - N-乙酰基葡萄糖胺脱乙酰基酶（LPXC）催化脂质的生物合成。因为LPXC是脂质A生物合成中必不可少的酶，并且与任何已知的哺乳动物蛋白质共享序列或结构同源性，因此它是设计新型抗生素的绝佳靶标。实际上，已经发现了几种有效的LPXC抑制剂，显示出各种程度的抗生素活性。一些最近发现的化合物还显示了时间依赖性的LPXC抑制作用，该特性对于抗生素非常可取，因为酶/抑制剂复合物的半衰期很长。不同LPXC直系同源物之间可能存在很大程度的局部结构变化。大肠杆菌LPXC的许多有效抑制剂对发散的LPXC酶相对不活跃，尤其是铜绿假单胞菌（铜绿假单胞菌），这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，对抗多药的革兰氏阴性病原体（如calcocaceter calcoaceticus和burkholderia cepacia）无效。这种不寻常的抑制剂特异性以及缺乏各种LPXC/抑制剂复合物的结构信息，从而严重阻碍了现有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含LPXC靶向抗生素的抑制作用和抑制范围。该目标将通过与代表性LPXC抑制剂复合物以及基于结构见解的新型化合物的设计，合成和评估的详细结构和生化研究来实现。公共卫生相关性缺乏对多药耐药的革兰氏阴性病原体的有效治疗，包括对所有临床上可用的抗生素具有抗药性的假单胞菌或杆菌菌株，这强调了对抗生素的紧迫需求，具有新颖的作用机制。我们提出的对LPXC的结构和生化研究是脂质A生物合成中的必不可少的酶，以及革兰氏阴性细菌的新型抗生素靶标，将揭示分子基础抑制剂特异性和时间依赖性抑制。我们的研究已经受益匪浅，并将继续促进针对革兰氏阴性病原体的广泛的有效LPXC抗生素的开发。