3-Ketoacyl ACP Synthase III: A Novel Antibiotic Target

3-酮脂酰 ACP 合酶 III：新型抗生素靶点

• 批准号: 7095655
• 负责人: KEVIN A REYNOLDS
• 金额: $ 20.71万
• 依托单位: PORTLAND STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7095655
• 关键词: X ray crystallography; acetyl coA; active sites; acyl carrier protein; antibacterial agents; antibiotics; antiinfective agents; antimalarial agents; catalyst; chemical binding; drug design /synthesis /production; drug interactions; drug screening /evaluation; enzyme inhibitors; enzyme structure; enzyme substrate; fatty acid biosynthesis; fatty acid synthase; fluorimetry; nuclear magnetic resonance spectroscopy; polymerase chain reaction; site directed mutagenesis; stop flow technique

DESCRIPTION (provided by applicant): Fatty acid biosynthesis by a type II dissociated fatty acid synthase (FAS) is a fundamental and indispensable metabolic pathway in many organisms, including bacteria and parasites. The distinctions between this and the multifunctional type I FAS of higher organisms offer a selective target for the design of novel antibacterial and antiparasitic agents, needed to combat the resurgence of antibiotic-resistant bacteria and multidrug-resistant forms of the malaria-causing plasmodial parasites. In all type II FAS systems, the initial condensation step is carried out by 3-ketoacyl acyl carrier protein (ACP) synthase III (KASIII, FabH), which catalyzes the condensation of an acyl CoA substrate with malonyl ACP to generate a 3-ketoacyl ACP product. FabH also appears to play a key role in regulation of fatty acid biosynthesis and is not targeted by any current drugs, making it a particularly attractive new target for drug design. The long-term objective of our work is to understand the structural and mechanistic bases of FabH that define its physiological roles and to use this information to generate novel potent and selective inhibitors. This grant will extend our study of FabH enzymes from organisms such as Escherichia coil and Staphylococcus aureus, which initiate de novo fatty acid biosynthesis from different short chain acyl CoA substrates, and Mycobacterium tuberculosis, which uses FabH to initiate mycolate biosynthesis from long chain acyl CoA substrates. Mutational analyses and crystallography will be used to investigate the differing substrate and inhibitor specificities of these enzymes. In conjunction with ongoing crystallographic, molecular modeling and kinetic analyses, the mode of binding of 1,2-dithiole-3-one and related compounds which are potent novel active site FabH inhibitors, and a second series of inhibitors that appear to bind in the FabH phosphopantetheine binding channel, will be investigated. The information gathered from these studies will be used to design, synthesize and ultimately test inhibitors, which maximize interactions with both active site residues and those in either the acyl-binding pocket or phosphopantetheine-binding channel. Such compounds should have enhanced activity and selectivity against FabH and be powerful new lead compounds for development of novel antibacterial and antiparastitic/antimalarial drugs.

描述(由申请人提供)：由II型解离脂肪酸合成酶(Fas)合成的脂肪酸是包括细菌和寄生虫在内的许多生物体中基本和不可或缺的代谢途径。这与高等生物体的多功能I型Fas之间的区别为设计新的抗菌和抗寄生虫剂提供了一个有选择的靶点，这是抗击抗药性细菌和导致疟疾的疟原虫的多重抗药性形式复兴所必需的。在所有II型Fas系统中，初始缩合步骤是由3-酮酰基载体蛋白(ACP)合成酶III(KASIII，FabH)进行的，该酶催化酰基辅酶A底物与丙二酰ACP缩合生成3-酮酰基ACP产物。FabH似乎还在调节脂肪酸生物合成方面发挥关键作用，目前任何药物都不针对它，使其成为药物设计的一个特别有吸引力的新靶点。 我们工作的长期目标是了解定义其生理作用的FabH的结构和机制基础，并利用这些信息来产生新的、有效的和选择性的抑制剂。这笔拨款将扩大我们对来自生物体的FabH酶的研究，这些生物体包括从不同的短链酰基CoA底物启动从头合成脂肪酸的Escherichia Cos和金黄色葡萄球菌，以及使用FabH从长链Acyl CoA底物启动Mycolate生物合成的结核分枝杆菌。突变分析和结晶学将用于研究这些酶的不同底物和抑制剂的特异性。结合正在进行的结晶学、分子模拟和动力学分析，将研究1，2-二硫醇-3-酮和相关化合物的结合模式，这些化合物是有效的新型活性部位FabH抑制剂，以及第二系列似乎结合在FabH磷酸茶氨酸结合通道上的抑制剂。从这些研究中收集的信息将被用于设计、合成并最终测试抑制剂，这些抑制剂最大限度地与活性部位残基以及酰基结合口袋或磷酸精氨酸结合通道中的活性部位残基相互作用。这类化合物应具有更强的抗FabH活性和选择性，是开发新型抗菌、抗寄生虫/抗疟疾药物的强有力的新先导化合物。