Natural product discovery and biosynthetic pathway elucidation from the human pathogen Legionella

项目摘要： 天然产物在生产生物体中发挥着重要的生物学作用， 药的来源。微生物天然产物的研究主要集中在环境生物上; 天然产物，特别是病原微生物产生的潜在小分子毒力因子， 更别说理解了军团菌感染引起军团菌病，它可以存在于其非肺炎 形式为庞蒂亚克热或急性肺炎形式为军团病。退伍军人症的死亡率 约10%是由于并发症，约25%是在医疗机构感染的。虽然如何 军团菌影响宿主的蛋白质效应物已被深入研究， 军团菌产生的代谢产物，这些天然产物在军团菌感染中的作用尚未得到充分研究。 拟议的工作将确定和表征潜在的生物活性天然产物从人类 病原体军团菌使用基因靶向方法鉴定潜在的新型金属酶， 不寻常的氧化重排产生N-亚硝基产物，这是过度保守的一种同系物 170个嗜肺军团菌亚种和另一个在德氏军团菌中保守的同源物， 发现了活性测定表明，该同系物催化类似的反应，但利用不同的底物。 基因邻域的生物信息学分析鉴定了生物合成基因簇（BGC）编码的 抗性酶和前药活化酶，可能指示潜在生物活性物质的生物合成。 代谢物。 目的1从军团菌的生物合成基因簇中鉴定天然产物及其生物活性， 找出潜在的致病因素目标2将启动两种酶的表征和机理研究 在BGC涉及的潜在药效团的生物合成，以促进理解和铺路 这类新的药效团产生酶对的抑制剂设计的方法。成功 这些目标的完成将确定潜在的生物活性天然产物的化学结构， 人类病原体军团菌。此外，还研究了参与潜在药效团生物合成的两个关键酶 也将被定性。这些天然产物的鉴定及其生物合成可能会揭示新的 毒力途径，可以针对打击军团菌感染。最终，整个工作流程将是 推广到研究其他新的天然产物或潜在的毒力因子从人类 病原体军团菌，以打击新兴的传染病，扩大池1）新类别的细胞毒性 候选药物/毒力因子和2）来自生物合成途径的新的抑制靶标。

Project Summary: Natural products play essential biological roles in producing organisms and have been a historically important source of medicines. Microbial natural products research has focused largely on environmental organisms; natural products, especially the potential small molecule virulent factor produced by pathogenic microbes, are much less understood. Legionella infection causes Legionellosis, which can be present in its non-pneumonic form as Pontiac fever or acute pneumonic form as Legionnaires’ disease. The fatality rate of legionnaires disease is about 10% due to complications and about 25% for those infected in the healthcare facility. While how the protein effectors of Legionella affect the host have been intensively studied, identifying the secondary metabolites Legionella produce and the roles these natural products play in Legionella infection are understudied. The proposed work will identify and characterize the potential bioactive nature products from the human pathogen Legionella. Using a gene-targeting approach to identify a potential novel metalloenzyme that catalyzes unusual oxidative rearrangement to generate the N-nitroso product, one homolog conserved in over 170 Legionella pneumophila subspecies and another homolog conserved in Legionella drozanskii was discovered. Activity assay shows this homolog catalyzes similar reactions but utilizes different substrates. Bioinformatic analysis of the gene neighborhood identifies the biosynthetic gene cluster (BGC) encodes resistance enzyme and a prodrug activating enzyme, possibly indicating the biosynthesis of potential bioactive metabolites. Aim 1 will identify the natural product and bioactivity from the biosynthetic gene cluster from Legionella to uncover the potential virulent factor. Aim 2 will initiate the characterization and mechanistic study of two enzymes in the BGC involving the biosynthesis of the potential pharmacophore to facilitate the understanding and pave the way for the inhibitor design of this new class of pharmacophore-producing enzyme pair. Successful completion of these aims will identify the chemical structure of the potential bioactive natural products from the human pathogen Legionella. In addition, two key enzymes involving the potential pharmacophore biosynthesis will also be characterized. Identification of those natural products and their biosynthesis will possibly reveal new virulence pathways that can be targeted to combat Legionella infection. Ultimately, the overall workflow will be generalized to investigate other novel natural products or potential virulent factors from the human pathogen Legionella to fight the emerging infectious disease by expanding the pool of 1) new classes of cytotoxic drug candidates/virulent factors and 2) new inhibition targets from the biosynthetic pathway.