Salvage of the sulfur and carbon byproducts of S-adenosylmethionine metabolism in pathogenic bacteria

病原菌中S-腺苷甲硫氨酸代谢的硫和碳副产物的回收

• 批准号: 10163801
• 负责人: TINA M. HENKIN
• 金额: $ 39万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-13 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10163801
• 关键词: 5' -deoxyadenosine; Address; Aerobic; Amino Acid Sequence; Amino Acids; Anaerobic Bacteria; Assimilations; Bacteria; Biological Availability; Cancer Cell Growth; Carbon; Cells; Consumption; DNA Methylation; Environment; Enzymes; Ethylenes; Exposure to; Gene Expression; Genes; Goals; Growth; Health; Human; In Vitro; Infection; Island; Laboratories; Lead; Liver Cirrhosis; Lower Organism; Metabolic; Metabolic Pathway; Metabolism; Methionine; Methods; Mutagenesis; Organism; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Physiological; Polyamines; Prevalence; Process; Protein Methylation; Proteomics; Radiolabeled; Reaction; Regulatory Element; Resolution; Reverse Transcriptase Polymerase Chain Reaction; Role; S-Adenosylmethionine; Shunt Device; Siderophores; Site; Structural Genes; Structure; Sulfate; Sulfur; Testing; Therapeutic; Therapeutic Agents; Translating; Uropathogenic E. coli; Work; analog; base; cost; design; experimental study; feeding; fitness; genetic regulatory protein; homoserine lactone; in vivo; inhibitor/antagonist; interest; mutant; novel; pathogen; pathogenic Escherichia coli; pathogenic bacteria; quorum sensing; shunt pathway; transcriptomics

Project Summary Biologically available sulfur is essential for the synthesis of methionine (Met) and its derivative, S-adenosyl-L- methionine (SAM). SAM is used for diverse metabolic purposes, serving primarily as a methyl donor for DNA and protein methylation, as a 5’-deoxyadenosyl radical donor for radical-SAM reactions, as an aminopropyl donor for polyamine synthesis and volved in the synthesis of acyl-homoserine lactone quorum sensing molecules in bacteria. As a consequence of this metabolism, a dead-end, sulfur-containing byproduct, 5’-methylthioadenosine (MTA) is formed. MTA is a product inhibitor of polyamine synthesis and MTA accumulation is thought to be toxic. Since the assimilation of inorganic sulfur is energetically costly and many organisms encounter sulfur-poor environments, maintaining or salvaging appropriate cellular organic sulfur pools is critical. Moreover, disruption or reduced functioning of methionine salvage pathways (MSPs) has many health-related consequences including influences on cancer cell growth and liver cirrhosis; intermediates of the pathway have also been shown to influence apoptopic processes, while analogs of these intermediates are promising therapeutic agents. Newly discovered MTA pathways from our laboratory, the DHAP-ethylene and methanethiol shunts, were recently described, the genes of which appear to be widespread and selectively found among several pathogenic species. Nonpathogenic species from these genera do not contain these genes. Thus, the hypothesis is that the shunt genes/enzymes hold some special significance to metabolism of these pathogenic species. Moreover, the same novel genes and enzymes were recently found to participate in radical SAM reactions to generate and metabolize 5’-deoxyadenosine (5dAdo), a structurally similar byproduct to MTA, which could potentially be recycled for carbon salvage. The long-term goal will thus be to determine the role and physiological significance of the DHAP/MTA/5dAdo pathways for sulfur and carbon salvage, and the potential of these pathways to influence the successful metabolism of extraintestinal pathogenic Escherichia coli (ExPEC), including uropathogenic (UPEC) strains which contain these genes on a specific pathogenesis island. A specific aim (Aim 1) will be to determine the precise role of these genes and encoded enzymes and resolve further metabolic steps in sulfur/carbon salvage via whole cell feeding experiments using radio-labeled (14C) and 13C MTA and 5dAdo metabolites in wild type and mutant strains. These in vivo studies will be supplemented by in vitro analyses with specific enzymes. The second aim (Aim 2) will involve resolving how these genes are genetically regulated, an important facet of sulfur/carbon salvage in these organisms. Resolution of the specific aims of this project have considerable health relevance as ExPEC/UPEC strains cause major health problems and infect millions of people. It is conceivable that the identification and resolution of a specific sulfur/carbon salvage pathway essential for pathogenesis/fitness will open the way to design specific targets to inhibit infections caused by these organisms.

项目摘要 生物学上可用的硫对于甲基氨酸（Met）及其衍生物S-腺苷-l-的合成至关重要 甲基氨酸（SAM）。 SAM用于潜水代谢目的，用作DNA的甲基供体 和蛋白甲基化，作为对自由基SAM反应的5'-脱氧丁选择自由基供体，作为氨基丙基供体 用于多胺合成，并在合成酰基 - 双层内酯的合成中 由于这种新陈代谢，含硫的副产品，5'-甲基硫代腺苷 （MTA）形成。 MTA是多胺合成的产物抑制剂，MTA积累被认为是有毒的。 由于无机硫的同化本质上是昂贵的，而且许多生物会遇到硫磺 环境，维持或挽救适当的细胞有机硫池至关重要。而且，破坏 或减少蛋氨酸拯救途径（MSP）的功能有许多与健康有关的后果 包括对癌细胞生长和肝硬化的影响；该路径的中间体也已显示 为了影响凋亡过程，而这些中间体的类似物是有希望的治疗剂。新 最近从我们实验室发现的MTA途径，DHAP-乙烯和甲烷乙醇分流器是 描述的是，其基因似乎是宽度的，并且在几种致病物种中有选择地发现。 来自这些属的非致病物质不包含这些基因。那是分流的假设 基因/酶对这些致病物种的代谢具有特殊意义。而且，一样 最近发现新型基因和酶参与自由基Sam反应以产生和代谢 5'-脱氧多生氨酸（5dado），一种与MTA结构相似的副产品，有可能被回收为 碳打捞。因此，长期目标是确定 DHAP/MTA/5DADO途径用于硫和碳救援，这些途径的潜力影响了 成功的新代谢，包括尿道病（UPEC），包括 在特定的发病机理上包含这些基因的菌株。具体目标（目标1）将是确定 这些基因和编码酶的精确作用，并在硫/碳中解决进一步的代谢步骤 通过全细胞喂养实验进行打捞，使用野外的无线电标签（14C）和13C MTA和5DADO代谢物在野外进行打捞 类型和突变菌株。这些体内研究将通过特定酶进行体外分析来补充。 第二个目标（AIM 2）将涉及解决这些基因的基因调节方式，这是一个重要方面 这些生物中的硫/碳打捞。该项目的具体目的的解决方案已经考虑了健康 与Expec/UPEC菌株相关的是，会导致重大健康问题和感染数百万。这是可以想象的 特定的硫/碳打捞途径的识别和解决 发病机理/适应性将为设计特定靶标抑制这些生物引起的感染开辟道路。