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: 10610932
• 负责人: Justin Andrew North
• 金额: $ 15.6万
• 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 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10610932
• 关键词: 5' -deoxyadenosine; Address; Aerobic; Amino Acids; 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; Intestines; Island; Laboratories; Liver Cirrhosis; Lower Organism; Metabolic; Metabolic Pathway; Metabolism; Methionine; Methods; Mutagenesis; Organism; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Persons; Physiological; Polyamines; Prevalence; Process; Protein Methylation; Proteomics; Quantitative Reverse Transcriptase PCR; Radiolabeled; Reaction; Regulatory Element; Resolution; Role; S-Adenosylhomocysteine; S-Adenosylmethionine; Shunt Device; Siderophores; Site; Structural Genes; Sulfate; Sulfur; Testing; Therapeutic; Therapeutic Agents; Translating; Work; analog; cost; design; experimental study; feeding; fitness; genetic regulatory protein; homoserine lactone; in vivo; inhibitor; 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.

项目概要 生物可利用的硫对于甲硫氨酸 (Met) 及其衍生物 S-腺苷-L- 的合成至关重要 蛋氨酸（SAM）。 SAM 用于多种代谢目的，主要作为 DNA 的甲基供体 和蛋白质甲基化，作为自由基-SAM反应的5'-脱氧腺苷自由基供体，作为氨丙基供体 用于多胺合成并参与酰基高丝氨酸内酯群体感应分子的合成 细菌。这种代谢的结果是产生一种死胡同的含硫副产物 5'-甲硫腺苷 （MTA）成立。 MTA 是多胺合成的产物抑制剂，MTA 积累被认为是有毒的。 由于无机硫的同化需要消耗大量能量，并且许多生物体都遇到贫硫的情况 环境中，维持或挽救适当的细胞有机硫库至关重要。此外，扰乱 蛋氨酸补救途径 (MSP) 的功能或功能降低会产生许多与健康相关的后果 包括对癌细胞生长和肝硬化的影响；该途径的中间体也已被证明 影响细胞凋亡过程，而这些中间体的类似物是有前途的治疗剂。新 最近，我们实验室发现了 MTA 途径，DHAP-乙烯和甲硫醇分流 据描述，其基因似乎广泛存在，并且在几种致病物种中选择性地发现。 这些属的非致病性物种不包含这些基因。因此，假设分流 基因/酶对这些致病物种的代谢具有特殊意义。而且，同样 最近发现新的基因和酶参与自由基 SAM 反应以产生和代谢 5’-脱氧腺苷 (5dAdo)，一种结构类似于 MTA 的副产品，可回收利用 碳回收。因此，长期目标是确定其作用和生理意义。 硫和碳回收的 DHAP/MTA/5dAdo 途径，以及这些途径影响硫和碳的潜力 成功代谢肠外致病性大肠杆菌 (ExPEC)，包括尿路致病性 (UPEC) 在特定发病岛上含有这些基因的菌株。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解决硫/碳的进一步代谢步骤 通过使用放射性标记 (14C) 和 13C MTA 和 5dAdo 野生代谢物的全细胞喂养实验进行挽救 型和突变株。这些体内研究将辅以特定酶的体外分析。 第二个目标（目标 2）将涉及解决这些基因如何受到基因调控，这是基因调控的一个重要方面。 这些生物体中的硫/碳回收。该项目具体目标的解决具有相当大的健康性 相关性，因为 ExPEC/UPEC 菌株会导致重大健康问题并感染数百万人。这是可以想象的 识别和解决特定的硫/碳回收途径对于 发病机制/适应性将为设计特定目标来抑制这些生物体引起的感染开辟道路。