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.

项目摘要 生物有效硫是合成蛋氨酸(Met)及其衍生物S-腺苷-L所必需的. 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‘-脱氧腺苷供体，作为氨丙基供体 多胺的合成和酰基高丝氨酸内酯群体感应分子的合成 细菌。作为这种新陈代谢的结果，一种死胡同的含硫副产品5‘-甲硫腺苷 (MTA)成立。MTA是多胺合成的产物抑制剂，MTA的积累被认为是有毒的。 由于无机硫的同化耗费能源，而且许多生物都面临缺硫的问题。 在环境条件允许的情况下，维护或抢救适当的蜂窝状有机硫库至关重要。此外，颠覆 蛋氨酸挽救途径(MSP)的功能降低会导致许多与健康相关的后果 包括对癌细胞生长和肝硬变的影响；也显示了该途径的中间产物 影响细胞凋亡过程，而这些中间体的类似物是很有前途的治疗剂。新开 从我们实验室发现的MTA通路，DHAP-乙烯和甲硫醇分流，是最近 其基因似乎在几个致病物种中广泛存在并有选择性地被发现。 这些属的非致病物种不包含这些基因。因此，假设是分流 基因/酶对这些病原菌的代谢具有特殊的意义。此外，同样的 最近发现新的基因和酶参与自由基SAM反应产生和代谢 5‘-脱氧腺苷(5dAdo)，一种与MTA结构相似的副产品，可能被回收用于 碳回收。因此，长期的目标将是确定细胞的作用和生理意义 DHAP/MTA/5dADO硫和碳挽救途径，以及这些途径影响 肠外致病性大肠杆菌(ExPEC)，包括尿路致病性(UPEC)的成功代谢 在特定致病岛上含有这些基因的菌株。一个具体的目标(目标1)是确定 这些基因和编码酶的确切作用，并解决硫/碳的进一步代谢步骤 放射性标记(~(14)C)和~(13)C MTA和~(13)C-5dADO代谢产物在野外全细胞饲养实验中的抢救 模式菌株和突变菌株。这些体内研究将得到特定酶的体外分析的补充。 第二个目标(目标2)将涉及解决这些基因是如何受到基因调控的，这是 硫/碳在这些生物体中的挽救。这个项目的具体目标的解决有相当大的健康 由于ExPEC/UPEC菌株导致重大健康问题并感染数百万人，因此具有相关性。这是可以想象的 识别和解析特定的硫/碳挽救途径对于 致病机理/适合性将为设计特定的靶点以抑制由这些微生物引起的感染开辟道路。