Mechanisms of Copper and Silver Resistance in Microbial Systems

微生物系统中铜和银的耐药机制

• 批准号: 8437503
• 负责人: MEGAN M MCEVOY
• 金额: $ 27.59万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8437503
• 关键词: Antibiotic Resistance; Bacteria; Bacterial Infections; Binding; Biochemical; Biocide; Biological Models; Cells; Complex; Copper; Development; Drug Metabolic Detoxication; Energy-Generating Resources; Environment; Escherichia coli; Event; Food; Future; Genes; Genetic Transcription; Gram-Negative Bacteria; Growth; Health; Hospitals; Human; Infection; Infection prevention; Knowledge; Lead; Membrane; Metals; Microbe; Molecular; Monitor; Organism; Pathway interactions; Periplasmic Proteins; Phosphotransferases; Physiological; Population; Prevalence; Property; Proteins; Protons; Public Health; Resistance; Sensory; Silver; Stress; Structure; Substrate Specificity; System; Techniques; Testing; Time; Toxic effect; Transport Process; Water; Work; base; drug development; microbial; microorganism; microorganism growth; novel; periplasm; preference; protein-histidine kinase; public health relevance; response; sensor; tool

DESCRIPTION (provided by applicant): Metals are in widespread use to inhibit the growth of microbial populations. In particular, silver is commonly used in hospital settings as an effective broad spectrum biocide that has low toxicity to humans. However, protein systems are in place which enhance survival of microbes under conditions of high metal concentrations and reduce the efficacy of metals as broad spectrum biocides. One of these systems, the Cus system of E. coli, is responsible for sensing and responding to elevated levels of silver(I) and copper(I) in th environment. Despite its public health importance, the mechanisms of copper and silver handling by the Cus system are not well understood. We propose that mechanistic understandings of copper and silver handling will provide a target for future development of drugs and aid in understanding the limitations of metal-based biocides. In our previous work, we have focused on using the Cus system as a model system for a large class of microbial metal resistance systems. We have biochemically and structurally characterized two of the components, CusF and CusB, of the membrane spanning metal efflux system (CusCFBA) that actively removes metals from the cell. Additionally we have developed a novel and powerful technique to monitor metal transfer between proteins. The natural development of this previous work is to integrate these findings with the other proteins in the system. In aim 1 we will investigate the mechanism of metal transport by the Cus system and test the hypothesis that the Cus system is primarily important for detoxification of the periplasm, through metal transfer from the Cus periplasmic proteins (CusB and CusF) to the membrane-bound Cus proteins (CusA and CusC). In aim 2, we will test the hypothesis that CusS is activated by metal binding to the periplasmic domain, leading to conformational changes that ultimately result in activation of Cu(I)/Ag(I) resistance systems.. At the conclusion of these studies, we will have a detailed understanding of the microbial counterattack to metal contaminated environments. We will have determined how a specific metal is discriminated from other metals by a sensory and response system, the mechanisms of the transport process, and the further detoxification strategy after transport has occurred. These studies will give us the tools to understand the microbial response to metal biocides and provide strategies for their effective use in controlling bacterial infections in human populations.

描述（由申请人提供）：金属广泛用于抑制微生物种群的生长。特别是，银通常在医院环境中用作对人类毒性较低的有效广谱杀菌剂。然而，蛋白质系统已经到位，可以在高金属浓度的条件下增强微生物的存活，并降低金属作为宽光谱杀菌剂的疗效。这些系统之一是大肠杆菌的CUS系统，负责在TH环境中感应和响应升高的银（I）和铜（I）。尽管公共健康的重要性，但CUS系统的铜和白银处理机制尚不清楚。我们建议对铜和白银处理的机械理解将为未来的药物开发提供一个目标，并有助于理解金属杀菌剂的局限性。在以前的工作中，我们专注于使用CUS系统作为大型微生物金属电阻系统的模型系统。我们在生化和结构上表征了跨膜金属外排系统（CUSCFBA）的两个成分，即CUSF和CUSB，它们积极地从细胞中取出金属。此外，我们开发了一种新颖而强大的技术来监测蛋白质之间的金属转移。这项先前工作的自然发展是将这些发现与系统中的其他蛋白质整合在一起。在AIM 1中，我们将通过CUS系统研究金属转运的机理，并测试CUS系统主要对于通过CUS阴性质蛋白（CUSB和CUSF）转移到膜结合的CUS蛋白（CUSA和CUSA）（CUSA和CUSC）的金属转移，即CUS系统主要对于对周期的排毒至关重要。在AIM 2中，我们将检验以下假设：金属与周围质域的结合激活了CUSS，从而导致构象变化，最终导致Cu（i）/Ag（i）电阻系统的激活。在这些研究的结论中，我们将对对金属污染环境的微生物反击有详细的理解。我们将确定如何通过感官和响应系统，运输过程的机制以及运输后的进一步的排毒策略来区分其他金属。这些研究将为我们提供了解金属杀菌剂的微生物反应的工具，并为其在控制人群中的细菌感染方面有效使用策略。