Copper transport in Mycobacterium tuberculosis

结核分枝杆菌中的铜转运

基本信息

批准号：
8287161
负责人：
MICHAEL NIEDERWEIS
金额：
$ 35.9万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-13 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8287161
关键词：
Bacteria Biological Process Carrier Proteins Cause of Death Copper Cysteine Defect Drug Efflux Drug Metabolic Detoxication Environment Escherichia coli Genus Mycobacterium Growth Homeostasis In Vitro Interferons Ion Channel Label Libraries Mass Spectrum Analysis Medical Membrane Membrane Lipids Membrane Proteins Metals Micronutrients Molecular Mus Mycobacterium tuberculosis Oxidation-Reduction Pathogenesis Permeability Phagosomes Pharmaceutical Preparations Predisposition Process Proteins Pump Role Screening procedure Structure Substrate Specificity Surface Surface Plasmon Resonance System Transport Process Virulence X-Ray Crystallography bactericide copper oxidase crosslink efflux pump fascinate in vivo interest light scattering macrophage mutant novel pathogen porin protein crosslink research study resistance mechanism solute uptake wasting

项目摘要

A crucial component in the ability of Mtb to survive in bactericidal environments such as the phagosome of macrophages is the efficient permeability barrier established by its unusual outer membrane (OM). We have discovered that an Mtb mutant lacking the OM channel protein Rv1698 was more susceptible to copper. Copper is an essential micronutrient, but excess copper is toxic. The intracellular copper concentration of the rv1698 mutant was 100-fold increased. Our experiments demonstrated that Rv1698 is required for copper efflux across the OM and for maintaining low intracellular copper levels. Because efflux against a concentration gradient requires energy, the OM component of efflux systems in E. coli is connected to an inner membrane pump which contributes substrate specificity and energy to the transport process. However, it is unknown how Mtb extrudes waste molecules, drugs, and other toxic solutes. Rv1698 is the first OM component of any efflux system in mycobacteria and, hence, represents a great opportunity not only to examine how Mtb controls essential, but toxic redox-active metals such as copper, but also efflux processes in Mtb in general. Copper inside Mtb-containing phagosomes is increased upon stimulation of macrophages with interferon-¿ to concentrations that are sufficient to inhibit growth of Mtb indicating that copper homeostasis is critical for virulence of Mtb. However, this is a largely unexplored field for Mtb. We, therefore, propose to characterize the novel copper efflux channel MctB and interacting proteins, to identify missing components of copper homeostasis and to assess their role in virulence of Mtb.

结核分枝杆菌在杀菌环境（如噬菌体的吞噬体）中生存能力的关键组成部分巨噬细胞是由其不寻常的外膜（OM）建立的有效渗透屏障。发现缺乏 OM 通道蛋白 Rv1698 的 Mtb 突变体对铜更敏感。铜是一种必需的微量营养素，但过量的铜是有毒的。 rv1698 突变体增加了 100 倍。我们的实验表明，Rv1698 是铜所必需的。穿过 OM 的外排并维持较低的细胞内铜水平。浓度梯度需要能量，大肠杆菌外排系统的 OM 组件与内部膜泵为运输过程提供底物特异性和能量。未知 Mtb 如何排出废物分子、药物和其他有毒溶质 Rv1698 是第一个 OM。分枝杆菌中任何外排系统的组成部分，因此，代表着一个巨大的机会，不仅研究 Mtb 如何控制重要但有毒的氧化还原活性金属（例如铜）以及外排过程山地车一般。用干扰素-¿刺激巨噬细胞后，含 Mtb 的吞噬体内的铜含量会增加到足以抑制 Mtb 生长的浓度，表明铜稳态对于 Mtb 至关重要然而，对于 Mtb 来说，这在很大程度上是一个尚未探索的领域。新型铜流出通道 MctB 与蛋白质相互作用，以识别铜的缺失成分体内平衡并评估其在 Mtb 毒力中的作用。