Direct gas sensing and repellent response to toxic gases in anaerobic pathogens

对厌氧病原体中有毒气体的直接气体传感和驱避反应

• 批准号: 8617093
• 负责人: Charles W Hespen
• 金额: $ 3.62万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-16 至 2016-02-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8617093
• 关键词: Aerobic Bacteria; Affect; Affinity; Anaerobic Bacteria; Antibiotics; Bacteria; Binding; Binding Proteins; Biology; Botulism; Chemicals; Chemotaxis; Clostridium; Clostridium botulinum; Clostridium tetani; Deuterium; Escherichia coli; Gases; Genomics; Heme; Homologous Gene; Hydrogen; Investigation; Knowledge; Ligand Binding; Ligands; Locomotion; Mammals; Maps; Mass Spectrum Analysis; Molecular; Nitric Oxide; Organism; Output; Oxygen; Panic; Pathway interactions; Proteins; Relative (related person); Research; Signal Pathway; Signal Transduction; Stimulus; Swimming; Tertiary Protein Structure; Tetanus; Thermoanaerobacter; Work; bacterial resistance; botulinum; design; foodborne pathogen; hazard; in vivo; methyl-accepting chemotaxis proteins; mutant; novel; pathogen; public health relevance; research study; response; sensor; stem; transmission process

DESCRIPTION (provided by applicant): Bacterial pathogens possess elaborate mechanisms to sense and avoid chemical hazards. One important mechanism in environmental sensing is chemotaxis, a two-component signaling pathway responsible for directional change in bacterial swimming. Recently, methyl-accepting chemotaxis proteins (MCP) fused to Heme Nitric oxide/Oxygen (H-NOX) sensor domains were identified through genomic analyses of the obligate anaerobic pathogens Clostridium botulinum and Clostridium tetani. Ubiquitous in biology, H-NOX domains are found in organisms from bacteria to mammals. A molecular understanding of ligand binding has been established. However, the signal propagation mechanisms of these domains in obligate anaerobic bacteria are still unknown. Previously characterized gas-sensing chemotaxis proteins respond indirectly to gases. For example, Aer, the oxygen sensor in E. coli, senses changes in cytosolic reduction potential as oxygen concentration changes. The H-NOX-MCP may act as a heretofore-uncharacterized direct gas sensor in which the H-NOX domain binds small concentrations of ligand and induces a panic evasion response in bacteria. In this research plan, signal output and ligand sensitivity of the H NOX-MCP protein will be investigated in the presence of oxygen or nitric oxide. To understand the mechanism of signal transmission, the molecular interactions between H-NOX and MCP domains will also be studied. Finally, in vivo chemotaxis experiments will be performed on wild type and H-NOX-MCP mutants of Clostridium sporogenes, a close relative to C. botulinum, to understand how the organism responds to steadily increasing concentrations of oxygen and nitric oxide. This investigation will expand knowledge of bacterial two-component signaling as well as characterize a novel mechanism for toxic gas sensing common to pathogenic species of Clostridium.

描述（由申请人提供）：细菌病原体具有感知和避免化学危害的复杂机制。趋化性是环境感知的一个重要机制，是一种负责细菌游动方向变化的双组分信号通路。最近，甲基接受趋化蛋白（MCP）融合血红素一氧化氮/氧（H-NOX）传感器域被确定通过专性厌氧病原体肉毒梭菌和破伤风梭菌的基因组分析。H-NOX结构域在生物学中普遍存在，在从细菌到哺乳动物的生物体中发现。已经建立了对配体结合的分子理解。然而，这些结构域在专性厌氧菌中的信号传播机制仍然是未知的。先前表征的气敏趋化性蛋白间接响应气体。例如，Aer，E.大肠杆菌，传感器的变化，细胞溶质的还原电位作为氧浓度的变化。H-NOX-MCP可以充当迄今为止未表征的直接气体传感器，其中H-NOX结构域结合小浓度的配体并在细菌中诱导恐慌逃避反应。 在本研究计划中，H的信号输出和配体敏感性 将在氧或一氧化氮存在下研究NOX-MCP蛋白。为了理解信号传递的机制，还将研究H-NOX和MCP结构域之间的分子相互作用。最后，将对生孢梭菌的野生型和H-NOX-MCP突变体进行体内趋化性实验，生孢梭菌是C.肉毒杆菌，以了解有机体如何应对稳步增加浓度的氧气和一氧化氮。这项调查将扩大知识的细菌双组分信号，以及表征一种新的机制，常见的致病性梭菌属的有毒气体传感。