Transition Metal Homeostasis and Reactive Sulfur Species in Bacterial Pathogens

摘要 细菌传染病是威胁人类健康的全球性疾病，迫切需要开发新的 限制危及生命的病原体影响的抗菌剂。这些病原体包括主要致病原 医院感染的病原体，如鲍曼不动杆菌和金黄色葡萄球菌，以及一种主要的 呼吸道病原体肺炎链球菌。在此续期申请中，我们寻求延续我们的 位于无机化学交叉点的创新、高度集成和专题研究计划 和微生物生理学，旨在解决我们在细菌过渡金属知识方面的重大空白 稳态(金属沉积)和硫化氢稳态。我的团队长期在 转录抑制蛋白(金属传感器)和金属配位体，使细菌对 限制过渡金属可获得性或导致金属毒性的努力。我们随后发现的 “感应”下游更多氧化形式的硫化氢的转录调控因子，统称为 活性硫物种(RSS)是我们理解通过蛋白质传递硫化氢信号的基础 过硫化(S-硫化)。事实上，一个新出现的共识认为，硫化氢的生物形成和 RSS提供对宿主武器活性氧和活性氮物种以及抗生素的保护， 在那里它们作为抗氧化剂和信号分子发挥作用。未来的研究将从四个方面进行 领域：1)研究转录调控中的变构，在那里我们扩展了我们的综合物理 将金属传感器描述为动态锚定到RSS传感器的“变构无机开关”，使用 最新的甲基核磁共振弛豫实验和基于质谱学的动力学 用于阐明RSS在不同结构类别中的特异性的广泛原则的剖析方法 2)对鲍曼不动杆菌的RSS信号假说进行了批判性的评估，该假说认为过硫化作用是 一种完全未在细菌中发现的调节性修饰；3)推断宿主过渡金属的全球影响 使用互补蛋白质组和金属蛋白质组工作流程的(锌、铁)饥饿(营养免疫) 在确定鲍曼不动杆菌金属蛋白靶标的同时，确定金属蛋白质组的变化；以及4) 阐明了一种鲜为人知的、与感染相关的儿茶酚铁获取和解毒途径。 肺炎。我们的多学科方法，无缝跨越生物物理、生物无机和分析 从化学到微生物生理学，将改变我们对病原体基本原理的理解 金属沉积和硫化氢/RSS生物发生，努力发现和表征新的参与者和 可以被新的抗菌策略作为目标的生物过程。

ABSTRACT Bacterial infectious disease is a global threat to human health and there is an urgent need to develop new antimicrobials that limit the impact of life-threatening pathogens. These pathogens include the major causative agents of nosocomial infections, e.g., Acinetobacter baumannii and Staphylococcus aureus, and a major respiratory pathogen, Streptococcus pneumoniae. In this renewal application, we seek continuation of our innovative, strongly integrated and topical research program positioned at an intersection of inorganic chemistry and microbial physiology, designed to tackle significant gaps in our knowledge in bacterial transition metal homeostasis (metallostasis) and hydrogen sulfide homeostasis. My group has long-standing interests in the transcriptional repressor proteins (metallosensors) and metallochaperones that allow a bacterium to respond to host efforts to restrict transition metal availability or induce metal toxicity. Our subsequent discovery of transcriptional regulators that “sense” downstream more oxidized forms of hydrogen sulfide, collectively termed reactive sulfur species (RSS), is foundational to our understanding of hydrogen sulfide signaling via protein persulfidation (S-sulfuration). Indeed, an emerging consensus holds that the biogenesis of hydrogen sulfide and RSS provides protection against host weapons reactive oxygen and reactive nitrogen species, and antibiotics, where they function as antioxidants and signaling molecules. Future research will be carried out in four general areas: 1) Investigating allostery in transcriptional regulation, where we extend our comprehensive physical description of metallosensors as dynamically-anchored “allosteric inorganic switches” to RSS sensors, using state-of-the-art methyl-specific NMR relaxation experiments and a novel mass spectrometry-based kinetic profiling method used to elucidate the broad principles of RSS specificity in diverse structural classes of regulators; 2) critically evaluate the RSS signaling hypothesis in A. baumannii, which posits that persulfidation is a regulatory modification, completely unexplored in bacteria; 3) deduce the global impact of host transition metal (zinc, iron) starvation (nutritional immunity) using complementary proteomics and metalloproteomics workflows to define changes in the metalloproteome while identifying metallochaperone targets, in A. baumannii; and 4) elucidate a poorly understood, infection-relevant iron-catecholate acquisition and detoxification pathway in S. pneumoniae. Our multidisciplinary approach, which seamlessly spans biophysical, bioinorganic and analytical chemistries to microbial physiology, will transform our understanding of foundational principles of pathogen metallostasis and hydrogen sulfide/RSS biogenesis in an effort to discover and characterize new players and biological processes that can be targeted by novel antibacterial strategies.