Molecular Mechanisms of the Type I Secretion System from Bacterial Pathogens

细菌病原体I型分泌系统的分子机制

• 批准号: 10297142
• 负责人: Wei Mi
• 金额: $ 35.18万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10297142
• 关键词: ATP phosphohydrolase; ATP-Binding Cassette Transporters; Adaptor Signaling Protein; Adenylate Cyclase; Bacterial Genome; Bacterial Infections; Binding; Biochemical; Bioinformatics; Biological Assay; Bordetella pertussis; C-terminal; Cells; Childhood; Complex; Cryoelectron Microscopy; Cytoplasm; Data; Electron Spin Resonance Spectroscopy; Environment; Escherichia coli Adhesins; Exposure to; Future; Glycine; Goals; Gram-Negative Bacteria; Hemolysin; Hydrolysis; Immune response; In Vitro; Interdisciplinary Study; Invaded; Ion Channel; Kingella kingae; Knowledge; Location; Membrane; Modeling; Molecular; Molecular Conformation; Movement; Mutation; Names; Nature; Nucleotides; Pathway interactions; Pertussis; Play; Protein Secretion; Proteins; Reaction; Regulation; Research; Resolution; Role; Salmonella enterica; Signal Transduction; Site; Structural Models; Structure; System; Therapeutic Intervention; Tissues; Toxin; Transmembrane Domain; Uropathogenic E. coli; VDAC1 gene; Virulence; base; design; extracellular; improved; in vitro Assay; in vivo; inhibitor/antagonist; particle; pathogen; pathogenic bacteria; periplasm; polypeptide; prevent; screening; small molecule

ABSTRACT Protein secretion is an essential component of the arsenal used by many bacterial pathogens to invade hosts, damage tissues, and suppress immune responses. Gram-negative bacteria have evolved sophisticated machines to secrete proteins across two membranes: the inner membrane and outer membrane. Since discovered in 1979, the type I secretion system (T1SS) has been identified in more than 800 bacterial genomes, and many of its substrates contribute to the virulence of pathogens, examples being hemolysin HlyA in uropathogenic Escherichia coli, adhesin SiiE in Salmonella enterica, and adenylate cyclase CyaA in Bordetella pertussis. The T1SS secretes unfolded substrates from the cytoplasm to the extracellular milieu. It includes three components: an ATP-binding cassette transporter (ABC transporter), associated periplasmic adapter proteins located in the inner membrane, and a porin in the outer membrane. The canonical “alternating access” model cannot explain how the large protein substrates are transported by the T1SS ABC transporter across the inner membrane. Therefore, the mechanisms of substrate secretion at the molecular level is still obscure. The proposed research leverages single particle cryo-electron microscopy (cryoEM), bioinformatics, in vivo and in vitro assays to answer key questions in the field, including the structural basis of substrate recognition, the nature of the translocation pathway, the energetics for substrate translocation, and the regulation of the T1SS ABC transporter's activity. The studies will substantially increase the fundamental scientific knowledge about the mechanisms of the T1SS and provide a new basis for developing future therapeutic interventions against a broad range of bacterial infections.

抽象的 蛋白质分泌是许多细菌病原体使用的阿森纳的重要组成部分 入侵宿主，损害组织和抑制免疫反应。革兰氏阴性细菌具有 将复杂的机器进化为跨两个膜的秘密蛋白质：内部 膜和外膜。自1979年发现以来，I型分泌系统（T1SS） 已经在800多个细菌基因组中鉴定出来，其许多底物有助于 对于病原体的病毒，例如尿道疾病大肠杆菌中的hlya hlya的例子， 沙门氏菌中的粘合素siie，以及百日草的Bordetella cyaa。 T1SS的秘密从细胞质到细胞外环境展开了底物。它包括 三个组件：ATP结合盒转运蛋白（ABC转运蛋白），相关 周内膜中的周质适配器蛋白和外膜中的孔蛋白。 规范的“交替访问”模型无法解释大蛋白底物的方式 由T1SS ABC转运蛋白运输于内膜。因此， 分子水平的底物分泌的机理仍然晦涩。提议 研究利用单粒子冷冻电子显微镜（冷冻），生物信息学，体内 并在体外测定法回答现场的关键问题，包括 底物识别，易位途径的性质，底物的能量学 易位，以及T1SS ABC转运蛋白活性的调节。研究会 大大提高了有关T1S机制的基本科学知识 并为开发未来的治疗干预措施提供了新的基础 细菌感染。