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

基本信息

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
项目类别：
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

项目摘要

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武器库的重要组成部分侵入宿主、损害组织并抑制革兰氏阴性细菌的免疫反应。复杂的机器可以跨两个膜分泌蛋白质：内膜自 1979 年发现以来，I 型分泌系统（T1SS）已在 800 多个细菌基因组中被发现，并且其许多底物有助于病原体的毒力，例如尿路致病性大肠杆菌中的溶血素 HlyA，肠沙门氏菌中的粘附素 SiiE 和百日咳博德特氏菌中的腺苷酸环化酶 CyaA。 T1SS 将未折叠的底物从细胞质分泌到细胞外环境。三个组成部分： ATP 结合盒转运蛋白（ABC 转运蛋白）周质衔接蛋白位于内膜，孔蛋白位于外膜。经典的“交替访问”模型无法解释大蛋白质底物是如何存在的由 T1SS ABC 转运蛋白跨内膜转运。分子水平上的底物分泌机制仍然不清楚。研究利用单粒子冷冻电子显微镜 (cryoEM)、生物信息学、体内和体外测定来回答该领域的关键问题，包括结构基础底物识别、易位途径的性质、底物能量学易位以及 T1SS ABC 转运蛋白活性的调节。大幅增加有关 T1SS 机制的基础科学知识并为开发未来针对广泛疾病的治疗干预措施提供新的基础细菌感染。