Structure of Proteins Involved in Bacterial Pathogenesis

参与细菌发病机制的蛋白质结构

• 批准号: 7318191
• 负责人: SCOTT J. HULTGREN
• 金额: $ 33.8万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7318191
• 关键词: Adhesives; Antibiotic Resistance; Bacteria; Bacterial Adhesins; Binding; Binding Sites; Biochemistry; Biogenesis; Bladder; C-terminal; Carbohydrates; Cell surface; Cells; Class; Closure; Collaborations; Communicable Diseases; Complex; Depth; Dimensions; Distal; Electron Microscopy; Epithelial; Epithelial Cells; Escherichia coli; Event; Family; Fiber; Fimbriae Proteins; Funding; Gene Cluster; Generations; Genes; Genetic; Glycolipids; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Growth; Hemagglutinin; Host Defense; Imagery; Immunocompromised Host; Immunoglobulins; Individual; Infection; Investigation; Iron binding capacity measurement; Kidney; Knowledge; Libraries; Ligands; Link; Mediating; Membrane; Membrane Proteins; Meningitis; Microbial Biofilms; Modeling; Molecular; Molecular Chaperones; Molecular Genetics; Molecular Structure; Morphology; N-terminal; Nature; Neonatal; Operon; Organism; PapG adhesin; Pathogenesis; Pathway interactions; Phosphotransferases; Pilum; Play; Process; Proteins; Pseudomonas; Pseudomonas adhesin; Pseudomonas aeruginosa; Range; Regulation; Reporter; Role; Salmonella; Sequence Homology; Series; Shapes; Sialic Acids; Signal Pathway; Signal Transduction; Site; Specificity; Structure; Surface; System; Testing; Thick; Tissues; Tropism; Uropathogenic E. coli; Virulence; Virulence Factors; Work; X-Ray Crystallography; base; biological adaptation to stress; capsule; cystic fibrosis patients; design; extracellular; functional hypothalamic amenorrhea; inhibitor/antagonist; insight; interdisciplinary approach; interest; macromolecular assembly; member; microbial; monomer; pathogen; periplasm; polymerization; prevent; protein structure; receptor; receptor binding; retinal rods; sensor; small molecule

DESCRIPTION (provided by applicant): Many of the adhesins of Gram-negative bacteria are incorporated into heteropolymeric fibers assembled by the chaperone/usher pathway. These fibers range in morphology from composite pili assembled by members of the FGS (F1G1 short) subfamily of chaperones, to fibrous capsule-like structures assembled by the FGL (F1G1 long) subfamily of chaperones. Here we propose to build on our work on P and type 1 pili, which has provided a paradigm for the assembly of hundreds of virulence fibers in diverse Gram-negative organisms. Using biochemistry, genetics, electron microscopy and X-ray crystallography, we have defined the structure and mechanism of action of the periplasmic chaperones in significant detail. We have solved the structure of the PapD periplasmic chaperone in complex with the tip adaptor subunit, PapK, and with the major tip subunit, PapE. We have also solved the structure of the PapE subunit in complex with the N-terminal extension of PapK and the structure of the receptor binding domain of the PapG adhesin with and without its host carbohydrate ligand. Pilus chaperones are comprised of two immunoglobulin (Ig)-like domains. These structures showed that pilin subunits also have an Ig-like fold, but they are missing their seventh (G) strand, thus exposing the hydrophobic core. In a process we termed donor-strand complementation, the chaperone's G1 strand serves as the pilin's seventh strand, catalyzing the folding of the subunit and preventing non-productive subunit aggregation. At the usher, pilus assembly occurs by donor-strand exchange, in which the G1 strand of the chaperone is replaced by an N-terminal extension that is present on every subunit and exposed on incoming chaperone-subunit complexes. The pilus subunit then undergoes a topological transition that triggers the closure of its groove, cementing its neighbor's NTE as part of its own Ig fold. Thus, the final pilus structure is a series of Ig-like domains, each of which is formed from parts of two individual subunit monomers. Each subunit has distinct specificity for other interactive subunits and distinct roles in pilus assembly. We propose to expand our knowledge of the structures of the pilus adhesins and further study the structure of the subunits and assembly machinery of two such assembly systems: the prototypical FGS P pilus system of uropathogenic Escherichia coli and the Saf FGL system of Salmonella. In addition, we will perform structural studies on anti-chaperone compounds.

描述（由申请人提供）：许多革兰氏阴性细菌的粘附素被掺入由伴侣/引座途径组装的杂聚纤维中。这些纤维的形态范围从由 FGS（F1G1 短）伴侣蛋白亚家族成员组装的复合菌毛到由 FGL（F1G1 长）伴侣蛋白亚家族组装的纤维囊状结构。在这里，我们建议以我们对 P 和 1 型菌毛的工作为基础，该工作为不同革兰氏阴性生物体中数百种毒力纤维的组装提供了范例。利用生物化学、遗传学、电子显微镜和 X 射线晶体学，我们非常详细地定义了周质伴侣的结构和作用机制。我们已经解决了与尖端接头亚基 PapK 和主要尖端亚基 PapE 复合的 PapD 周质伴侣的结构。我们还解析了与 PapK N 端延伸复合的 PapE 亚基的结构，以及具有和不具有其宿主碳水化合物配体的 PapG 粘附素的受体结合域的结构。菌毛伴侣由两个免疫球蛋白 (Ig) 样结构域组成。这些结构表明菌毛蛋白亚基也具有 Ig 样折叠，但它们缺少第七条 (G) 链，从而暴露了疏水核心。在我们称为供体链互补的过程中，伴侣的 G1 链充当菌毛蛋白的第七条链，催化亚基折叠并防止非生产性亚基聚集。在引座处，菌毛组装通过供体链交换进行，其中伴侣蛋白的 G1 链被每个亚基上存在的 N 端延伸取代，并暴露在传入的伴侣蛋白-亚基复合物上。然后，菌毛亚基经历拓扑转变，触发其凹槽的闭合，从而将其邻近的 NTE 巩固为自身 Ig 折叠的一部分。因此，最终的菌毛结构是一系列 Ig 样结构域，每个结构域均由两个单独的亚基单体的部分形成。每个亚基对其他相互作用的亚基具有独特的特异性，并且在菌毛组装中具有不同的作用。我们建议扩大我们对菌毛粘附素结构的了解，并进一步研究两个这样的组装系统的亚基结构和组装机制：尿路病原性大肠杆菌的原型 FGS P 菌毛系统和沙门氏菌的 Saf FGL 系统。此外，我们还将进行抗伴侣化合物的结构研究。