Mycoplasma – Structural Characterization of Host Cell Interaction Determinants

支原体 â 宿主细胞相互作用决定因素的结构表征

• 批准号: 274962763
• 负责人: Professor Dr. Achilleas Frangakis
• 金额: --
• 依托单位: Institut für Biophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/274962763?language=en
• 关键词: Mycoplasma; Structural; Characterization; Host; Cell

Mycoplasmas are among the smallest and simplest prokaryotes capable of self-replication, with a genome which may be as small as 600 kbases. They are significant pathogens that may induce clinically relevant manifestations. In the previous funding period we used cryo- electron microscopy to solve the structure of the main adhesion complex of Mycoplasma pneumoniae and Mycoplasma genitalium, the Nap, that is responsible for the adhesion of the pathogens to host cells and indispensable for manifesting the infection. In addition, we studied numerous mutants of M. genitalium by cryo-electron tomography, which allowed for explaining the mechanism of adhesion and motility. Here we apply for funding to continue this study using two avenues: (i) Using single-particle cryo-electron microscopy to solve the structure of the intracellular part of the Nap (Napic), for which we have evidence that it is responsible for triggering the adhesion release mechanism, and of further immunodominant and/or abundant Mycoplasma surface proteins (specifically P116/MG075 and MPN474/MG328). The structures will complement our previous structures of the main adhesin and should provide us with a complete mechanistic understanding of the adhesion. Mechanistic understanding of the adhesion has the potential for facilitating development of new therapeutics against these pathogens that are notoriously difficult to control with current antibiotics. (ii) Using cryo- electron tomography and a focused-ion-beam approach, we would like to investigate the direct interaction of the Mycoplasmas with host cells to understand how the infection manifests. In particular, we would also like to visualize the adhesion of Mycoplasmas to epithelial cilia, which apparently causes ciliary dysfunction during the infection. For both of the above avenues we have already done significant prior work, both independently and as members of a vibrant collaborative community. Finally, the motivation for our work is reinforced by recent studies that have reported a critical role of Mycoplasma pneumoniae for the clinical outcome of viral infections of the respiratory tract.

支原体是最小、最简单的能够自我复制的原核生物之一，其基因组可能小至 600 kbase。它们是可能诱发临床相关表现的重要病原体。在之前的资助期间，我们使用冷冻电子显微镜来解析肺炎支原体和生殖支原体的主要粘附复合物Nap的结构，该复合物负责病原体与宿主细胞的粘附，并且是表现感染所必需的。此外，我们通过冷冻电子断层扫描研究了生殖支原体的许多突变体，这可以解释粘附和运动的机制。在这里，我们申请资金以通过两种途径继续这项研究：（i）使用单颗粒冷冻电子显微镜来解析 Nap（Napic）的细胞内部分的结构，为此我们有证据表明它负责触发粘附释放机制，以及进一步的免疫显性和/或丰富的支原体表面蛋白（特别是 P116/MG075 和 MPN474/MG328）。这些结构将补充我们之前的主要粘附素结构，并为我们提供对粘附的完整机制理解。对粘附机制的理解有可能促进针对这些病原体的新疗法的开发，而众所周知，目前的抗生素很难控制这些病原体。 (ii) 使用冷冻电子断层扫描和聚焦离子束方法，我们希望研究支原体与宿主细胞的直接相互作用，以了解感染的表现。特别是，我们还想观察支原体对上皮纤毛的粘附，这显然会在感染过程中导致纤毛功能障碍。对于上述两种途径，我们已经独立地和作为充满活力的协作社区的成员完成了重要的前期工作。最后，最近的研究报告了肺炎支原体对呼吸道病毒感染的临床结果的关键作用，这增强了我们工作的动力。