Biogenesis of Bordetella cell envelope components

革兰氏阴性菌的包膜是复杂的。它由内膜和细胞壁组成。细胞壁由一个由磷脂和脂多糖组成的不对称外膜双层包围着一个薄的肽聚糖结构，膜内附着或嵌入了各种(Lipoo)蛋白。内膜和外膜之间的间隙称为周质。除了起到选择性屏障的作用，保护细菌免受恶劣条件的影响外，外膜还在决定细菌与环境之间相互作用的结果方面发挥着关键作用。事实上，细胞膜的几个成分是受环境条件调节的。此外，包膜成分的生物发生也很复杂；将包膜成分定位于特定位置需要专用的分子机制和机制，以保持组件处于适合穿越一个或多个膜的状态。这些机制还可帮助促进成分到达目的地后的功能。*本提案涉及构成波氏杆菌属包膜的成分。许多波尔德氏菌物种是人类或动物的病原体，关于波尔德氏菌包膜是如何制成的，有很多需要了解的东西。我们将专注于波尔德氏菌包膜的两个方面--称为自体转运蛋白的表面蛋白的生物发生和修改脂类A部分脂多糖的系统。我们将描述两个具有不同和非典型结构的新型自体转运蛋白是如何分泌通过外膜的。我们将确定对辅助因子的需求，这些自转运蛋白如何与辅助因子相互作用，自转运蛋白C末端在影响分泌中的作用，以及蛋白质在分泌后如何在细菌表面折叠。关于脂类A的修饰，我们将描述一组蛋白质如何共同作用于细胞膜内膜上的氨基葡萄糖修饰类脂A的机制。这一过程受到高度调控，预计将涉及几个调控系统，包括假定的反义RNA。我们将研究这一系统是如何协调的。*了解膜是如何构建的，特别是在非模式生物中，可以揭示膜和膜蛋白和脂类如何形成的基本原理，还可以改进细胞表面展示或操纵的方法，用于生物和纳米技术应用。*

The envelope of Gram negative bacteria is complex. It comprises the inner membrane and the cell wall. The cell wall consists of a thin peptidoglycan structure surrounded by an asymmetric outer membrane bilayer consisting of phospholipids and lipopolysaccharides within which are attached or embedded various (lipo)proteins. The space between the inner and outer membranes is called the periplasm. In addition to functioning as a selective barrier and protecting bacteria from harsh conditions, the envelope plays a critical role in determining the outcome of interactions between the bacterium and its environment. Indeed, several components of the cell envelope are regulated in response to environmental conditions. Furthermore, the biogenesis of envelope components is also complex; targeting envelope components to specific locations requires dedicated molecular machinery and mechanisms that maintain the components in a state suited to being able to traverse one or more membranes. These mechanisms may also assist in promoting the function of the components once they have reached their destination.***This proposal addresses components comprising the envelope of Bordetella species. Many Bordetella species are human or animal pathogens and there is much to learn about how the Bordetella envelope is made. We will focus on two aspects of the Bordetella envelope – the biogenesis of surface proteins called autotransporters and a system that modifies the lipid A portion of lipopolysaccharide. We will characterize how two novel autotransporters with distinct and non-typical structures are secreted past the outer membrane. We will ascertain the requirement for accessory factors, how these autotransporter proteins interact with accessory factors, the role of the autotransporter C-terminus in effecting secretion, and how the proteins fold on the bacterial surface following secretion. With respect to lipid A modification, we will characterize the mechanism of how a group of proteins function together to modify lipid A with glucosamine at the inner membrane of the cell envelope. This process is highly regulated and is predicted to involve several regulatory systems, including a putative anti-sense RNA. We will investigate how this system is coordinated.****Understanding how the envelope is built, especially in non model organisms can lead to uncovering fundamental principles of how membranes and membrane proteins and lipids are made and can also lead to improved methods for cell surface display or manipulation that can be used in bio and nanotechnology applications.***