Regulation and function of bacterial 100S ribosome

摘要 在细菌蛋白质合成过程中，30s和50s核糖体亚基在翻译上组装成 70年代核糖体在模板mRNA上的活性。革兰氏阳性人类致病菌中的葡萄球菌 金黄色，一种名为冬眠促进因子(HPFSa)的小核糖体结合蛋白刺激 2.5-丙二醛70秒单体的二聚化形成翻译沉默的100秒复合体。生理学 100S核糖体的功能仍然是个谜，因为100S核糖体的时间丰度 在不同的细菌门之间有很大的差异，100s核糖体对翻译的全球影响是 完全未知，不同细菌的Hpf零突变缺乏共同的表型。此外，在遥远的地方 相关的伽马蛋白细菌，如大肠杆菌，需要两种蛋白质(RMFEc和HPFEc)才能达到100s 复杂的队形。我们课题组的最新数据表明，HPFSa对细菌的生存是必不可少的 以及维持老化的金黄色葡萄球菌细胞中的核糖体池。令人惊讶的是，消除hpfSa会导致 在翻译起始时只去抑制一小部分基因。我们的目标是建立一种机械式的 了解100S核糖体在翻译能力和葡萄球菌发病机制中的作用。 我们将采取跨越遗传学、分子生物物理、生物化学和整体的多学科方法 动物感染研究。目标1将确定可逆转换过程和涉及的因素 70s和100s核糖体。目标2将确定HPFSa/100S核糖体如何抑制基因的翻译- 具体的方式。目标3将确定100S复合体在核糖体转换和葡萄球菌中的作用 病理生理学。这些目标有可能对核糖体新陈代谢和 启发对持续和复发的葡萄球菌感染的替代治疗，这些感染与 在宿主体内存活较长时间。

SUMMARY During bacterial protein synthesis, the 30S and 50S ribosomal subunits assemble into the translationally active 70S ribosome on template mRNA. In the Gram-positive human bacterial pathogen Staphylococcus aureus, a single small ribosome-binding protein called hibernation-promoting factor (HPFSa) stimulates the dimerization of 2.5-MDa 70S monomers to form the translationally silent 100S complex. The physiological function of the 100S ribosome remains enigmatic because the temporal abundance of the 100S ribosome varies considerably among different bacterial phyla, the global impact of the 100S ribosome on translation is completely unknown, and hpf null mutants of different bacteria lack a common phenotype. Moreover, distantly related gammaproteobacteria, such as E. coli, require two proteins (RMFEc and HPFEc) to achieve 100S complex formation. Recent data from our group demonstrate that HPFSa is essential for the bacterial survival and maintenance of the ribosome pool in aging S. aureus cells. Surprisingly, eliminating hpfSa causes the derepression of only a subset of genes at translational initiation. Our goal is to establish a mechanistic understanding of the function of the 100S ribosome in translational capacity and staphylococcal pathogenesis. We will take a multi-disciplinary approach that spans genetics, molecular biophysics, biochemistry, and whole animal infection studies. Aim 1 will determine the process and factors involved in the reversible conversion of 70S and 100S ribosomes. Aim 2 will determine how the HPFSa/100S ribosome inhibits translation in a gene- specific manner. Aim 3 will identify the roles of the 100S complex in ribosome turnover and staphylococcal pathophysiology. These aims have the potential to produce novel insights into ribosome metabolism and inspire alternate treatments for persistent and relapsed staphylococcal infections that are intimately linked to survive for an extended period inside the host.