Characterization of pneumococcal secretion chaperones required for virulence

肺炎球菌毒力所需的分泌分子伴侣的特征 肺炎链球菌是一种革兰氏阳性病原体，通过空气飞沫传播， 定植于人鼻咽部，其中无症状携带是侵袭性疾病的先决条件。S. 肺炎是一种严重的健康威胁，在全球范围内造成的死亡人数超过任何其他传染病。在 为了S。当肺炎杆菌定植并转变为侵袭性感染时，细菌依赖于细菌的生长。 许多毒力因子的加工，这些毒力因子穿过细菌膜移位，并注定 附着在细胞壁上或分泌到宿主体内。尽管分泌的蛋白质在细胞中具有关键的重要性， 细菌的发病机制，很少有人知道的机制，调节蛋白质的活动， 革兰氏阳性菌的膜移位。我们的实验室鉴定了分泌伴侣PrsA 2 在革兰氏阳性细菌单核细胞增生李斯特菌（Lm），这是必不可少的毒力，并出现 是许多毒力因子正确折叠和分泌所必需的。我的研究 重点关注Lm的两个prsA等位基因：prsA 1和prsA 2，它们都具有肽基脯氨酰异构酶（PPIase） 除了折叠酶结构域之外，我们解决了Lm PrsA 1的晶体结构， PrsA 1和PrsA 2的结构特征有助于生物体中的PPI酶和伴侣活性。我 还确定了一些PrsA活性在物种之间广泛保守，而另一些则是 非常具体。我们最近解决了S的晶体结构。我和PrsA将使用这个结构 为了实现我的一些研究目标，以确定管理分泌的活动的机制， S.肺炎。中央到S。肺炎蛋白分泌的表面暴露 蛋白质：PrsA分子伴侣、HtrA蛋白酶/分子伴侣和SlrA PPIase。我假设在接待期间 感染，S. PrsA、HtrA和SlrA调节分泌的蛋白质的正确折叠、稳定和活性。 有助于定植和发病的蛋白质。此外，表面暴露的PrsA、HtrA和 SlrA是潜在的有吸引力的药物靶标，因为抑制可以增加抗生素敏感性， 减少毒力因子分泌。为了在K99辅导阶段实现我的研究目标，我 我将与我的导师Nancy Freitag博士密切合作，他是革兰氏阳性菌领域的专家 发病机制和我的合作者唐莫里森博士，谁是在该领域的专家在S。肺炎 分子遗传学和生物学。通过利用蛋白质组学分析技术的进步， 这个奖项将使我能够建立一个研究计划，长期目标是破译 革兰氏阳性菌S.肺炎 其也可能与其它重要的革兰氏阳性病原体具有广泛的相关性。

Characterization of pneumococcal secretion chaperones required for virulence Streptococcus pneumoniae is a Gram-positive pathogen that spreads through airborne droplets and colonizes the human nasopharynx where asymptomatic carriage is a prerequisite for invasive disease. S. pneumoniae is a significant health threat, globally causing more deaths than any other infectious disease. In order for S. pneumoniae to colonize and transition into an invasive infection, the bacterium relies on the elaboration of many virulence factors that are translocated across the bacterial membrane and destined for attachment to the cell wall or secretion into the host. Despite the pivotal importance of secreted proteins in bacterial pathogenesis, little is known about the mechanisms that regulate protein activity following membrane translocation in Gram-positive bacteria. Our laboratory identified the secretion chaperone PrsA2 in the Gram-positive bacterium Listeria monocytogenes (Lm) which is essential for virulence, and appears to be required for the proper folding and secretion of a number of virulence factors. My research has focused on the two prsA alleles of Lm: prsA1 and prsA2 that both have peptidyl-prolyl isomerase (PPIase) domains in addition to a foldase domain. We solved the crystal structure of Lm PrsA1 and I deciphered how structural features of PrsA1 and PrsA2 contribute to PPIase and chaperone activities in the organism. I have also determined that some PrsA activities are broadly conserved between species while others are highly specific. We recently solved the crystal structure of S. pneumoniae PrsA and I will use this structure to accomplish some of my research objectives to define the mechanisms that govern activity of secreted virulence factors in S. pneumoniae. Central to S. pneumoniae protein secretion are the surface exposed proteins: PrsA chaperone, HtrA protease/chaperone, and SlrA PPIase. I hypothesize that during host infection, S. pneumoniae PrsA, HtrA, and SlrA regulate proper folding, stabilization, and activity of secreted proteins which contribute to colonization and pathogenesis. In addition, surface exposed PrsA, HtrA and SlrA are potentially attractive drug targets because inhibition may increase antibiotic susceptibility while reducing virulence factor secretion. To implement my research objectives during the mentored K99 phase, I will work closely with my mentor Dr. Nancy Freitag who is an expert in the field of Gram-positive pathogenesis and my collaborator Dr. Don Morrison who is an expert in the field of S. pneumoniae molecular genetics and biology. By taking advantage of advances in proteomic analytical techniques, this award will enable me to establish a research program with the long-term objective of deciphering the mechanisms of virulence factor secretion and regulation in the Gram-positive pathogen S. pneumoniae which will also likely have broad relevance to other important Gram-positive pathogens.