NMR AND COMPUTATIONAL STUDIES OF PROTEIN TRANSLOCATION IN BACTERIAL NEEDLES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 III型分泌系统(TTSS)是一种多蛋白质分子机器，被许多革兰氏阴性细菌用来对接到真核宿主细胞膜上，并输出效应蛋白以启动感染。它的装置由跨越细菌内外膜的基底、外部针头和尖端蛋白组成。针由大约120个拷贝的针单体围绕中心通道组装而成。然而，形成通道的针状单体的N-末端区域的结构由于其柔性的性质而没有被很好地定义。在这项提案中，我们将结合计算和实验方法来确定针状蛋白的N-末端区域的结构，改进针状模型，并表征蛋白质如何通过这一通道运输的结构基础。由于使用TTSS的细菌病原体因其引起的各种疾病和抗生素耐药性的产生而对公众健康和安全构成重大问题，全面了解TTSS中使用的效应器易位机制将有助于针对这些细菌引起的疾病的疫苗和药物开发。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The type III secretion system (TTSS) is a multi-protein molecular machine that is used by many Gram-negative bacteria to dock onto the eukaryotic host cell membrane and export effector proteins to initiate infections. Its apparatus is composed of a basal body that spans the inner and outer bacterial membranes, an external needle, and a tip protein. The needle is formed by the assembly of approximately 120 copies of needle monomers around a central channel. However, the structures of the N-terminal regions of needle monomers that form the channel are not well defined due to their flexible nature. In this proposal, we will combine computational and experimental approaches to determine the structure of the N-terminal regions of the needle proteins, refine the needle model, and characterize the structural basis of how proteins are transported across this channel. Since the bacterial pathogens that use the TTSS pose major problems in public health and safety due to the diverse diseases they cause and the development of antibiotic resistance, a comprehensive understanding of the effector translocation mechanism used in the TTSS will facilitate vaccine and drug developments against the diseases caused by these bacteria.