SAXS STUDY ON THE CYTOPLASMIC CUBCOMPLEX FROM THE VIBRIO CHOLERAE TYPE 2 SECRETI

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。 霍乱弧菌等致病细菌使用II型分泌系统通过外膜输出其感染剂，如霍乱毒素。当孔位于外膜时，该系统由细胞质分泌ATPase(EPSE)提供能量。EPSE通过双功能内膜蛋白EPSL与系统的其余部分相连。来自相关系统的各种报道，如III型分泌物、IV型菌毛，表明核苷酸结合对EPSE的寡聚态有显著影响，并且寡聚态对ATPase活性有影响。然而，有迹象表明，EPSE与EPSL胞浆结构域的复合体(Cyto-EPSL)的寡聚模式与目前的学说不同。我们有证据表明，在核苷酸存在的情况下，EPSE(E)和Cyto-EPSL(CL)至少形成E2cL2，很可能形成E6cL6的寡聚体。我们建议进行溶液X射线散射研究，以研究这些组装作为不同核苷酸、镁以及温度的函数，以补充我们正在进行的对该体系的结晶学研究。我们的目标是确定与生理相关的集合体形式，并为更高分辨率的研究找到稳定的溶液条件。

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. Pathogenic bacteria such as Vibrio cholerae employ Type II Secretion Systems for the export of their infections agent such as cholera toxin through the outer membrane. While the pore is located in the outer membrane, the system is energized by a cytoplasmic secretion ATPase (EpsE). EpsE is linked to the rest of the system via the bitopic inner membrane protein EpsL. Various reports from related systems, e.g. Type III Secretion, Type IV Pili, indicate that nucleotide binding has a dramatic effect on the oligomeric state of EpsE, and that the oligomeric state has an effect on the ATPase activity. However, there are indications that the oligomerization pattern of EpsE in complex with the cytoplasmic domain of EpsL (cyto-EpsL) differs from the current dogma. We have evidence that EpsE (E) and cyto-EpsL (cL) form oligomeric assemblies at minimum E2cL2, and likely E6cL6, in the presence of nucleotides. We propose to conduct solution x-ray scattering studies to investigate these assemblies as a function of different nucleotides, Mg as well as of temperature to complement our on-going crystallographic studies on this system. Our aim is to identify the physiologically relevant form of assemblies and find solution condition to stabilize it for higher resolution studies.