ULTRA-HIGH RESOLUTION STRUCTURES OF THE SRP GTPASE AND ITS HETERODIMERIC RECEPTO

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。该提案有两个目的：第一个是完成来自水热菌的SRP GTPase， Ffh的GDP和GMPPNP复合物的超高分辨率数据收集。这些结构与先前在SSRL收集的载脂蛋白晶体数据将形成超高分辨率下Ffh结构状态比较分析的基础。虽然是GTPase超家族的一员，但SRP GTPase表现出许多新的特性，我们的目标是在蛋白质结构水平上理解。此外，我们已经建立了gtp依赖的SRP GTPase Ffh与其受体FtsY（也是GTPase）的复合物结晶的初步条件。我们期望在不久的将来优化结晶条件，并要求数据收集时间，以便使用MAD确定这种结构。Ffh/FtsY NG复合物的结构尤其重要，因为它将揭示在srp介导的靶向中起核心作用的分子“握手”的结构基础。

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. This proposal has two aims: the first is completion of ultra-high resolution data collection from the GDP and GMPPNP complexes of the SRP GTPase, Ffh, from Thermus aquaticus. These structures, with data from crystals of the apo protein previously collected at SSRL, will form the basis for a comparitive analysis of the structural states of Ffh at ultra-high resolution. Although a member of the GTPase superfamily, the SRP GTPase exhibits a number of novel properties that we aim to understand at a protein structural level. In addition, we have estabished preliminary conditions for crystallization of the GTP-dependent complex of the SRP GTPase Ffh with its receptor FtsY, also a GTPase. We anticipate optimization of the crystallization conditions in the near future, and are requesting data collection time in order to determine this structure using MAD. The structure of the Ffh/FtsY NG complex is particularly significant, because it will reveal the structural basis for the molecular 'handshake' that plays a central role in SRP-mediated targeting.