STRUCTURAL STUDIES OF AAA ATPASES

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 蛋白质必须正确折叠以获得生物功能。同时，蛋白质聚集和错误折叠是许多破坏性人类疾病如阿尔茨海默病和朊病毒介导的感染的关键因素。与其他更常规的分子伴侣不同，酪蛋白分解蛋白酶B（Clp B）及其酵母同系物热休克蛋白104（Hsp 104）具有将蛋白质从先前聚集状态中拯救出来的显著能力。ClpB/Hsp 104家族的成员形成分子量约为600 kDa的六聚环结构，并转化来自ATP结合的化学能， 水解转化为机械功。本研究的目的是提供一个详细的机制，了解ClpB和Hsp 104如何促进先前聚集的蛋白质的解离。 项目1：ClpB六聚体的结构 ClpB是ATP依赖性分子机器，其形成600-kDa的六聚体环结构，并且属于Clp/Hsp 100家族的AAA+蛋白。然而，与其他分子伴侣不同，ClpB既不促进正向折叠也不阻止蛋白质的聚集。相反，ClpB具有从聚集状态中拯救应激损伤蛋白的显着能力;这是诱导耐热性所必需的功能。 虽然结构-功能关系开始被理解，但仍不清楚ClpB如何将来自ATP结合和水解的能量转化为机械功。 项目2：Hsp 104分子伴侣的结构 Hsp 104是一种ATP依赖性蛋白质重塑因子，它与ClpB一样，可以将应激损伤的蛋白质从先前的聚集状态中拯救出来。虽然这样做的能力与细菌ClpB共享，但潜在的机制不同。例如，已经提出Hsp 104的第二AAA结构域对于寡聚化是必需的，并且对于底物结合是必需的，而对于ClpB则相反。为了提供对Hsp 104的详细机制理解，我们使用cryoEM来确定Hsp 104在核苷酸结合和游离状态下的结构

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. Proteins must fold correctly in order to attain biological function. Concurrently, protein aggregation and misfolding are key contributors to many devastating human diseases such as Alzheimer's disease and prion-mediated infections. Unlike other more conventional molecular chaperones, the caseinolytic protease B (ClpB) and its yeast homolog heat-shock protein 104 (Hsp104) have the remarkable ability to rescue proteins from a previously aggregated state. Members of the ClpB/Hsp104 family form hexameric ring structures of ~600 kDa in molecular weight and convert chemical energy derived from ATP-binding and hydrolysis into mechanical work. The goal of this research is to provide a detailed mechanistic understanding how ClpB and Hsp104 facilitate the dissociation of previously aggregated proteins. Project 1: Structure of the ClpB hexamer ClpB is an ATP-dependent molecular machine, which forms a 600-kDa hexameric ring structure and belongs to the Clp/Hsp100 family of AAA+ proteins. Unlike other molecular chaperones, however, ClpB neither promotes the forward folding nor prevents the aggregation of proteins. Instead, ClpB has the remarkable ability to rescue stress-damaged proteins from an aggregated state; a function that is essential for induced thermotolerance. While the structure-function relationship is beginning to be understood, it remains unclear how ClpB converts the energy derived from ATP binding and hydrolysis into mechanical work. Project 2: Structure of the Hsp104 molecular chaperone First discovered as an essential component in the yeast stress response, Hsp104 is an ATP-dependent protein-remodeling factor, which, like ClpB, can rescue stress-damaged proteins from a previously aggregated state. While the ability to do so is shared with bacterial ClpB, the underlying mechanism is different. For instance, it has been proposed that the second AAA domain of Hsp104 is essential for oligomerization and is required for substrate binding while the reverse is true for ClpB. To provide a detailed mechanistic understanding of Hsp104, we are using cryoEM to determine the structure of Hsp104 both in the nucleotide-bound and -free states