NUCLEOTIDE DEPENDENT CONFORMATIONAL CHANGES IN S54-DEPENDENT AAA+ATPASES

S54 依赖的 AAA 腺苷酸酶中核苷酸依赖的构象变化

• 批准号: 7369131
• 负责人: B TRACY NIXON
• 金额: $ 0.44万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7369131
• 关键词: NUCLEOTIDE; DEPENDENT; CONFORMATIONAL; CHANGES; S54

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. Why do defects in molecular machines (AAA+ ATPases) cause disease? These protein machines convert ATP hydrolysis into mechanical work. It is clear that both human cells and disease causing pathogens use this work to physically manipulate proteins or DNA to dismantle and reassemble membranes or other organelles, to replicate DNA and traverse cell division, to repair damaged proteins, or to regulate gene expression. But, we do not know how these molecular machines convert ATP hydrolysis into mechanical work. A major impediment to defining these mechanisms has been our inability to probe detailed conformational changes that are related to controlling these ATPases as they step through ATP binding, hydrolysis and product release. Our project focused on defining structural changes that occur to regulate assembly of s54-dependent AAA+ ATPases, and that accompany the ATP hydrolysis cycle. These activators remodel the s54-form of bacterial RNA polymerase to enable it to initiate transcription in bacteria. Previous solution structures derived from small angle scattering data (published in 2005) revealed that in one case a regulatory domain adopts two homo-dimeric forms, alternately repressing or derepressing motor assembly by adjacent ATPase domains; in another case, regulatory and ATPase domains were found to cooperate to stabilize the assembled motor. Similar data collected in 2005 revealed a) conformational changes that are coupled with nucleotide status and that mediate two distinct interactions with the target protein, s54, and b) structure of one of those complexes. These latter results are being submitted for publication.

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。为什么分子机器（AAA+ ATP酶）的缺陷会导致疾病？这些蛋白质机器将ATP水解转化为机械功。很明显，人类细胞和致病病原体都利用这项工作来物理操纵蛋白质或DNA，以拆除和重组膜或其他细胞器，复制DNA并穿越细胞分裂，修复受损蛋白质或调节基因表达。但是，我们不知道这些分子机器如何将ATP水解转化为机械功。定义这些机制的一个主要障碍是我们无法探测与控制这些ATP酶有关的详细构象变化，因为它们通过ATP结合，水解和产物释放。我们的项目集中于定义发生调节s54依赖性AAA+ ATP酶的组装以及伴随ATP水解循环的结构变化。这些激活剂重塑细菌RNA聚合酶的s54形式，使其能够在细菌中启动转录。以前的解决方案结构来自小角散射数据（发表于2005年）显示，在一种情况下，一个调节结构域采用两种同源二聚体形式，交替抑制或解抑制电机组装相邻的ATP酶结构域;在另一种情况下，调节和ATP酶结构域被发现合作，以稳定组装的电机。2005年收集的类似数据揭示了a）与核苷酸状态偶联的构象变化，并介导与靶蛋白s54的两种不同相互作用，以及B）这些复合物之一的结构。这些最后的结果正在提交出版。