Structure and function of ClpXP

ClpXP的结构和功能

• 批准号: 10373109
• 负责人: Robert T Sauer
• 金额: $ 38.78万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10373109
• 关键词: ATP Hydrolysis; ATP phosphohydrolase; ATP-Dependent Proteases; Address; Antibiotics; Basic Science; Biochemical; Biotechnology; C-terminal; Cell physiology; Cells; Coupled; Defect; Disease; Ensure; Enzymes; Escherichia coli; Family; Goals; Growth; Health Promotion; Infertility; Light; Mammals; Mechanics; Medicine; Mitochondria; Molecular; Mycobacterium tuberculosis; N-terminal; Pathogenesis; Peptide Hydrolases; Play; Positioning Attribute; Proteins; Role; Specificity; Structure; Time; Work; experimental study; hearing impairment; heme biosynthesis; polypeptide; prevent; protein degradation; protein folding

Project Summary AAA+ proteases remove toxic proteins and regulate many other important cellular processes that promote health and prevent disease. At the same time, protein degradation must be carefully regulated. AAA+ proteases assemble into multi-subunit structures with an internal proteolytic chamber, accessible through narrow channels that exclude natively folded proteins. This mechanism protects most proteins from unintended degradation and requires specific substrates to be recognized, unfolded, and then translocated into the degradation chamber. In the AAA+ ClpXP protease, for example, a ring hexamer of ClpX uses the energy of ATP hydrolysis to unfold specific target proteins and translocate them into ClpP for degradation. ClpXP is one of the best-characterized AAA+ proteases and is a paradigm for other ATP- dependent proteases and AAA+ remodeling machines. These ATP-fueled enzymes perform a wide variety of mechanical remodeling, transport, and regulatory tasks in the cell. In mammals, loss of mitochondrial ClpP results in infertility, hearing loss, and growth defects, whereas mitochondrial ClpX plays an important role in heme biosynthesis. Bacterial ClpXP can promote pathogenesis and is a validated antibiotic target in M. tuberculosis. Substantial progress has been made in understanding the general biochemical and structural features of E. coli ClpXP and other AAA+ enzymes but important and fundamental questions concerning the molecular mechanisms of these machines remain. For example, it is not known how ClpX identifies many classes of N-terminal and C-terminal degrons, whether ClpX rotates with respect to ClpP during normal function, whether proofreading helps ensure degradation specificity, how multiple substrate chains can be simultaneously translocated through the ClpX channel, what the detailed and interacts with polypeptide substrates during mechanical unfolding, whether ATP hydrolysis can occur at multiple positions in the spiral ClpX ring or only at one or a few special positions, and how the detailed ATPase cycle is coupled to mechanical work. The experiments described in this proposal will address these questions and provide a conceptual framework applicable to studies of the entire superfamily of AAA+ machines.

项目概要 AAA+ 蛋白酶去除有毒蛋白质并调节许多其他重要的细胞过程 促进健康和预防疾病。同时，蛋白质的降解必须 精心监管。 AAA+ 蛋白酶组装成具有内部结构的多亚基结构 蛋白水解室，可通过排除天然折叠蛋白质的狭窄通道进入。 这种机制可以保护大多数蛋白质免遭意外降解，并且需要特定的 底物被识别、展开，然后转移到降解室中。在 AAA+ ClpXP 蛋白酶，例如 ClpX 的环状六聚体使用 ATP 的能量 水解以展开特定靶蛋白并将其转移到 ClpP 中进行降解。 ClpXP 是最具特色的 AAA+ 蛋白酶之一，也是其他 ATP- 的范例 依赖性蛋白酶和 AAA+ 重塑机器。这些以 ATP 为燃料的酶执行 细胞中各种各样的机械重塑、运输和调节任务。在哺乳动物中， 线粒体 ClpP 缺失会导致不孕、听力损失和生长缺陷，而 线粒体 ClpX 在血红素生物合成中发挥着重要作用。细菌 ClpXP 可促进 发病机制，并且是结核分枝杆菌中经过验证的抗生素靶点。取得了实质性进展 了解大肠杆菌 ClpXP 的一般生化和结构特征 和其他 AAA+ 酶，但有关分子的重要和基本问题 这些机器的机制仍然存在。例如，尚不清楚 ClpX 如何识别许多 N 端和 C 端降解决定子的类别，ClpX 是否相对于 ClpP 旋转 在正常功能期间，校对是否有助于确保降解特异性，如何 多个底物链可以通过 ClpX 通道同时转位，什么 机械展开过程中的细节和与多肽底物的相互作用，无论是 ATP 水解可以发生在 ClpX 螺旋环的多个位置，也可以仅发生在一个或几个位置 特殊位置，以及详细的 ATP 酶循环如何与机械功耦合。这 本提案中描述的实验将解决这些问题并提供概念性的 适用于整个 AAA+ 机器超家族研究的框架。